Prognostic value of a modified‑immune scoring system in patients with pathological T4 colorectal cancer

Tumor-infiltrating immune cells, such as lymphocytes and macrophages, have been associated with tumor aggressiveness, prognosis and treatment response in colorectal cancer (CRC). An immune scoring system, Immunoscore (IS), based on tumor-infiltrating T cells in stage I-III CRC, was used to predict prognosis. An alternative immune scoring signature of immune activation (SIA) reflects the balance between anti- and pro-tumoral immune components. The present study aimed to evaluate the prognostic value of modified IS (mIS) and modified SIA (mSIA) in locally advanced pathological T4 (pT4) CRC, including stage IV CRC. Immunohistochemical staining for immune cell markers, such as CD3 (pan-T cell marker), CD8 (anti-tumoral cytotoxic T cell marker) and CD163 (tumor-supportive macrophage marker), in specimens from patients with radically resected pT4 CRC at stages II-IV was performed. mIS levels in the T4 CRC cohort were not associated with prognosis. However, low mSIA levels were associated with low survival. Furthermore, low mSIA was an independent predictor of recurrence in patients with radically resected pT4 CRC. In patients with CRC who did not receive postoperative adjuvant chemotherapy, low mSIA was a major poor prognostic factor; however, this was not observed in patients receiving adjuvant chemotherapy. Evaluation of the tumor-infiltrating immune cell population could serve as a valuable marker of recurrence and poor prognosis in patients with locally advanced CRC. mSIA assessment after radical CRC resection may be promising for identifying high-risk patients with pT4 CRC who require aggressive adjuvant chemotherapy.

Small Bowel Obstruction Caused by Type IV Hiatal Hernia

Type IV hiatal hernia of the esophagus is characterized by herniation of the stomach and associated organs, such as the spleen, large and small bowel, and pancreas, through the esophageal hiatus. It is a relatively rare form of hiatal hernia that sometimes requires emergency surgery due to gastric incarceration, volvulus, and strangulation. Of these, small bowel obstruction is extremely rare and requires surgery. We report the case of an 83-year-old woman who was admitted to the hospital for small bowel obstruction caused by an ileum that had incarcerated the esophageal hiatus; emergency laparoscopic surgery was performed.

MAdCAM-1 targeting strategy can prevent colitic cancer carcinogenesis and progression via suppression of immune cell infiltration and inflammatory signals

Chronic inflammation caused by infiltrating immune cells can promote colitis-associated dysplasia/colitic cancer in ulcerative colitis (UC) by activating inflammatory cytokine signalling through the IL-6/p-STAT3 and TNFα/NF-κB pathways. Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) expressed on high endothelial venules promotes the migration of immune cells from the bloodstream to the gut via interaction with α4β7 integrin expressed on the immune cells. MAdCAM-1, has therefore drawn interest as a novel therapeutic target for treating active UC. However, the role of MAdCAM-1-positive endothelial cells in immune cell infiltration in dysplasia/colitic cancers remains unclear. We evaluated the expression of MAdCAM-1, CD31 and immune cell markers (CD8, CD68, CD163 and FOXP3) in samples surgically resected from 11 UC patients with dysplasia/colitic cancer and 17 patients with sporadic colorectal cancer (SCRC), using immunohistochemical staining. We used an azoxymethane/dextran sodium sulphate mouse model (AOM/DSS mouse) to evaluate whether dysplasia/colitic cancer could be suppressed with an anti-MAdCAM-1 blocking antibody by preventing immune cell infiltration. The number of MAdCAM-1-positive vessels and infiltrating CD8+ , CD68+ and CD163+ immune cells was significantly higher in dysplasia/colitic cancer than in normal, SCRC and UC mucosa. In AOM/DSS mice, the anti-MAdCAM-1 antibody reduced the number, mean diameter, depth of tumours, Ki67 positivity, number of CD8+ , CD68+ and CD163+ immune cells and the IL-6/p-STAT3 and TNF-α/NF-κB signalling. Our results indicate that targeting MAdCAM-1 is a promising strategy for controlling not only UC severity but also carcinogenesis and tumour progression by regulating inflammation/immune cell infiltration in patients with UC.

HLA Class I Expression Is Associated with DNA Damage and Immune Cell Infiltration into Dysplastic and Neoplastic Lesions in Ulcerative Colitis

Human leukocyte antigen class I (HLA-I) is considered a genetic pathogen for ulcerative colitis (UC). This study aimed to investigate the significance of DNA damage and HLA-I expression in infiltrating immune cells and immune checkpoint protein PD-L1 expression in dysplasia/colitic cancer (CC) and sporadic colorectal cancer (SCRC). We performed immunohistochemical staining for HLA-I, PD-L1, γH2AX (DNA damage marker), and immune cell markers such as CD8, FOXP3, CD68, and CD163 (in surgically resected specimens from 17 SCRC patients with 12 adjacent normal mucosa (NM) and 9 UC patients with 18 dysplasia/CC tumors. The ratio of membrane HLA-I-positive epithelial cells in UC and dysplasia/CC tissues was significantly higher than that in NM and SCRC. High HLA-I expression in dysplasia/CC was associated with high positivity of γH2AX and PD-L1 expression compared to SCRC. The infiltration of CD8-positive T cells and CD68-positive macrophages in HLA-I-high dysplasia/CC was significantly higher than in UC and SCRC. Dysplasia/CC specimens with DNA damage exhibited high levels of HLA-I-positive epithelial cells with high CD8- and CD68-positive immune cell infiltration compared to UC and SCRC specimens. Targeting DNA damage in UC may regulate immune cell infiltration, immune checkpoint proteins, and carcinogenesis by modulating DNA damage-induced HLA-I antigen presentation.

Surgical Techniques and Stoma-related Complications Associated With Emergency Stoma Creation

BACKGROUND/AIM

Determination of risk factors for stoma-related complications associated with emergency stoma creation may impact on reducing complications and improving the quality of life of ostomy patients; however, there are only few reports on stoma-related complications associated with emergency stoma creation. Our study aimed to identify risk factors associated with stoma-related complications after emergency surgery, and evaluate surgical techniques for good stoma creation in the emergency setting.

PATIENTS AND METHODS

A retrospective analysis of patient and surgical characteristics was performed in 104 consecutive patients who underwent ileostomy or colostomy as emergency surgery between January 2020 and December 2022 at the Gunma University Hospital.

