Role of Multichance Fission in the Description of Fission-Fragment Mass Distributions at High Energies

Fission-fragment mass distributions were measured for ^{237-240}U, ^{239-242}Np, and ^{241-244}Pu populated in the excitation-energy range from 10 to 60 MeV by multinucleon transfer channels in the reaction ^{18}O+^{238}U at the Japan Atomic Energy Agency tandem facility. Among them, the data for ^{240}U and ^{240,241,242}Np were observed for the first time. It was found that the mass distributions for all the studied nuclides maintain a double-humped shape up to the highest measured energy in contrast to expectations of predominantly symmetric fission due to the washing out of nuclear shell effects. From a comparison with the dynamical calculation based on the fluctuation-dissipation model, this behavior of the mass distributions was unambiguously attributed to the effect of multichance fission.

Esophageal anthracosis with tuberculous lymphadenitis confirmed on transesophageal endoscopic ultrasound-guided fine-needle aspiration

Esophageal anthracosis with tuberculous lymphadenitis is a very rare disease. Almost all reported cases are diagnosed using multiple endoscopic biopsies or thoracic esophagectomy. The present case report describes a case of esophageal anthracosis with tuberculous lymphadenitis that was diagnosed using transesophageal endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) alone. After taking antituberculosis drugs, the patient's chest pain was relieved and she recovered. The patient achieved an excellent outcome following the use of less invasive methods than mediastinoscopy. If no esophageal anthracotic lesions are found on the mucous membrane layer of the esophagus, transesophageal endoscopic ultrasound-guided fine-needle aspiration is a suitable approach for diagnosing esophageal anthracosis.

How many cytological examinations should be performed for the diagnosis of malignant biliary stricture via an endoscopic nasobiliary drainage tube?

BACKGROUND AND AIM

The sensitivity of bile cytology is recognized as being low. Repeating cytological sampling is likely to improve the sensitivity. The aim of this study is to determine the optimal number of repeated cytological sampling of bile obtained via an endoscopic nasobiliary drainage (ENBD) tube for the diagnosis of malignant biliary stricture.

METHODS

Ninety-eight patients with malignant biliary stricture who underwent ENBD were enrolled. Diagnoses included bile duct carcinoma (n = 53), pancreatic carcinoma (n = 28), carcinoma of the major papilla (n = 8), gallbladder carcinoma (n = 6), and hepatocellular carcinoma (n = 3). Bile was aspirated via an ENBD tube once a day and immediately evaluated cytologically.

RESULTS

The median number of cytological samplings via an ENBD tube was 2.8 times (range, 1-10). In 40 of 98 patients with malignant biliary stricture, cytology was positive at the first cytological sampling (sensitivity 40.8%). Cytology was cumulatively positive in 71 of 98 patients (sensitivity 72.4%) from which repeated samples were taken. In 71 patients with positive cytology, correlation of the positive rate and the number of cytological samplings performed was investigated. In 68 of 71 (95.8%) patients with positive cytology, positive results were obtained by or at the sixth examination.

CONCLUSIONS

Bile cytology via an ENBD tube is an easy method, and has been shown to have relatively high sensitivity. The optimal number of repeated cytological samplings using bile obtained via an ENBD tube for the diagnosis of malignant biliary stricture was concluded to be six.

Utility of pancreatic duct brushing for diagnosis of pancreatic carcinoma

BACKGROUND

The aim of this study was to evaluate the usefulness of pancreatic duct brushing for diagnosis of pancreatic carcinoma.

METHODS

Brush cytology was attempted in 58 patients suspected of having pancreatic malignancy because of stricture of the main pancreatic duct, confirmed by endoscopic retrograde cholangiopancreatography. Thirty-eight patients were finally diagnosed by an operation or the clinical course as having pancreatic carcinoma, and the remaining 20 patients as having chronic pancreatitis. The usefulness of brush cytology for diagnosis of pancreatic carcinoma was estimated. We interpreted failures of pancreatic duct brushing to be false negatives when the lesion was malignant.

RESULTS

In 48 of 58 patients (82.8%), brushing was successfully performed and satisfactory specimens were obtained. Brush cytology was positive in 25 of 38 patients with pancreatic carcinoma (sensitivity 65.8%) and negative in all patients without malignancy (specificity 100%). Overall accuracy was 76.4%. During 2001-2005, the number of back-and-forth motions of the brush was increased to more than 30 times. The sensitivity significantly improved from 43.8% in 1997-2000 to 81.8% in 2001-2005 (P < 0.05). The increased success rate of brushing by improvement of skill in manipulating the guidewire and increased number of cells smeared on glass slides by increased back-and-forth motion of the brush may account for this improvement over time. Moreover, the sensitivity in 2001-2005 was 85.7% if failures of brushing with pancreatic carcinoma are excluded. No major complications occurred, except for two patients with a moderate grade of acute pancreatitis.

CONCLUSIONS

Although further studies with a large number of patients are needed, our results suggest that with recent improvements of the brushing technique, pancreatic duct brushing is a useful and safe method for the differential diagnosis of malignancy from benign diseases of the pancreas.

Usefulness of single and repetitive percutaneous transhepatic gallbladder aspiration for the treatment of acute cholecystitis

BACKGROUND

The aim of this study was to evaluate the safety and usefulness of single and repetitive percutaneous transhepatic gallbladder aspiration (PTGBA) for the treatment of acute cholecystitis.

