Treatment of hepatocellular carcinoma with a portal vein tumor thrombus and pulmonary metastases of rectal cancer with microsatellite stability using atezolizumab plus bevacizumab.

Herein, we report the successful treatment using atezolizumab plus bevacizumab of a patient with hepatocellular carcinoma (HCC) with a portal vein tumor thrombus and multiple pulmonary metastases from rectal cancer with microsatellite stability. This patient developed rectal cancer with synchronous pulmonary metastases and HCC. After resecting the primary lesion of the rectal cancer, transcatheter arterial chemoembolization was performed for the HCC. Drug therapy was planned for multiple pulmonary metastases of rectal cancer; however, the early development of recurrent HCC with portal vein tumor thrombus had to be highly prioritized, and atezolizumab plus bevacizumab was introduced. Following the disappearance of the recurrent HCC lesion, the metastatic pulmonary nodules shrunk into scar-like spots. The treatment for both HCC and pulmonary metastases of rectal cancer were considered to result in clinical complete response.

[An anatomical case of obstructive jaundice due to the rapid enlargement of hepatic peribiliary cysts in end-stage alcoholic liver cirrhosis].

A man in his 60s had end-stage alcoholic cirrhosis. About six months before his death, hepatic peribiliary cysts (HPBC) rapidly increased, and he developed jaundice and liver failure. The pathological autopsy performed after his death revealed that his intrahepatic bile duct was pressured due to multiple cysts caused by HPBC, which resulted in liver failure. Some cases of HPBC have been associated with alcoholic cirrhosis;however, no other cases of increased HPBC in a short period of time have been reported. Although identifying the cause of increased HPBC in a short time is difficult in this case, it may be have been caused by continuous alcohol drinking after the onset of HPBC. Most patients with HPBC have liver cirrhosis and obstructive jaundice that may promote liver failure as in this case. Therefore, patients with HPBC should not only be instructed for abstinence but also promptly consider effective treatments in the event of obstructive jaundice to prevent liver dysfunction.

Difficult removal of totally implantable venous access devices in adult patients: Incidence, risk factors, and management.

BACKGROUND: Totally implantable venous access devices (TIVADs) have played an important role of medical oncology practice. However, operators sometimes encounter considerable difficulty when removing TIVADs. This study aimed to investigate the incidence of difficult TIVAD removal, determine associated risk factors, and investigate interventional radiology (IR) approaches to difficult removal. METHODS: A total of 514 TIVAD removal procedures performed in a single-center between January 2014 and May 2021 were retrospectively analyzed to determine incidence of difficult removal and associated risk factors. IR approaches applied in difficult removal cases were also reviewed. RESULTS: The incidence of difficult removal was 7.4% (38/514). In univariable analysis, indwelling duration, silicone catheter, and subcutaneous leakage of fluid were identified as significant risk factors for difficult removal. Multivariable analysis showed that indwelling duration per year (odds ratio (OR), 1.46; 95% confidence interval (CI), 1.28-1.67; p < 0.01) and subcutaneous leakage of fluid (OR, 6.04; 95% CI, 2.45-14.91; p < 0.01) were significantly associated with difficult removal. In the 38 difficult removal cases, 32 TIVADs could be removed using more dissection and traction than the standard removal method. In the other 6, TIVADs were successfully removed by using several IR techniques, including insertion of a guide wire (n = 1), dissection using an introducer sheath (n = 2), pushing with a dilator (n = 1), and pulling with a snare (n = 2). CONCLUSION: Difficult TIVAD removal is uncommon. However, operators should expect it when removing long indwelling TIVADs and those with subcutaneous leakage. IR approaches to difficult removal are minimally invasive and can be useful.

Clinical usefulness of Somatostatin Receptor Scintigraphy in the Diagnosis of Neuroendocrine Neoplasms.