RESULTS

Preoperative stoma site marking was performed in 70 (67.3%) patients. Colostomies and ileostomies were performed in 78 (75.0%) and 26 (25.0%) patients, respectively. The skin bridge technique was used in 13 (12.5%) patients. Stoma-related complications were diagnosed in 62 (59.6 %) patients, with peristomal skin disorders (47.1%) as the most common complication, followed by mucocutaneous separation (31.7%), and stoma retraction (19.2%). In the multivariate analysis, body mass index (BMI) [odds ratio (OR)=5.570, 95% confidence interval (CI)=1.233-25.167, p=0.026], skin bridge technique (OR=0.144, 95% CI=0.031-0.670, p=0.014), and stoma height (OR=0.134, 95% CI=0.038-0.469, p=0.002) were independent risk factors for stoma-related complications after emergency stoma creation.

CONCLUSION

In emergency stoma creation, higher BMI and lower stoma height are associated with stoma-related complications. Using the skin bridge technique could reduce the risk of stoma-related complications after emergency stoma creation.

Adjustment of creatinine clearance for carboplatin dosing in Calvert's formula and clinical efficacy for lung cancer

BACKGROUND

The Cockcroft-Gault formula is commonly used as a substitute for glomerular filtration rate (GFR) in Calvert's formula for carboplatin dosing, where adjusting serum creatinine measured using the enzymatic method with 0.2 mg/dL has been suggested in Japan. However, the effects of these adjustments on efficacy in patients with non-small-cell lung cancer remain unknown.

METHODS

We conducted a post hoc analysis of the PREDICT1 study (CJLSG1201), a multicenter prospective observational trial of carboplatin-pemetrexed. Glomerular filtration rate values in Calvert's formula were back-calculated from the administered dosages of carboplatin and the reported value of the target area under the curve. We estimated the serum creatinine adjustments and divided the patients into crude and adjusted groups.

RESULTS

Patients in the crude group (N = 169) demonstrated similar efficacy to those in the adjusted group (N = 104) in progression-free survival (PFS) and overall survival (OS) (hazard ratio [HR], 1.02; 95% confidence interval [CI], 0.76-1.35; p = 0.916 vs. HR, 0.87; 95% CI, 0.65-1.17; p = 0.363), with higher grade 3-4 hematologic toxicity. Among patients aged ≥75 years, the crude group (N = 47) showed superior efficacy compared with the adjusted group (N = 17) in PFS and OS (HR, 0.37; 95% CI, 0.20-0.69; p = 0.002 vs. HR, 0.43; 95% CI, 0.23-0.82; p = 0.010).

CONCLUSIONS

Serum creatinine adjustment may be associated with similar efficacy compared to the crude serum creatinine value. In older patients, the adjustment should be cautiously applied owing to the potential for reduced efficacy.

Two-team Total Mesorectal Excision and Lateral Pelvic Lymph Node Dissection Using Transanal Approach for Rectal Cancer: A Retrospective Study

BACKGROUND/AIM

Lateral lymph node dissection is a locally advanced rectal cancer treatment option. Despite its complexities, such as prolonged operative time and increased blood loss, a transanal approach with an abdominal approach may help mitigate these drawbacks.

PATIENTS AND METHODS

Between July 2013 and June 2022, 40 patients underwent radical laparoscopic surgery with lateral lymph node dissection for rectal cancer. Among them, 29 and 11 patients underwent total mesorectal excision and lateral lymph node dissection without transanal approach (conventional surgery) and with transanal approach (two-team surgery), respectively. The clinical findings, surgical outcomes, pathology results, and prognoses of conventional and two-team surgeries were retrospectively compared.

RESULTS

Compared to conventional surgery, two-team surgery involves increased organ and nerve resections, shorter operation time (286 vs. 548 min, p<0.001), and less blood loss (20 vs. 158 ml, p<0.001). Although postoperative complications were similar between groups, the two-team surgery group had a shorter hospital stay (p=0.006). Pathologically, all patients who underwent two-team surgery had a distal resection margin of at least 20 mm, and no recurrence was observed. With conventional surgery, 63.6% of patients had a 10-19 mm margin, and 36.4% had a margin of ≥20 mm, except for abdominoperineal resection.

CONCLUSION

Total mesorectal excision and lateral lymph node dissection with the transanal approach as a two-team surgery are safe and feasible. Two-team surgery resulted in better outcomes than conventional surgery regarding operative time, blood loss, shorter postoperative hospital stay, and adequate distal resection margin.

Sigmoid colon schwannoma difficult to distinguish from peritoneal dissemination 13 years after pancreatic neuroendocrine tumor surgery

BACKGROUND

Schwannoma, which clinicians sometimes struggle to diagnose, is a tumor arising from Schwann cells of peripheral nerves, often in the soft tissues and rarely in the gastrointestinal tract. Pancreatic neuroendocrine tumor (PNET) is rare among pancreatic tumors, and recurrence can occur long after resection. Here, we were presented with a case where a sigmoid colon schwannoma was difficult to distinguish from a postoperative recurrence of PNET and was diagnosed after laparoscopic resection.

CASE PRESENTATION

A 51-year-old man was diagnosed with PNET (NET G2) after a distal pancreatectomy (DP) 13 years ago. The patient underwent hepatectomy due to liver metastasis 12 years after initial radical surgery. The follow-up magnetic resonance imaging (MRI) after hepatectomy showed pelvic nodules, and laparoscopic surgery was performed for both diagnosis and treatment because peritoneal dissemination of PNET could not be ruled out. Since the tumor was in the sigmoid colon, a partial colon resection was performed. The histopathological diagnosis was a schwannoma, and the patient was discharged on the seventh postoperative day.

CONCLUSIONS

We experienced a case of sigmoid colon schwannoma that was difficult to differentiate from peritoneal dissemination of PNET and was later diagnosed after laparoscopic resection. In addition, this case involved a long-term postoperative recurrence of PNET that was amenable to radical resection, further establishing the importance of long-term imaging follow-up.

Leukocyte Depletion and Size-Based Enrichment of Circulating Tumor Cells Using a Pressure-Sensing Microfiltration Device

Considering the challenges in isolating circulating tumor cells (CTCs) pertaining to cellular stress and purity, we report the application of a blood microfiltration device as an optimal approach for noninvasive liquid biopsy to target CTCs. We experimentally analyzed the filtration behavior of the microfilter using pressure sensing to separate tumor cells from leukocytes in whole blood. This approach achieved an average recovery of >96% of the spiked tumor cells and depletion of >99% of total leukocytes. Furthermore, we carried out genomic profiling of the CTCs using the blood microfiltration device. The method was also applied in a clinical setting; DNA amplification was performed using a small number of microfiltered CTCs and epidermal growth factor receptor mutations were successfully detected to characterize the efficacy of molecularly targeted drugs against lung cancer. Overall, the proposed method can provide a tool for evaluating efficient filtration pressure to concentrate CTCs from whole blood.

