Schwannoma mimicking pancreatic carcinoma: A case report

BACKGROUNDSchwannoma of the pancreas is extremely rare. We report a case of pancreatic schwannoma that was difficult to distinguish from pancreatic carcinoma before surgery.CASE SUMMARYA 66-year-old male underwent a right-lobe hepatectomy for hepatocellular carcinoma. Post-surgical computed tomography showed a 10 mm long solid mass with ischemia, with no expansion into the main pancreatic duct. Upon magnetic resonance cholangiopancreatography, the tumor had high signal intensity in diffusion weighted images, consistent with pancreatic carcinoma. Endoscopic ultrasound (EUS) was performed to obtain more information about the tumor, and showed a 14 mm solid and hypoechoic mass in the pancreatic body. Contrast enhanced EUS revealed that the tumor showed a hyperechoic mass in the early phase, and the contrasting effect continuation was very short; findings also consistent with pancreatic carcinoma. Thus, we preoperatively diagnosed his condition as a pancreatic carcinoma and performed distal pancreatectomy with splenectomy. Microscopic examination showed that the tumor was in fact a benign schwannoma. Histology showed a proliferation of spindle-shaped cell in a vague fascicular and haphazard pattern, with palisading arrangement.CONCLUSIONSchwannoma of the pancreas is very rare, however, clinicians should consider schwannoma as the differential diagnosis for pancreatic tumors.     

Pharmacokinetics of 4′-cyano-2′-deoxyguanosine,a novel nucleoside analog inhibitor of the resistant hepatitis B virus,in a rat model of chronic kidney disease

IntroductionThe novel nucleoside analog, 4′-cyano-2′-deoxyguanosine (CdG), possesses inhibitory activity against both the wild-type and resistant hepatitis B virus. Since the dosage of the currently available nucleoside analog preparations needs to be adjusted, depending on renal function, we investigated the effect of renal dysfunction on the pharmacokinetics of CdG in a rat model of chronic kidney disease (CKD).MethodsCKD model rats were either intravenously or orally administered CdG at a dose of 1 mg/kg. The concentration of CdG in plasma, organs (liver and kidney) and urine samples were determined by means of a UPLC system interfaced with a TOF-MS system.ResultsFollowing intravenous administration, the plasma retention of CdG was prolonged in CKD model rats compared to healthy rats. In addition, the clearance of CdG was well correlated with plasma creatinine levels in CKD model rats. Similar to the results for intravenous administration, the plasma concentration profiles of CdG after oral administration were also found to be much higher in CKD model rats than in healthy rats. However, the results for the organ distribution and urinary excretion of CdG, the profiles of which were similar to that of healthy rats, indicated that CdG did not accumulate to a significant extent in the body.ConclusionThe extent of renal dysfunction has a direct influence on the pharmacokinetics (plasma retention) of CdG without a significant accumulation, indicating that the dosage of CdG will be dependent on the extent of renal function. .     

Effect of tryptophan residues on gold mineralization by a gold reducing peptide

AuBP1, obtained by phage display selection, was previously shown to produce gold nanoparticles without reducing agents. The tryptophan (Trp) residue located at the N-terminus of this peptide contributes to the reduction of Au³⁺ to Au⁰ and is involved in the nucleation and crystal growth of gold nanoparticles. However, clear guidelines for relationships between the number of Trp residues in the peptide and its gold reducing ability have not been established. We focused on gold mineralization and attempted to elucidate aspects of the underlying mechanism. We performed a detailed evaluation of the effects of modifying the N-terminus of the core sequence on gold mineralization without reducing agents. Besides, advantages of utilizing peptides in manufacturing gold nanoparticles are shown. UV-Vis measurements, TEM observations, and kinetic analyses were used to show that increasing the number of Trp residues in the peptide increases the reducing ability, causing predominance of the nucleation reaction and the production of small gold nanoparticles. In addition, these peptides also had the ability as a dispersant to protect the surface of gold nanoparticles. Furthermore, the catalytic activity of mineralized gold nanoparticles with peptides was higher than that of a commercial gold nanoparticle. This study should help to elucidate the relationship between peptide sequence and mineralization ability for use in materials chemistry.

Increasing the number of tryptophan (Trp) in peptides led to higher gold reducing ability and the peptides could disperse the generated gold-nanoparticles.     

The Use of a Circular Side Stapling Technique in Laparoscopic Low Anterior Resection for Rectal Cancer: Experience of 30 Serial Cases