OBJECTIVES: We investigated the detectability of somatostatin receptor scintigraphy (SRS) for neuroendocrine neoplasms (NEN). METHODS: From January 2016 to October 2020, 125 SRS examinations using indium-111 pentetreotide performed for patients with NEN lesions were retrospectively evaluated. The detection rate of NEN lesions was determined according to histopathological classification by primary site and by organ. RESULTS: At least one NEN lesion was detected in 73% (91/125) with a positive Krenning score of ≥2 in SRS. The detection of abdominal NENs (gastrointestinal tract, 38; pancreas, 62; and others, 14) was 89% (49/55) for neuroendocrine tumor (NET)-grade (G) 1, 78% (32/41) for NET-G2, 66% (2/3) for NET-G3, 31% (4/13) for neuroendocrine carcinoma (NEC), 100% (1/1) for mixed neuroendocrine-non-neuroendocrine neoplasm, and 0% (0/1) for non-classified NEN. That of thoracic NENs was 33% (2/6) for typical carcinoid tumor and 40% (2/5) for atypical carcinoid tumor. For a total of 226 organ lesions, hepatic lesions were 76% (58/76); pancreatic lesions, 61% (31/51); lymph node lesions, 77% (27/35); bone lesions, 83% (20/24); duodenal lesions, 82% (9/11); and other lesions, 41% (11/27). CONCLUSION: The detectability of SRS for NEN in Japan was verified at a center, and its usefulness was confirmed.

Stenting Using the Rendezvous Technique for Postoperative Ureteral Complications in Cancer Patients.

PURPOSE: This study aimed to retrospectively evaluate the safety and efficacy of ureteral stent placement using the rendezvous technique for the treatment of postoperative ureteral complications in cancer patients. MATERIALS AND METHODS: From January 2005 to April 2015, 19 patients (2 men and 17 women; median age, 59; range, 42-79 years old) with unilateral ureteral lesions (ureteral leakages in 6, strictures in 4, and both in 9) underwent ureteral stent placement using the rendezvous technique. Percutaneous nephrostomy was performed, and stent placement was attempted via antegrade and retrograde approaches. The technical success, procedure-related complications, and clinical success were retrospectively analyzed. RESULTS: The median follow-up period was 29.8 months (range, 0.3-116.5 months). The ureteral stent placement was successful in 17 out of 19 patients (89.5%). Double J ureteral stent was used in 6 patients, and straight catheter as an internal-external nephro-ureteral stent was used in 11 patients. The rendezvous technique was used in the retroperitoneal space and urinary tract in 6 and 11 patients, respectively. No major complications related to the rendezvous technique occurred. Finally, 4 patients achieved stent-free condition (21.1%), and periodic stent exchange was continued in 9 (47.4%). However, permanent external drainage and surgical reconstruction were needed in 4 (21.1%) and 2 (10.5%) patients, respectively. The final clinical success rate was 68.4% (13 out of 19 patients). CONCLUSION: Ureteral stent placement using the rendezvous technique for the treatment of postoperative ureteral complications in cancer patients is safe and may be alternative to permanent external drainage and invasive surgical reconstruction. LEVEL OF EVIDENCE: Level 4, Case series.

Clinical Outcomes and Techniques for Radiofrequency Ablation of Lung Tumors Smaller than 1 cm.