Enterolith Causing Afferent Loop Perforation After Distal Gastrectomy

Afferent loop syndrome is a complication that occurs after the Billroth Ⅱ reconstruction or Roux-en-Y reconstruction and can also be caused by enteroliths. We experienced a case of duodenal perforation due to afferent loop syndrome caused by an enterolith, in which surgical removal of the enterolith and decompression of the duodenum were effective. A 73-year-old female who underwent distal gastrectomy and Roux-en-Y reconstruction for gastric cancer 14 years ago came to the hospital with acute abdominal pain and underwent emergency surgery for afferent loop syndrome and duodenal perforation due to enterolith. The patient underwent removal of the enterolith, drain placement, and placement of a decompression tube in the duodenum. Postoperatively, percutaneous drainage of the intra-abdominal abscess was necessary, but the patient was saved without reoperation. Afferent loop perforation may occur with obstruction due to enteroliths, and the surgical insertion of a tube to decompress the afferent loop is effective.

Francium ion source with novel methods of target heating and beam characterization

We have developed a novel ion source and beam diagnostic system for the production and detection of radioactive francium (Fr) isotopes. The Fr ions are produced using a fusion-evaporation reaction at the RIKEN Nishina Center, Japan. The installation of an infrared heater has enabled a precise and rapid control of the target temperature, and the newly developed diagnostic system allows for a quantitative characterization of the extracted ion beam. With the new system, an analysis of the Fr208-211 isotopes has been performed. Additionally, the flux of Fr210 ions has been estimated as 6.7 × 10⁶ s^-1 corresponding to an extraction efficiency of 24.5% and a beam purity of 1.6 × 10^-5.

Relationship Between C-reactive Protein-to-albumin Ratio Before and After Bowel Decompression and Prognosis in Acute Malignant Large Bowel Obstruction

BACKGROUND/AIM

We investigated the relationship between prognosis and the necessity of decompression of large bowel obstruction (LBO) among patients with colorectal cancer admitted to the hospital in an emergency, as well as the correlation between prognosis and improvement in the C-reactive protein-to-albumin ratio (CAR) after decompression.

PATIENTS AND METHODS

Seventy-four patients admitted to the hospital between 2013 and 2021 in an emergency due to LBO were included. We examined perioperative clinicopathological factors, bowel decompression type, and prognosis.

RESULTS

Of the 74 patients, 24 (32.4%) required bowel decompression. A higher percentage of patients who required bowel decompression had a colorectal obstruction scoring system (CROSS) score 0 (p<0.001) with higher frequency of nutritional disorders (p=0.063) than that in no bowel decompression-requiring patients. The 3-year-disease-free survival was 70.8% in the no decompression-requiring group and 26.9% in the bowel decompression group (p=0.007), while the 3-year-overall survival was 90.8% and 76.5%, respectively (p=0.001). The 3-year-disease-free survival was 49.2% in the improved CAR group and 0.0% in the non-improved CAR group (p=0.024), while the 3-year-overall survival was 91.7% and 56.3%, respectively (p=0.061).

CONCLUSION

The necessity of emergency decompression was associated with a poorer prognosis, compared to the no decompression-requiring group. Similarly, a CROSS score of 0 was an independent poor prognostic factor. Among patients who required emergency bowel decompression, those who showed improvement in CAR before and after decompression treatment had a better prognosis than those who did not.

Significance of routine preoperative prone computed tomography for predicting intractable cases of inguinal hernias treated by transabdominal preperitoneal repair

Physical examination is the standard diagnostic approach for adult inguinal hernias. We aimed to evaluate the clinical utility of routine preoperative computed tomography scans in the prone position for predicting intractable cases of inguinal hernias before performing transabdominal preperitoneal repairs. We retrospectively analyzed 56 lesions in 48 patients with inguinal hernias who underwent prone computed tomography scans prior to transabdominal preperitoneal repairs. To assess the ability of prone computed tomography to enable the accurate preoperative diagnosis of inguinal hernias, we compared preoperative hernia types as classified through hernia computed tomography and intraoperative diagnosis. We also analyzed the relationship between operation time and hernia type in unilateral cases (n = 40). The overall hernia computed tomography detection and classification accuracy rates were 81.0% and 83.9%, respectively, using the Japan Hernia Society classification system (2009 version) and 84.3% and 91.2%, respectively, using the European Hernia Society classification system. There were no differences in the hernia type frequencies between the shorter (n = 20) and longer (n = 20) operation time groups. Two patients had sliding inguinal hernias with prolapsing bladders, both of which were detectable using preoperative prone computed tomography. Although transabdominal preperitoneal repairs were completed in both cases, the operation times were exceptionally long (185 and 291 minute). Preoperative prone computed tomography is useful for predicting intractable cases of inguinal hernias. Prone computed tomography can play a significant role in not only typing and differentiating hernias from other diseases, but also in helping surgeons appropriately treat unexpected intractable cases with laparoscopic surgery.

Differences in prognosis and underuse of adjuvant chemotherapy between elderly and non-elderly patients in stage III colorectal cancer

Aim

We aimed to clarify the use of adjuvant chemotherapy and the prognosis of elderly colorectal cancer patients compared with non-elderly patients, and the usefulness of sarcopenia as an indicator for the introduction and completion of adjuvant chemotherapy.

Methods

Between 2013 and 2021, 215 patients with pStage III disease were included. We investigated perioperative clinicopathological factors, adjuvant chemotherapy details, and prognosis. Preoperative sarcopenia status was evaluated using computed tomography images. Elderly patients were defined as those aged ≥70 years.

Results

We included 121 (56.3%) and 94 (43.7%) non-elderly and elderly patients, respectively. Among the elderly patients, 47 had sarcopenia. There were no significant differences in the incompletion rate of adjuvant chemotherapy between elderly and non-elderly patients (27.1%/16.2%, P = 0.119). The most common reason for the discontinuation of adjuvant chemotherapy was side effects, regardless of age. The respective 3-year-disease free survival of patients with no/completed/incomplete adjuvant chemotherapy were 65.5%, 80.2%, and 57.7% for non-elderly patients (P = 0.045) and 73.4%, 70.6%, and 71.6% for elderly patients (P = 0.924). The number of elderly patients with sarcopenia was significantly higher in patients without adjuvant chemotherapy (P = 0.004) and those with incomplete adjuvant chemotherapy (P = 0.004). The 3-year-disease free survival of elderly sarcopenic patients without and with adjuvant chemotherapy were 78.3% and 59.2%, respectively (P = 0.833).