METHODS

PTGBA was performed in patients with acute cholecystitis who showed no improvement after treatment with broad-spectrum antibiotics. PTGBA was carried out at bedside. When the bile was too thick to be aspirated through a 21-gauge needle, an 18-gauge needle was used. Aspiration of the gallbladder contents and injection of antibiotics into the gallbladder were performed without the placement of a drainage catheter. When improvement was not observed after the first attempt, PTGBA was repeated.

RESULTS

Single PTGBA achieved improvement in 32 of 45 patients. In 11 of the remaining 13 patients, the second PTGBA was effective. In the remaining two patients, repetitive PTGBA was not carried out because of advanced cancer. In two of 45 patients, 18-gauge needles were necessary for PTGBA because of the high viscosity of the bile. PTGBA was carried out in three patients with blockage of the cystic duct by a stent, and it was effective in all three. Two patients whose conditions improved with a single PTGBA experienced a recurrence at 4 and 31 months, respectively, after PTGBA. No other severe complications related to PTGBA were observed in any patients.

CONCLUSIONS

For the treatment of acute cholecystitis that does not react to conservative therapies, PTGBA is a safe, simple, and effective treatment modality that can be performed at bedside without any severe complications.

Pre-cutting using a noseless papillotome with independent lumens for contrast material and guidewire

BACKGROUND

The technical success of therapeutic endoscopic retrograde cholangiopancreatography (ERCP) depends on selective cannulation into the bile duct. We have developed a new type of precut papillotome for selective cannulation.

METHODS

The newly developed precut papillotome has been equipped not only with a lumen for contrast materials but also with an independent lumen for the guidewire. The operation of the guidewire and the injection of contrast material can be carried out simultaneously. The precut papillotome has a 20-mm-long knife and no leading tip. Half the proximal side of the knife is coated for insulation.

RESULTS

Selective biliary cannulation failed in 26 of 293 patients (8.9%) in whom therapeutic ERCP was attempted. We applied the precut papillotome to these 26 patients and selective cannulation was successful in 24 of 26 patients (success rate: 92.3%). No major complications occurred, although mild bleeding, which did not require endoscopic hemostasis or blood transfusion, was observed only in one patient.

CONCLUSIONS

Although further studies with a large number of patients are needed to evaluate the efficacy of the papillotome, this papillotome may contribute to increase the safety and the success rate of precutting.

Estimation of the stent placement above the intact sphincter of Oddi against malignant bile duct obstruction

BACKGROUND

In endoscopic biliary stenting against malignant biliary obstruction, stent blockage remains as an important problem. Stent blockage occurs as a result of bacterial adherence to the inner wall of the stent. We evaluated the stent placement above the intact sphincter of Oddi to retain the function of the sphincter of Oddi as a bacteriological barrier.

METHODS

Sixteen patients with malignant biliary obstruction were assessed as the patients with the stent above the intact sphincter of Oddi. Sixteen patients with malignant biliary obstruction were assessed as the patients with the conventional stent placement across the sphincter of Oddi. Tannenbaum 10-Fr. stents were used in both the groups.

RESULTS

The median patency periods of the stent were 255 days (25th to 75th percentiles, 212-454 days; range, 39-454 days) for the group of the stents placed above the sphincter of Oddi and 82 days (25th to 75th percentiles, 48-131 days; range, 22-196 days) for the group of the stents placed across the sphincter of Oddi, respectively, with significant difference (P = 0.0001). The occlusion rates of stents placed above and across the sphincter of Oddi were 37.5% and 93.8%, respectively, with significant difference (P = 0.0008). The dislocation rates of the stent were 0% and 6.3%, respectively (not significant).

CONCLUSIONS

Placement of the stent above the intact sphincter of Oddi was associated with longer stent patency and lower occlusion rate.

Combination of assay of human telomerase reverse transcriptase mRNA and cytology using bile obtained by endoscopic transpapillary catheterization into the gallbladder for diagnosis of gallbladder carcinoma

OBJECTIVES

It is difficult to make accurate diagnoses of polypoid lesions in the gallbladder. To increase the diagnostic accuracy, we have developed an endoscopic technique to obtain gallbladder bile, termed endoscopic transpapillary catheterization into the gallbladder (ETCG). We evaluated the usefulness of a molecular biological approach to the diagnosis of gallbladder carcinoma, in which gallbladder bile obtained by the ETCG technique is used.

METHODS

Twenty patients undergoing an operation because of suspicion of gallbladder carcinoma were enrolled. Twelve patients were confirmed to have gallbladder carcinoma, and four were found to have chronic cholecystitis. Two patients with polypoid lesion were diagnosed as having an inflammatory polyp and a hyperplastic polyp, respectively. The remaining two patients with polypoid lesions were diagnosed as having a cholesterol polyp. Gallbladder bile collected by the ETCG technique was evaluated cytologically and also analyzed for telomerase activity and mRNA for human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase. In 14 patients, hTERT mRNA in resected specimens (fixed in 10% formalin and embedded in paraffin) was also examined.

RESULTS

Cytology of gallbladder bile was positive in eight of 11 examined patients (72.7%) with gallbladder carcinoma. hTERT mRNA was detectable in gallbladder bile as well as in resected neoplastic tissues in four of 12 patients (33.3%) with carcinoma. Conversely, telomerase activity was negative in all eight examined patients with carcinoma. Overall, either cytology or hTERT mRNA of gallbladder bile was positive in 10 of 12 patients (83.3%) with gallbladder carcinoma. Cytology, hTERT mRNA, and telomerase activity were negative in eight patients with benign disease.

CONCLUSIONS

The combination of cytology and hTERT mRNA analysis of gallbladder bile might be helpful for the preoperative diagnosis of gallbladder carcinoma.