Purpose: To evaluate the outcomes of radiofrequency ablation (RFA) on lung tumors < 1 cm in maximum diameter. Materials and Methods: Twenty-eight patients (12 male, 16 female; median age, 59 years; mean age, 58 ± 16 years; range, 16-78 years) who underwent RFA for lung tumors < 1 cm in diameter between November 2009 and September 2018 were included in this study. Thirty-five tumors (median size, 8.4 mm; mean size, 7.7 ± 1.9 mm; range, 3.6-9.9 mm) were treated with 33 sessions of RFA. Technique efficacy and safety were subsequently evaluated. Initial and secondary technique efficacy were defined as complete ablation without residual tumor or local tumor progression after initial and repeat RFA, respectively. Safety was evaluated according to the Common Terminology Criteria for Adverse Events, version 5.0. Results: Residual tumor remained for 1 tumor (3%, 1/35) and local tumor progression was found in 2 tumors (6%, 2/35). Initial technique efficacy rate was therefore 91% (32/35). The remaining 3 tumors were treated by repeat RFA (secondary technique efficacy rate: 100%, 35/35). Initial technique efficacy rate was significantly lower for tumors treated with starting energy ≥ 20 W (P = 0.02) and showing a quick increase in tissue impedance (P = 0.01). There were 4 grade 2 adverse events (12%, 4/33) comprising pneumothorax requiring chest tube placement, and 14 grade 1 adverse events comprising self-limiting pneumothorax (36%, 12/33) and pulmonary parenchymal hemorrhage (6%, 2/33). Conclusion: To achieve good outcomes for lung tumors < 1 cm, radiofrequency energy should be started at < 20 W. Application of manual mode ablation might be considered when delivery of power cannot be continued due to a quick increase in tissue impedance.

Management of acute cholecystitis after biliary stenting for malignant obstruction: comparison of percutaneous gallbladder drainage and aspiration.

PURPOSE: To evaluate and compare the clinical outcomes between percutaneous gallbladder drainage (PGBD) and percutaneous gallbladder aspiration (PGBA) for acute cholecystitis after biliary stenting for malignant biliary obstruction. MATERIALS AND METHODS: Twenty-six and 14 patients underwent PGBD and PGBA, respectively, for acute cholecystitis after biliary stenting for malignant obstruction. The technical success rate, clinical effectiveness, and safety were compared between the 2 groups. RESULTS: Technical success was achieved in all patients. Clinical effectiveness rate was significantly higher in the PGBD group than in the PGBA group [100% (26/26) vs. 57% (8/14), p < 0.01]. In the PGBA group, clinical effectiveness rate was significantly lower in patients with tumor involvement of the cystic duct [13% (1/8) with involvement vs. 83% (5/6) without involvement, p = 0.03]. There were no deaths related to the procedure or acute cholecystitis aggravation. Pleural effusion and biliary peritonitis occurred in 1 patient each after PGBD and intra-abdominal bleeding occurred in 1 patient after PGBA as complications requiring treatment. CONCLUSION: Although PGBD was a more effective treatment for acute cholecystitis after biliary stenting for malignant obstruction, PGBA may be a less invasive option for high-risk patients without tumor involvement of the cystic duct.

Predicting chemotherapeutic response for colorectal liver metastases using relative tumor enhancement of gadoxetic acid disodium-enhanced magnetic resonance imaging.

PURPOSE: This study aimed to predict the treatment response for colorectal liver metastases (CLM) using relative tumor enhancement (RTE) of the hepatobiliary phase (HBP) for patients with no history of chemotherapy. MATERIALS AND METHODS: In this retrospective study, we enrolled 26 patients [14 males, 12 females; median age: 58 years (range 37-82 years)] with CLM and no history of chemotherapy between December 2011 and May 2017. Gadoxetic acid-enhanced magnetic resonance imaging was performed before starting chemotherapy and RTE of HBP. The response was evaluated using RECIST ver.1.1, and progression-free survival (PFS) was estimated. RESULTS: Based on the RECIST ver.1.1, there were 15 responders and 11 non-responders. In the tumor, the mean pretreatment RTE values were significantly higher in the responders group than in the non-responders group (37.2% ± 10.9% vs. 17.9% ± 10.5%, respectively; P = 0.0006). When the threshold values of parameters for detecting responders comprised the RTE value of 24.2% (area under the curve value, 0.90), the sensitivity and specificity were 93.3% and 72.7%, respectively. The median follow-up period for 26 patients was 602 days (range 160-1971 days). Although no significant differences were observed in PFS between the groups, the high RTE group tended to take longer to progress than the low RTE group (PFS of the high RTE group did not reach the median). CONCLUSION: This study suggests that the RTE value of CLM could be a potential biomarker to predict early treatment response.

Pathologic Diagnosis and Genetic Analysis of a Lung Tumor Needle Biopsy Specimen Obtained Immediately After Radiofrequency Ablation.