Conclusion

Elderly patients did not show a benefit of adjuvant chemotherapy regardless of whether they had completed adjuvant chemotherapy, unlike non-elderly patients. Moreover, the evaluation of preoperative sarcopenia in elderly colorectal cancer patients may be useful in determining the indication for adjuvant chemotherapy.

P–763 Neonatal outcomes of the first 65 infants delivered after IVF treatment with progestin-primed ovarian stimulation using dienogest in patients with endometriosis

Study question

What is the perinatal outcome of pregnancies resulting from a controlled ovarian hyperstimulation (COH) regimen of progestin-primed ovarian stimulation (PPOS) protocol using dienogest (DNG) in patients with endometriosis?

Summary answer

No difference in mean birth weight, however preterm and low birth weight babies are significantly more in the group treated with PPOS using DNG.

What is known already

Dienogest is an oral progestin effective for the treatment of endometriosis, such as reduction of endometrial lesion and control of pain intensity with safety profile and good tolerability. We reported for the first time in the world that DNG was better than dydrogesterone (DYG) for PPOS in terms of the mature oocytes rate and the fertilization rate in patients with endometriosis. Although there have been several reports of infants born with PPOS using DYG, it is essential to report on the perinatal outcome of embryos transferred after treatment with PPOS using DNG from now on. Study design, size, duration: We prospectively investigated the perinatal outcomes of 65 newborns which were the result of using a new COH regimen; PPOS with DNG. The results were compared with perinatal outcome data of babies born between 2018 and 2020 to 815 patients who underwent assisted reproductive technology (ART) treatment at our fertility center. As for the congenital malformation rate, the data was also compared with the 2017 Japanese data bank of babies born after ART treatment.

Participants/materials, setting, methods

We studied the perinatal data of all babies born after transfer of frozen embryos acquired by COH using PPOS protocol with DNG. The rate of maternal complications during pregnancy, pregnancy duration, birth weight, congenital malformations and method of delivery were investigated. We compared the perinatal outcomes of infants born after in vitro fertilization (IVF) and frozen embryo transfer at our center during the same period.

Main results and the role of chance

Perinatal data of 65 babies (study group) were compared with the perinatal data of 840 babies born after IVF at our center, and 47807 babies born after ART in Japan, 2017. We found 3 twin and 59 singleton pregnancies in the study group, compared to 23 twins, 1 triplet and 791 singleton pregnancies during the same period at our center. Considering singletons, there was no difference in mean birthweight (study group; 2893.2±652g vs. total at our center; 3001.2±425g, respectively, p = 0.102). Preterm births (&lt;37 weeks) were significantly more frequent in the PPOS using DNG treatment group than in total at our center (19.2% vs. 9.7%, p = 0.016). The percentage of infants with a birth weight &lt; 2.5 kg was also significantly higher in the PPOS treatment group compared to the total at our center (22.6% vs.11.9%, p = 0.015). The Caesarean section rate was 53.2% in the study group vs. 47.1% control group of our center respectively (p = 0.353). One babies in the study group had malformations in the ocular region. There was no significant difference in congenital malformations between the study group and ART data bank in Japan, 2017 (OR 0.67, 95% CI 0.093: 4.836).

Limitations, reasons for caution

The number of babies is still low, further prospective studies including larger populations are needed to confirm the efficacy of PPOS protocol with DNG.

Wider implications of the findings: This is the first report on the perinatal outcome of babies born by a new COH method using PPOS with DNG, which is a combination of endometriosis treatment and COH for IVF. The association of endometriosis with preterm birth and low birth weight needs to be further investigated.

Trial registration number

UMIN000031111

Comparison of the Hepatic Effects of Phenobarbital in Chimeric Mice Containing Either Rat or Human Hepatocytes With Humanized Constitutive Androstane Receptor and Pregnane X Receptor Mice

Using a chimeric mouse humanized liver model, we provided evidence that human hepatocytes are refractory to the mitogenic effects of rodent constitutive androstane receptor (CAR) activators. To evaluate the functional reliability of this model, the present study examined mitogenic responses to phenobarbital (PB) in chimeric mice transplanted with rat hepatocytes, because rats are responsive to CAR activators. Treatment with 1000 ppm PB for 7 days significantly increased replicative DNA synthesis (RDS) in rat hepatocytes of the chimeric mice, demonstrating that the transplanted hepatocyte model is functionally reliable for cell proliferation analysis. Treatment of humanized CAR and pregnane X receptor (PXR) mice (hCAR/hPXR mice) with 1000 ppm PB for 7 days significantly increased hepatocyte RDS together with increases in several mitogenic genes. Global gene expression analysis was performed with liver samples from this and from previous studies focusing on PB-induced Wnt/β-catenin signaling and showed that altered genes in hCAR/hPXR mice clustered most closely with liver tumor samples from a diethylnitrosamine/PB initiation/promotion study than with wild-type mice. However, different gene clusters were observed for chimeric mice with human hepatocytes for Wnt/β-catenin signaling when compared with those of hCAR/hPXR mice, wild-type mice, and liver tumor samples. The results of this study demonstrate clear differences in the effects of PB on hepatocyte RDS and global gene expression between human hepatocytes of chimeric mice and hCAR/hPXR mice, suggesting that the chimeric mouse model is relevant to humans for studies on the hepatic effects of rodent CAR activators whereas the hCAR/hPXR mouse is not.