The double-stapling technique using a circular stapler (CS) to create an end-to-end anastomosis is currently used widely in laparoscopic-assisted rectal surgery. However, a high rate of anastomotic failure has been reported. We report new side-to-side anastomosis creation using a CS, the so-called circular side stapling technique (CST). After excising the rectum at the oral and anal sides of the tumor with a linear stapler, a side-to-side colorectal anastomosis was made on the anterior wall of the rectosigmoid colon and the anterior or posterior wall of the rectum with a CS. Between 2012 and 2013, we recorded 30 serial cases of rectal-sigmoid or rectal cancer that were treated with laparoscopic-assisted surgeries using this method. In the 30 cases, the mean age was 68 ± 12 years, operating time was 288 ± 80 minutes, and blood loss was 66 ± 67 mL. None of the patients suffered from anastomosis leakage or postoperative anastomotic bleeding, and none complained of their stool habits. Three months after the last surgery in this cohort, no anastomosis strictures were reported. Based on these results, we propose an alternative method of side-to-side anastomosis for low anterior resection by using a CS to prevent staple overlap. Our experience indicates that the CST is easy and safe. Therefore, this method is a useful alternative to the current method used in laparoscopic surgery.Key words: Laparoscopy, Circular stapler, Colorectal cancer, Low anterior resectionLaparoscopic surgery for the treatment of colorectal disease has proven to be a safe and effective method compared with an open procedure.^1–3 Laparoscopy has the advantages of reduced blood loss, hospital stay, and use of anesthetics as well as a better cosmetic outcome. Although many clinical studies have demonstrated the advantages and low complication rates of laparoscopic colectomy and low anterior resection,^1–5 a high rate of anastomotic leakage has been reported in laparoscopic rectal surgeries. The reported incidence of leakage after laparoscopic surgery for the treatment of rectum varies from 6% to 17%.^1–3 Additionally, anastomotic leakage might raise concerns about local recurrence and may limit the patients prognosis.^6–8 Therefore, despite great advances in laparoscopic surgery, the risks of anastomotic complications persist to a greater extent than those for other colonic resections.^6,7Recent reports have included proposed methods for reducing anastomotic leakage, and recently a transanal drainage tube has been recommended, because the high pressure experienced in the rectum could cause anastomotic failure.⁹ Another group reported the use of anti-traction sutures supporting the anastomosis to reduce anastomotic leakage.¹⁰ Despite these proposals, anastomotic failure has not been completely resolved.In typical laparoscopic rectal surgery, a double-stapling technique (DST) with a circular stapler is used to create the anastomosis. This method is thought to be the only method available to complete an intracorporeal anastomosis of the rectum. However, the DST requires the excision of the stump of the staple line created by the linear stapler. Our previous endoscopic experience with anastomotic leakage shows that leakage occurs frequently at the point where the staples overlap in the DST.¹¹ In this study we demonstrate a new circular side stapling technique (CST), which does not require the excision of the linear staple line in a laparoscopic low anterior resection.     

Early effects of lafutidine or rabeprazole on intragastric acidity: which drug is more suitable for on-demand use?

Background Medication for the relief of heartburn should have the rapid onset of action required for on-demand use. We studied the inhibition of gastric acid secretion by lafutidine and rabeprazole, given in single doses to fasting and postprandial subjects.Methods A total of 22 healthy male, Helicobacter pylori-negative volunteers participated in this randomized, two-way crossover study. They were randomly assigned to receive a single oral dose of 10mg lafutidine or 20mg rabeprazole after fasting overnight (12 subjects, fasting study) or after eating a test meal (noodles, 364kcal; protein, 10.1g; fat, 16g; carbohydrates, 44.9g; NaCl, 1.1g; 10 subjects, postprandial study). Intragastric pH was monitored continuously for 6h after treatment. The other drug was given after a washout period of at least 7 days, and intragastric pH was similarly monitored.Results In the fasting study, lafutidine sustained pH at >3 and >4 during the second, third, fourth, fifth, and sixth hours of the study for significantly longer than rabeprazole. During the first 6h after treatment, lafutidine sustained pH at more than 2, 3, 3.5, 4, 5, 6, and 7 longer than rabeprazole. In the postprandial study, lafutidine sustained pH >3 and >4 for longer periods than rabeprazole during the third, fourth, fifth, and sixth hours of the study. During the first 6h after treatment, lafutidine sustained pH at more than 2, 3, 3.5, 4, 5, 6, and 7 longer than rabeprazole.Conclusions Lafutidine 10mg produces a prompter rise in intragastric pH than rabeprazole 20mg in fasting and postprandial Helicobacter pylori-negative male subjects.     

Sofosbuvir plus ribavirin in Japanese patients with chronic genotype 2 HCV infection: an open‐label,phase 3 trial

Genotype 2 hepatitis C virus (HCV) accounts for up to 30% of chronic HCV infections in Japan. The standard of care for patients with genotype 2 HCV – peginterferon and ribavirin for 24 weeks – is poorly tolerated, especially among older patients and those with advanced liver disease. We conducted a phase 3, open‐label study to assess the efficacy and safety of an all‐oral combination of the NS5B polymerase inhibitor sofosbuvir and ribavirin in patients with chronic genotype 2 HCV infection in Japan. We enrolled 90 treatment‐naïve and 63 previously treated patients at 20 sites in Japan. All patients received sofosbuvir 400 mg plus ribavirin (weight‐based dosing) for 12 weeks. The primary endpoint was sustained virologic response at 12 weeks after therapy (SVR12). Of the 153 patients enrolled and treated, 60% had HCV genotype 2a, 11% had cirrhosis, and 22% were over the aged 65 or older. Overall, 148 patients (97%) achieved SVR12. Of the 90 treatment‐naïve patients, 88 (98%) achieved SVR12, and of the 63 previously treated patients, 60 (95%) achieved SVR12. The rate of SVR12 was 94% in patients with cirrhosis and in those aged 65 and older. No patients discontinued study treatment due to adverse events. The most common adverse events were nasopharyngitis, anaemia and headache. Twelve weeks of sofosbuvir and ribavirin resulted in high rates of SVR12 in treatment‐naïve and previously treated patients with chronic genotype 2 HCV infection. The treatment was safe and well tolerated by patients, including the elderly and those with cirrhosis.