PURPOSE: To evaluate the possibility of pathologic diagnosis and genetic analysis of percutaneous core-needle biopsy (CNB) lung tumor specimens obtained immediately after radiofrequency ablation (RFA). MATERIALS AND METHODS: Patients who underwent CNB of lung tumors immediately after RFA from May 2013 to May 2016 were analyzed. There were 19 patients (8 men and 11 women; median age, 69 years; range, 52-88 years) and 19 lung tumors measuring 0.5-2.6 cm (median, 1.6 cm). Thirteen tumors were solid, and 6 were predominantly ground-glass opacity (GGO) on computed tomography. All specimens were pathologically examined using hematoxylin and eosin (H&E) staining and additional immunostaining, as necessary. The specimens were analyzed for EGFR and KRAS genetic mutations. The safety and technical success rate of the procedure and the possibility of pathologic diagnosis and genetic mutation analysis were evaluated. RESULTS: Major and minor complication rates were 11% (2/19) and 53% (10/19), respectively. Tumor cells were successfully obtained in 16 cases (84%, 16/19), and technical success rate was significantly lower for GGO-dominant tumors (50%, 3/6) compared with solid lesions (100%, 13/13, p = 0.02). Pathologic diagnosis was possible in 79% (15/19) of cases based on H&E staining alone (n = 12) and with additional immunostaining (n = 3). Although atypical cells were obtained, pathologic diagnosis could not be achieved in 1 case (5%, 1/19). Both EGFR and KRAS mutations could be analyzed in 74% (14/19) of the specimens. CONCLUSION: Pathologic diagnosis and genetic analysis could be performed even for lung tumor specimens obtained immediately after RFA.

Outcomes of a Phase I/II Trial of Hepatic Arterial Infusion of Oxaliplatin Combined with Intravenous 5-Fluorouracil and l-Leucovorin in Patients with Unresectable Liver Metastases from Colorectal Cancer After Systemic Chemotherapy Failure.

PURPOSE: The purpose of this study was to assess hepatic arterial infusion (HAI) of oxaliplatin combined with intravenous 5-fluorouracil (5-FU) and l-leucovorin (l-LV) in colorectal cancer (CRC) patients with systemic chemotherapy failure in a phase I/II trial. METHODS: CRC patients with unresectable liver metastases following standard systemic chemotherapy failure were eligible. A catheter-port system for HAI was placed using interventional radiology. In phase I, escalating doses of oxaliplatin for levels 1 and 2 were set at 50 and 100 mg/m2, respectively, and were combined with fixed doses of intravenous 5-FU (200 mg/m2 bolus and 2400 mg/m2/46-h continuous infusion) and l-LV (200 mg/m2). The dose-limiting toxicity (DLT) was assessed, and the recommended dose (RD) was estimated. In phase II, patients receiving RD were included to assess the 6-month survival rate (the expected rate 80%), overall survival time, tumor response, and toxicity. RESULTS: In phase I, none of the six enrolled patients exhibited DLT. RD for oxaliplatin by HAI was estimated as 100 mg/m2. In phase II, seven additional patients were enrolled. In patients receiving RD (n = 10), the disease control rates for total lesions and liver lesions were 30 and 70%, respectively. The 6-month survival rate and the overall survival time were 53.3% and 6.9 months, respectively. There were no adverse reactions equivalent to DLT in any of the patients. CONCLUSIONS: The estimated RD for oxaliplatin by HAI in combination with intravenous 5-FU and l-LV was 100 mg/m2. This combination therapy was feasible and safe, but the expected efficacy was not achieved.

Intrahepatic portosystemic venous shunt via the right adrenal vein: treatment with vascular plug.