PD-L1 upregulation is associated with activation of the DNA double-strand break repair pathway in patients with colitic cancer

Ulcerative colitis (UC) is a DNA damage-associated chronic inflammatory disease; the DNA double-strand break (DSB) repair pathway participates in UC-associated dysplasia/colitic cancer carcinogenesis. The DSB/interferon regulatory factor-1 (IRF-1) pathway can induce PD-L1 expression transcriptionally. However, the association of PD-L1/DSB/IRF-1 with sporadic colorectal cancer (SCRC), and UC-associated dysplasia/colitic cancer, remains elusive. Therefore, we investigated the significance of the PD-L1/DSB repair pathway using samples from 17 SCRC and 12 UC patients with rare UC-associated dysplasia/colitic cancer cases by immunohistochemical analysis. We compared PD-L1 expression between patients with SCRC and UC-associated dysplasia/colitic cancer and determined the association between PD-L1 and the CD8+ T-cell/DSB/IRF-1 axis in UC-associated dysplasia/colitic cancer. PD-L1 expression in UC and UC-associated dysplasia/colitic cancer was higher than in normal mucosa or SCRC, and in CD8-positive T lymphocytes in UC-associated dysplasia/colitic cancer than in SCRC. Moreover, PD-L1 upregulation was associated with γH2AX (DSB marker) and IRF-1 upregulation in UC-associated dysplasia/colitic cancer. IRF-1 upregulation was associated with γH2AX upregulation in UC-associated dysplasia/colitic cancer but not in SCRC. Multicolour immunofluorescence staining validated γH2AX/IRF-1/PD-L1 co-expression in colitic cancer tissue sections. Thus, immune cell-induced inflammation might activate the DSB/IRF-1 axis, potentially serving as the primary regulatory mechanism of PD-L1 expression in UC-associated carcinogenesis.

Low level of stromal lectin-like oxidized LDL receptor 1 and CD8+ cytotoxic T-lymphocytes indicate poor prognosis of colorectal cancer

Background

Lectin‐like oxidized LDL receptor‐1 (LOX‐1) has been identified as a new marker for functional myeloid‐derived suppressor cells (MDSCs) that exhibit an immunosuppressive phenotype in the tumor microenvironment (TME). However, the role of LOX‐1⁺ cells in the TME of colorectal cancer (CRC) remains unknown.

Aim

This study aimed to determine the expression and significance of LOX‐1 in the TME of clinical CRC specimens.

Methods and results

We performed immunohistochemical and genetic analyses of LOX‐1, CD8, KRAS, and BRAF in 128 resected CRC specimens and determined the expression of IFN‐γ and IL‐10 using real‐time reverse transcription‐polymerase chain reaction. We analyzed the correlation between LOX‐1, TME factors, gene alteration, clinicopathological factors, and disease prognosis. The co‐expression pattern of LOX‐1, hematopoietic markers, and a fibroblast marker was evaluated using multiplex immunofluorescence staining. Low stromal LOX‐1 expression and low intratumoral CD8⁺ cytotoxic T‐lymphocyte (CTL) status correlated with poor prognosis. Moreover, stromal LOX‐1‐low/CD8⁺ CTL‐low status was the most important independent prognostic factor of poor overall survival. Most of the LOX‐1⁺ stromal cells were positive for CD163⁺, indicating they were CD163⁺ M2 macrophages.

Conclusions

The MDSC marker, LOX‐1, was mainly expressed by M2 macrophages in CRC tissues. LOX‐1⁺ macrophages and CD8⁺ CTLs may serve as useful biomarkers for predicting the prognosis of CRC.

Bowel obstruction due to Chlamydia trachomatis: a case report and review of literature

Background

Chlamydial infection is a difficult-to-diagnose type of sexually transmitted disease that occurs mainly in young people. We report a case of bowel obstruction caused by intrapelvic adhesions formed by chlamydial infection.

Case presentation

This patient was a 23-year-old woman who had been suffering from acute abdominal pain. She had been previously treated several times for intrapelvic abscesses and had a history of chlamydial infection. Endometriosis was thought to be the cause of her pelvic abscess based on endoscopic findings. Computed tomography demonstrated a small bowel obstruction caused by a pelvic abscess. However, the diagnosis could not be confirmed. She underwent laparoscopic surgery and was diagnosed with bowel obstruction due to adhesion of chlamydial infection based on the intraoperative findings and Chlamydia trachomatis antibody test. She was discharged 5 days after surgery.

Conclusions

It is necessary to consider the possibility of chlamydial infection as a cause for lower abdominal pain and unexplained bowel obstruction in female patients.

Outcomes of surgical treatment in patients with anorectal fistula cancer

Background

No standard treatment for anorectal fistula cancer, such as multidisciplinary therapy, has been established due to the rarity of the disease. Herein, we investigated patients with cancer associated with anorectal fistula who underwent surgery to clarify the clinicopathological characteristics and to propose future perspectives for treatment strategies.

Case presentation

Seven patients with cancer associated with anorectal fistula who underwent rectal amputation in our institute were analyzed with regard to clinical characteristics, pathological findings, surgical results, and prognosis. Four cases had Crohn's disease as an underlying cause. All seven cases were diagnosed as advanced stage. Preoperative [¹⁸F]-fluoro-2-deoxy-d-glucose (FDG)-positron emission tomography/computed tomography (FDG-PET/CT) showed abnormal FDG accumulation in six cases including four mucinous adenocarcinomas. Three cases that received preoperative hyperthermo-chemoradiotherapy achieved pathological R0 resection. Postoperative recurrence was observed in four cases including three with Crohn's disease and one resulting in death.

Conclusions

Anorectal fistula cancer is rare and difficult to be diagnosed at early stages. Mucinous adenocarcinoma associated with anorectal fistula tends to exhibit abnormal FDG accumulation by FDG-PET/CT unlike common colorectal mucinous adenocarcinoma. Preoperative hyperthermo-chemoradiotherapy may be effective in obtaining pathological complete resection.

A case of colorectal large cell neuroendocrine carcinoma accompanied by disseminated peritoneal leiomyomatosis

Background

Neuroendocrine carcinomas (NECs) of the colon are among the rarest types of colorectal cancers. Among these, large cell type neuroendocrine carcinoma (LCNEC) is particularly rare. Colorectal NEC is an aggressive disease, and there are few reports of long-term survivors. Here, we report a case of LCNEC accompanied by disseminated peritoneal leiomyomatosis that was difficult to diagnose.

Case presentation

The case involves a 62-year-old female found to be positive for fecal occult blood by medical examination. An endoscopy revealed a tumor in the ascending colon, and the biopsy revealed poorly differentiated cancer. Abnormal FDG accumulation with peritoneal thickening was visible on 18F-fluorodeoxyglucose positron-emission tomography (FDG-PET) and suspected to be peritoneal dissemination. Laparoscopic ileocecal resection was performed for the tumor of the ascending colon with abdominal wall invasion. At that time, numerous intra-abdominal nodules were observed, indicating peritoneal dissemination. The pathological diagnosis of the primary lesion was LCNEC, and the patient requested to undergo total peritoneal resection. After one course of chemotherapy with irinotecan plus cisplatin, she underwent total peritoneal resection, uterine annex resection, left inguinal lymph node resection, and intra-abdominal hyperthermic intraperitoneal chemotherapy with mitomycin C. Because a postoperative pathological examination revealed that the intra-abdominal nodules were leiomyomas, we diagnosed the patient with disseminated peritoneal leiomyomatosis. The left inguinal lymph node was diagnosed with a metastatic tumor. In summary, the final diagnosis was LCNEC in the ascending colon with inguinal lymph node metastasis. Postoperative chemotherapy has been administered to date. She is currently 18 months post-primary surgery and 15 months post-peritonectomy without apparent recurrence or metastatic findings.