A 65-year-old man with hepatocellular carcinoma (HCC) due to alcohol-related liver cirrhosis had undergone transarterial chemoembolization 11 times. However, treatment for HCC was difficult to continue, due to episodic hepatic encephalopathy. He was referred to our hospital for treatment of hepatic encephalopathy, showing a Child-Pugh score of 8 despite medical therapy. Abdominal computed tomography revealed intrahepatic portosystemic venous shunt comprising two shunt tracts from the right posterior portal vein to the inferior vena cava via the right adrenal vein. The larger tract was occluded using an Amplatzer Vascular Plug (AVP) II, and the smaller tract was occluded using an original AVP. The postembolization course was uneventful. Hepatic encephalopathy improved after shunt occlusion and no recurrence had occurred as of one year after the procedure.

Safety and short-term outcomes of endoscopic submucosal dissection for early gastric cancer in elderly patients.

BACKGROUND AND STUDY AIMS: Endoscopic submucosal dissection (ESD) has become widely accepted as a minimally invasive treatment for early gastric cancer (EGC), and opportunities to use ESD to treat EGC in elderly patients are increasing. The objective of this study was to elucidate the safety and efficacy of ESD in elderly patients. PATIENTS AND METHODS: Between April 2006 and March 2013, a total of 892 patients with EGC were prospectively recruited to undergo ESD according to definite inclusion criteria. The short-term outcomes and incidence of complications in 345 of these patients who were 75 years of age or older (elderly group) were compared with the short-term outcomes and incidence of complications in the remaining 547 patients (non-elderly group). Factors associated with the occurrence of pneumonia and delirium were also investigated. RESULTS: The R0 resection rate did not differ between the two groups (96.2 % in the elderly group vs. 96.7 % in the non-elderly group; P = 0.65). The incidence of pneumonia (7.5 % vs. 1.8 %; P < 0.01) and incidence of delirium (10.1 % vs. 1.1 %; P < 0.01) were significantly higher in the elderly group. The incidence of post-ESD bleeding and incidence of perforation were similar in the two groups. No emergency surgery was required, but one patient in the non-elderly group died of aspiration pneumonia. On multivariate analysis, age 75 years or older, cerebrovascular disease, chronic obstructive pulmonary disease, delirium, and remnant stomach or gastric tube were independent risk factors for pneumonia, and age 75 years or older, diabetes, dementia, and pneumonia were independent risk factors for delirium. CONCLUSION: ESD for EGC was feasible for elderly patients in good condition. However, pneumonia and delirium may develop more frequently after ESD in elderly patients with co-morbidities.

Diagnostic Ability of Percutaneous Needle Biopsy Immediately After Radiofrequency Ablation for Malignant Lung Tumors: An Initial Experience.

PURPOSE: To evaluate the safety and diagnostic ability of percutaneous needle biopsy performed immediately after lung radiofrequency ablation (RFA). MATERIALS AND METHODS: From May 2013 to April 2014, percutaneous needle biopsy was performed immediately after RFA for 3 patients (2 men and 1 woman, aged 57-76 years) who had lung tumors measuring 1.3-2.6 cm in diameter. All patients had prior history of malignancy, and all tumors were radiologically diagnosed as malignant. Obtained specimens were pathologically classified using standard hematoxylin and eosin staining. RESULTS: We completed three planned sessions of RFA followed by percutaneous needle biopsy, all of which obtained tumor tissue that could be pathologically diagnosed. Two tumors were metastatic from renal clear cell carcinoma and rectal adenocarcinoma, respectively; one tumor was primary lung adenocarcinoma. There was no death or major complication related to the procedures. Although pneumothorax occurred in two patients, these resolved without the need for aspiration or chest tube placement. Tumor seeding was not observed, but 21 months after the procedure, one case developed local tumor progression that was treated by additional RFA. CONCLUSION: Pathologic diagnosis was possible by needle biopsy immediately after RFA for lung tumors. This technique may reduce the risks and efforts of performing biopsy and RFA on separate occasions.

Preoperative estimation of future remnant liver function following portal vein embolization using relative enhancement on gadoxetic acid disodium-enhanced magnetic resonance imaging.

OBJECTIVE: To retrospectively evaluate relative enhancement (RE) in the hepatobiliary phase of gadoxetic acid disodium-enhanced magnetic resonance (MR) imaging as a preoperative estimation of future remnant liver (FRL) function in a patients who underwent portal vein embolization (PVE). MATERIALS AND METHODS: In 53 patients, the correlation between the indocyanine green clearance (ICG-K) and RE imaging was analyzed before hepatectomy (first analysis). Twenty-three of the 53 patients underwent PVE followed by a repeat RE imaging and ICG test before an extended hepatectomy and their results were further analyzed (second analysis). Whole liver function and FRL function were calculated on the MR imaging as follows: RE x total liver volume (RE Index) and FRL-RE x FRL volume (Rem RE Index), respectively. Regarding clinical outcome, posthepatectomy liver failure (PHLF) was evaluated in patients undergoing PVE. RESULTS: Indocyanine green clearance correlated with the RE Index (r = 0.365, p = 0.007), and ICG-K of FRL (ICG-Krem) strongly correlated with the Rem RE Index (r = 0.738, p < 0.001) in the first analysis. Both the ICG-Krem and the Rem RE Index were significantly correlated after PVE (r = 0.508, p = 0.013) at the second analysis. The rate of improvement of the Rem RE Index from before PVE to after PVE was significantly higher than that of ICG-Krem (p = 0.014). Patients with PHLF had a significantly lower Rem RE Index than patients without PHLF (p = 0.023). CONCLUSION: Relative enhancement imaging can be used to estimate FRL function after PVE.

Side-Hole Catheter Placement with Fixation and Embolization in Common Hepatic Artery for Hepatic Arterial Infusion Chemotherapy (Modified CHA-Coil Method) for Patients with Celiac Artery Stenosis or Occlusion.

PURPOSE: We retrospectively assessed the feasibility of a side-hole catheter placement with fixation and embolization in the common hepatic artery (CHA) (modified CHA-coil method) for hepatic arterial infusion (HAI) chemotherapy. MATERIALS AND METHODS: HAI catheter placement was attempted with modified CHA-coil method in five patients with unresectable hepatic malignancies between 2000 and 2013. The reason for using this method, the mode of catheter placement, and the duration of HAI were investigated. RESULTS: All patients had either occlusion or stenosis of the celiac artery (CA) or CHA, and, as a result, CHA blood flow had either reversed or decreased and hepatopetal GDA flow was observed. In three patients, the proper hepatic artery was extremely short. The side-hole catheter was inserted through the left subclavian artery and was placed from CA to the right gastroepiploic artery in an anterograde manner (n = 4) and from the superior mesenteric artery to the splenic artery in a retrograde manner through GDA (n = 1). The side hole of the catheter was positioned at the proximal portion of GDA. Using a separate catheter inserted from the right femoral artery, coils were placed around the indwelling catheter of CHA to embolize CHA and to fix the catheter. Coil mislocation was not observed, and catheter placement was successful in all patients. HAI chemotherapy was administered for a median of 136 days. The catheter displacement was not observed during HAI. CONCLUSION: The modified CHA-coil method can be used as a stable method for catheter placement when CHA is narrow or there is retrograde CHA blood flow.

Percutaneous drainage for afferent limb syndrome and pancreatic fistula via the blind end of the jejunal limb after pancreatoduodenectomy or bile duct resection.