Conclusion

We experienced a case of Stage IVa colorectal LCNEC accompanied by disseminated peritoneal leiomyomatosis. Although the prognosis is generally poor, multidisciplinary treatment for advanced colorectal LCNEC may result in a favorable outcome for some patients. If peritoneal dissemination is suspected during operation, sampling of the nodule to confirm the pathological diagnosis is advisable.

Development of an immuno-wall device for the rapid and sensitive detection of EGFR mutations in tumor tissues resected from lung cancer patients

Detecting molecular targets in specimens from patients with lung cancer is essential for targeted therapy. Recently, we developed a highly sensitive, rapid-detection device (an immuno-wall device) that utilizes photoreactive polyvinyl alcohol immobilized with antibodies against a target protein via a streptavidin–biotin interaction. To evaluate its performance, we assayed epidermal growth factor receptor (EGFR) mutations, such as E746_A750 deletion in exon 19 or L858R substitution in exon 21, both of which are common in non-small cell lung cancer and important predictors of the treatment efficacy of EGFR tyrosine kinase inhibitors. The results showed that in 20-min assays, the devices detected as few as 1% (E746_A750 deletion) and 0.1% (L858R substitution) of mutant cells. Subsequent evaluation of detection of the mutations in surgically resected lung cancer specimens from patients with or without EGFR mutations and previously diagnosed using commercially available, clinically approved genotyping assays revealed diagnostic sensitivities of the immuno-wall device for E746_A750 deletion and L858R substitution of 85.7% and 87.5%, respectively, with specificities of 100% for both mutations. These results suggest that the immuno-wall device represents a good candidate next-generation diagnostic tool, especially for screening of EGFR mutations.

Comparing incidences of infusion site reactions between brand-name and generic vinorelbine in patients with non-small cell lung cancer

AIM

This study aimed to compare the incidence of infusion site reactions (ISRs) induced by intravenous administration of brand-name and generic vinorelbine (VNR) for treating non-small cell lung cancer.

METHOD

This single-centre retrospective cohort study was conducted by medical chart review of VNR infusions. ISRs were defined as symptoms around the infusion site, including pain, redness and swelling. ISRs requiring treatment were defined as ISRs requiring treatments including steroid ointments, vein repuncture and local steroid injections.

RESULTS

In all, 1973 VNR infusions were administered to 340 patients (brand-name 141 patients, generic 199 patients). ISRs and ISRs requiring treatment were observed in 161 and 100 patients, respectively. The ISR incidence per patient and per injection was significantly higher in generic VNR-treated patients than in brand-name VNR-treated patients (53.3% vs 39.0%, P = 0.0112 and 15.0% vs 9.9%, P = 0.0008, respectively). The frequency of ISRs requiring treatment was also significantly higher in the generic group (per patient 36.7% vs 19.2%, P = 0.0005; per injection 11.3% vs 5.5%, P < 0.0001). Multivariate analysis revealed that generic VNR was significantly associated with an increased risk of ISRs (per patient adjusted odds ratio [AOR] 1.775, P = 0.0155; per injection AOR 1.672, P = 0.004) and ISRs requiring treatment (per patient AOR 2.422, P = 0.0012; per injection AOR 2.286, P = 0.001).

CONCLUSION

Intravenous infusion of generic VNR was associated with an increased risk of ISRs. Further research is needed to elucidate the mechanism underlying the increased incidence of ISRs with generic VNR.

Prognostic significance of β2-adrenergic receptor expression in patients with surgically resected colorectal cancer

PURPOSE

The β2-adrenergic receptor (β2AR) is highly expressed in various human cancers. The prognostic significance of its expression in patients with colorectal cancer (CRC) remains unclear. The aim of this study was to assess the prognostic role of β2AR expression in patients with surgically resected CRC.

METHODS

One hundred and forty-seven patients with surgically resected CRC were examined using immunohistochemistry. The expression of β2AR was assessed in the specimens of resected primary tumors.

RESULTS

β2AR was expressed in 52.3% of the patients' tumors. β2AR expression was significantly associated with T factor, N factor, and tumor cell proliferation (Ki-67 labeling index). Univariate analysis demonstrated that T factor, N factor, tumor stage, lymphatic permeation, vascular invasion, perineural invasion, β2AR expression, and Ki-67 labeling index were significant prognostic factors for worse disease-free survival (DFS); all but T factor were also significant predictors for worse overall survival (OS). Multivariate analysis confirmed that expression of β2AR was a significant prognostic marker for predicting worse DFS and OS.

CONCLUSION

β2AR expression was identified as a significant independent prognostic factor in patients with surgically resected CRC.

A 65-nm CMOS Fully Integrated Analysis Platform Using an On-Chip Vector Network Analyzer and a Transmission-Line-Based Detection Window for Analyzing Circulating Tumor Cell and Exosome

A fully integrated CMOS circuit based on a vector network analyzer and a transmission-line-based detection window for circulating tumor cell (CTC) and exosome analysis is presented for the first time. We have introduced a fully integrated architecture, which eliminates the undesired parasitic components and enables high-sensitivity, to analyze extremely low-concentration CTC in blood. The detection window was designed on the high-sensitive coplanar waveguide line. To validate the operation of the proposed system, a test chip was fabricated using 65-nm CMOS technology. Measurements were performed after adding a tiny lump of silicone or a droplet of water on its detection window. The measured results show |S_21| degradation of -1.96 dB and -6.04 dB for the silicone and the droplet, respectively, at 1.4 GHz. In addition, in another measurement using magnetic beads, it is confirmed that the proposed circuit can analyze even low concentrations of 20 beads/μL. As well as microbeads, measurement with CTCs was successfully demonstrated.