PURPOSE: To investigate the feasibility of percutaneous drainage via the blind end of the jejunal limb (BEJL) for afferent limb syndrome and pancreatic fistula. MATERIALS AND METHODS: Percutaneous drainage via the BEJL was performed in eight patients (seven men and one woman; mean age, 63 y; range, 42-71 y) presenting with afferent limb syndrome (n = 6) or pancreatic fistula (n = 2) following pancreatoduodenectomy or bile duct resection with reconstruction at our institute from March 2005 to June 2013. Reconstruction was performed by using a modified Child method or the Roux-en-Y method, and the BEJL was surgically fixed to the abdominal wall. Afferent limb syndrome was caused by tumor recurrence or postoperative complications. Technical success, clinical success, and complications were evaluated retrospectively. RESULTS: Technical success of drainage via BEJL was achieved in all patients. Drainage catheters (5-10 F) were inserted into the afferent limbs of six patients, into the pancreatic duct of one patient, and into the pancreatic fistula of one patient. Metallic stents were subsequently placed to address malignant afferent limb obstruction in two patients. Clinical success was achieved in seven patients (87.5%), and no patients developed major complications. Drainage catheters were removed from four patients. The mean catheter indwelling period in all patients was 143 days (range, 21-292 d). CONCLUSIONS: Percutaneous drainage via BEJL after pancreatoduodenectomy or bile duct resection may be a feasible treatment for afferent limb syndrome and pancreatic fistula.

Esophageal stenting after penetrating complete esophageal obstruction using a trocar stylet via a gastrostomy route: a case report.

Complete esophageal obstruction developed after radiation and endoscopic submucosal dissection therapy for a cervical esophageal cancer in a 77-year-old woman. After failure to recanalize the esophageal obstruction by endoscopic and catheterization techniques, the esophageal obstruction was penetrated using a trocar stylet needle via a gastrostomy route. A covered stent was placed across the esophageal obstruction, letting her take water and liquid food until she died 2 months later. There was no complication related to the procedures except transient chest discomfort and pain that subsided with symptomatic treatment.

Ring-enhancement pattern on contrast-enhanced CT predicts adenosquamous carcinoma of the pancreas: a matched case-control study.

OBJECTIVES: Adenosquamous carcinoma of the pancreas (ASC) is a rare malignant neoplasm of the pancreas, exhibiting both glandular and squamous differentiation. However, little is known about its imaging features. This study examined the imaging features of pancreatic ASC. METHODS: We evaluated images of contrast-enhanced computed tomography (CT) and endoscopic ultrasonography (EUS). As controls, solid pancreatic neoplasms matched in a 2:1 ratio to ASC cases for age, sex and tumor location were also evaluated. RESULTS: Twenty-three ASC cases were examined, and 46 solid pancreatic neoplasms (43 pancreatic ductal adenocarcinomas, two pancreatic neuroendocrine tumors and one acinar cell carcinoma) were matched as controls. Univariate analysis demonstrated significant differences in the outline and vascularity of tumors on contrast-enhanced CT in the ASC and control groups (P < 0.001 and P < 0.001, respectively). A smooth outline, cystic changes, and the ring-enhancement pattern on contrast-enhanced CT were seen to have significant predictive powers by stepwise forward logistic regression analysis (P = 0.044, P = 0.010, and P = 0.001, respectively). Of the three, the ring-enhancement pattern was the most useful, and its predictive diagnostic sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of ASC were 65.2%, 89.6%, 75.0% and 84.3%, respectively. CONCLUSIONS: These results demonstrate that presence of the ring-enhancement pattern on contrast-enhanced CT is the most useful predictive factor for ASC.

Reconstitution of a sequential reaction of two nitrogenase-like enzymes in the bacteriochlorophyll biosynthetic pathway of Rhodobacter capsulatus.

The parental structure of bacteriochlorophyll a, bacteriochlorin, is formed by a sequential operation of two nitrogenase-like enzymes, dark-operative protochlorophyllide oxidoreductase (DPOR) and chlorophyllide a oxidoreductase (COR). Both DPOR and COR consist of two components, Fe protein and MoFe protein cognates. Here we determined kinetic parameters of COR and established the reconstitution system for the formation of bacteriochlorin (3-vinyl bacteriochlorophyllide a) from porphyrin (protochlorophyllide) with purified components of DPOR and COR from Rhodobacter capsulatus. This reconstitution system confirmed the recent finding that COR catalyzes 8-vinyl reduction of 8-vinyl chlorophyllide a in addition to the known activity of C7C8 double bond reduction, and provides a promising model to investigate how two nitrogenase-like enzymes are coordinated in bacteriochlorophyll biosynthesis.