Spinal Cord Ischemia Secondary to Epidural Metastasis from Small Cell Lung Carcinoma

Patient: Male, 56

Final Diagnosis: Small cell lung carcinoma

Symptoms: Back pain • paralysis

Medication: —

Clinical Procedure: MRI

Specialty: Pulmonology

Artificial human Met agonists based on macrocycle scaffolds

Hepatocyte growth factor (HGF) receptor, also known as Met, is a member of the receptor tyrosine kinase family. The Met-HGF interaction regulates various signalling pathways involving downstream kinases, such as Akt and Erk. Met activation is implicated in wound healing of tissues via multiple biological responses triggered by the above-mentioned signalling cascade. Here we report the development of artificial Met-activating dimeric macrocycles. We identify Met-binding monomeric macrocyclic peptides by means of the RaPID (random non-standard peptide integrated discovery) system, and dimerize the respective monomers through rational design. These dimeric macrocycles specifically and strongly activate Met signalling pathways through receptor dimerization and induce various HGF-like cellular responses, such as branching morphogenesis, in human cells. This work suggests our approach for generating dimeric macrocycles as non-protein ligands for cell surface receptors can be useful for developing potential therapeutics with a broad range of potential applications.

Does surgery improve live birth rates in patients with recurrent miscarriage caused by uterine anomalies?

We found that congenital uterine anomalies have a negative impact on reproductive outcome in recurrent-miscarriage couples, being associated with further miscarriage with a normal embryonic karyotype. There has been no study comparing live birth rates between patients with and without surgery. We conducted a prospective study to prove that surgery for a bicornuate or septate uterus might improve the live birth rate. A total of 170 patients with congenital uterine anomalies suffering two or more miscarriages were examined. The live birth rate after ascertainment of anomalies, cumulative live birth rate and infertility rate, were compared between patients with and without surgery. In patients with a septate uterus, the live birth rate (81.3%) at the first pregnancy after ascertainment of anomalies with surgery tended to be higher than that (61.5%) in those without surgery. The infertility rates were similar in both groups, while the cumulative live birth rate (76.1%) tended to be higher than without surgery (60.0%). Surgery showed no benefit in patients with a bicornuate uterus for having a baby, but tended to decrease the preterm birth rate and the low birth weight. The possibility that surgery has benefits for having a baby in patients with a septate uterus suffering recurrent miscarriage could not be excluded.

Extraperitoneal colostomy in laparoscopic abdominoperineal resection using a hand inserted from the perineal side

INTRODUCTION

Extraperitoneal colostomy is considered to be more effective at preventing post-colostomy complications than intraperitoneal colostomy. However, this operation is difficult via laparoscopic surgery alone. We present an extraperitoneal colostomy technique using a hand inserted from the perineal side.

MATERIALS AND SURGICAL TECHNIQUE

Extraperitoneal colostomy was performed in five patients. After the rectum was resected, a hand was inserted into the abdominal cavity from the perineal side, and pneumoperitoneum was created. The peritoneum was dissected to make the extraperitoneal route, and the proximal colon was passed along this route with fingers and laparoscopic manipulation. All procedures were completed without tissue damage or hemorrhage. No patient developed a hernia or ileus postoperatively.

DISCUSSION

Laparoscopic abdominoperineal resection for an extraperitoneal colostomy is difficult via laparoscopic ports only. It can be simplified by operating with manual assistance via the perineal wound.

Intraoperative MRI for Brain Tumor Resection

Computer aided neurosurgery is now a highly advanced and essential technique, especially for the gliomas in the vicinity to the eloquent areas or deep inside of the brain. The intraoperative MRI (iMRI) is an important tool for the computer navigation system, considering brain shift under craniotomy. Real time navigation by the iMRI with brain mapping by subcortical stimulation and verbal confirmation by awake craniotomy can lead to the safe and precise tumor resection. The usefulness of an intraoperative low-field open MRI is defined for neuronavigation, especially for demonstration of the pyramidal tract in relation to the precise tumor location, considering brain shift during the operative procedure, to avoid tract injury.

[Minimally invasive cardiac surgery for transposition of the great arteries in neonates]

We evaluated our results of arterial switch operation (Jatene) for complete transposition of the great arteries between May 2003 and October 2005 particularly concerning various operation-related durations. Twenty neonates were studied. The mean age and body weight were 11.6 +/- 2.7 (range 5 to approximately 15) days and 3.0 +/- 0.4 kg, respectively. Duration of anesthesia, operation, extracorporeal circulation (ECC), and aortic cross-clamp were 199.4 +/- 30.1, 162.7 +/- 29.9, 91.6 +/- 8.8 and 59.8 +/- 8.1 minutes, respectively. Time differences between anesthesia and operation, operation and ECC, ECC and aortic cross-clamp were calculated, and their correlations with the duration of anesthesia were investigated. The items, whose coefficient of correlation with anesthetic time was greater than 0.6 were operation time, ECC time, aortic cross-clamp time, operation time minus ECC time, and operation time after ECC come-off. Furthermore, the operation time after ECC come-off was strongly correlated with plasma lactate concentrations and intraoperative bleeding. In conclusion, the time required for hemostasis and closure of the chest should be as short as possible. Therefore secure anastomoses with least hemorrhage possible is important.

An analog of a dipeptide-like structure of FK506 increases glial cell line-derived neurotrophic factor expression through cAMP response element-binding protein activated by heat shock protein 90/Akt signaling pathway

Glial cell line-derived neurotrophic factor (GDNF) is an important neurotrophic factor that has therapeutic implications for neurodegenerative disorders. We previously showed that leucine-isoleucine (Leu-Ile), an analog of a dipeptide-like structure of FK506 (tacrolimus), induces GDNF expression both in vivo and in vitro. In this investigation, we sought to clarify the cellular mechanisms underlying the GDNF-inducing effect of this dipeptide. Leu-Ile transport was investigated using fluorescein isothiocyanate-Leu-Ile in cultured neurons, and the results showed the transmembrane mobility of this dipeptide. By liquid chromatography-mass spectrometry and quartz crystal microbalance assay, we identified heat shock cognate protein 70 as a protein binding specifically to Leu-Ile, and molecular modeling showed that the ATPase domain is the predicted binding site. Leu-Ile stimulated Akt phosphorylation, which was attenuated significantly by heat shock protein 90 (Hsp90) inhibitor geldanamycin (GA). Moreover, enhanced interaction between phosphorylated Akt and Hsp90 was detected by immunoprecipitation. Leu-Ile elicited an increase in cAMP response element binding protein (CREB) phosphorylation, which was inhibited by GA, indicating that CREB is a downstream target of Hsp90/Akt signaling. Leu-Ile elevated the levels of GDNF mRNA and protein expression, whereas inhibition of CREB blocked such effects. Leu-Ile promoted the binding activity of phosphorylated CREB with cAMP response element. These findings show that CREB plays a key role in transcriptional regulation of GDNF expression induced by Leu-Ile. In conclusion, Leu-Ile activates Hsp90/Akt/CREB signaling, which contributes to the upregulation of GDNF expression. It may represent a novel lead compound for the treatment of dopaminergic neurons or motoneuron diseases.

Tentorial schwannoma: a case report

A rare case of tentorial schwannoma in a 29-year-old male is described. The schwannoma was located within the leaves of the tentorium. MRI showed a wedge-shaped enhancing tumour. Exact nerve of origin of the tumour could not be identified. We speculate that the tumour arose from the tentorial branch of the trigeminal nerve. The literature concerning intracranial schwannoma unrelated to a major cranial nerve is reviewed.

A phylogenetic-tree analysis elucidating nosocomial transmission of hepatitis C virus in a haemodialysis unit

Nosocomial transmission of hepatitis C virus (HCV) subtype 1b involving 11 haemodialysis patients occurred in a haemodialysis unit in Japan in March 2000. Sequencing of the HCV-E1 region (411-bp) and phylogenetic-tree analysis showed near identity between HCV isolates derived from these patients and a haemodialysis patient who was known to be HCV-positive. The mode of transmission could not be conclusively established, but retrospective analysis suggested that the sharing of contaminated multidose vials of heparin-saline solutions, which were prepared in the Haemodialysis Center using accidentally contaminated instruments such as needles, may have been responsible for the outbreak. To prevent transmission of HCV in a haemodialysis unit, it may be important to observe strictly standard precautions and to prepare all medications in the Pharmacy. After these measures were taken, no new seroconversions and no new nosocomial transmissions of HCV have been observed in our haemodialysis unit.

Pharmacokinetics, toxicokinetics, distribution, metabolism and excretion of linezolid in mouse, rat and dog

1. Linezolid (ZYVOX), the first of a new class of antibiotics, the oxazolidinones, is approved for treatment of Gram-positive bacterial infections. 2. The aim was to determine the absorption, distribution, metabolism and excretion (ADME) of linezolid in mouse, rat and dog in support of preclinical safety studies and clinical development. 3. Conventional replicate study designs were employed in animal experiments, and biofluids were assayed by HPLC or HPLC-MS. 4. Linezolid was rapidly absorbed after p.o. dosing with an p.o. bioavailability of > 95% in rat and dog, and > 70% in mouse. Twenty-eight-day i.v./p.o. toxicokinetic studies in rat (20-200mg kg(-1) day(-1)) and dog (10-80 mg kg(-1) day(-1)) revealed neither a meaningful increase in clearance nor accumulation upon multiple dosing. 5. Linezolid had limited protein binding (<35%) and was very well distributed to most extravascular sites, with a volume of distribution at steady-state (V(ss)) approximately equal to total body water. 6. Linezolid circulated mainly as parent drug and was excreted mainly as parent drug and two inactive carboxylic acids, PNU-142586 and PNU-142300. Minor secondary metabolites were also characterized. In all species, the clearance rate was determined by metabolism. 7. Radioactivity recovery was essentially complete within 24-48 h. Renal excretion of parent drug and metabolites was a major elimination route. Parent drug underwent renal tubular reabsorption, significantly slowing parent drug excretion and allowing a slow metabolic process to become rate-limiting in overall clearance. 8. It is concluded that ADME data were relatively consistent across species and supported the rat and dog as the principal non-clinical safety species.

EXAFS study of crystal structures of (Ba1-xLax)2In2O5+x and their oxide ion conductivity

Crystal structures of(Ba1-xLax)2In2O5+x (x=0.00, 0.20, 0.30, 0.40, 0.50) were analyzed by EXAFS and the powder X-ray Rietveld method. A Fourier transform of In K-edge EXAFS data from (Ba1-xLax)2In2O5+x showed a peak between 1.2 and 2.0 A attributed to the nearest oxide ions around In3+ cation. The peak as back-Fourier transformed, and the structural parameters were refined by the least square fitting. The coordination number of In3+ cation increases with increasing La3+ cation) content. This means oxygen is introduced at interstitial site by keeping an electroneutrality. As a result of the oxygen distribution, the oxide ion vacancies distribute randomly. The electrical conductivities of (Ba1-xLax)2In2O5 rapidly increased above 1203 K due to the order-disorder transition of oxygen vacancy. On the other hand, the electrical conductivities of (Ba1-xLax)2In2O5+x (x=0.20, 0.30, 0.35. 0.40, 0.45, 0.50) did not show the sharp discontinuity in the conductivity because the disorder phase of defective perovskite type structure was stabilized by doping La3+ cations at A-site even at low temperature.

Lack of interaction between bropirimine and 5-fluorouracil on human dihydropyrimidine dehydrogenase

1. Bropirimine (2-amino-5-bromo-6-phenyl-4-pyrimidinone) is a member of a class of antineoplastic agents that are administered concomitantly or sequentially with anticancer 5-fluorouracil (5-FU) prodrugs in clinical patients. Interactions between bropirimine and 5-fluorouracil (5-FU) were investigated on dihydropyrimidine dehydrogenase (DPD) activity, the rate-limiting enzyme of 5-FU metabolism, in human liver cytosol. Apparent DPD activity was determined by measuring the recovery of [14C]5-FU by HPLC. 2. The apparent activity of 5-FU metabolism (2.1-100 microM) showed a linear relationship in the Eadie-Hofstee plot in the pooled cytosol, suggesting that a single enzyme is responsible for apparent 5-FU metabolism. Km and Vmax were estimated to be 23 microM and 0.32 nmol min(-1) mg(-1) protein, respectively. Apparent DPD activity for 5-FU (25 microM) in the cytosol from 12 individual donors ranged from 0.017 to 0.39 (0.16 +/- 0.12) nmol min(-1) mg(-1) protein, indicating a large intersubject variance. 3. The suicidal inactivators of the DPD enzyme, (E)-5-(2-bromovinyl)uracil and 5-bromouracil (6.3-50 microM), illustrated concentration-dependent inhibition on DPD activity. Isocytosine (6.3-100 microM), used as a negative control, did not affect DPD activity. Bropirimine (6.3-100 microM) also did not show any inhibition of DPD activity. Therefore, bropirimine is unlikely to cause increases in 5-FU levels in clinical patients after co-administration of bropirimine with 5-FU prodrugs.