Non-marine Ostracoda (Crustacea) collected from pet shops and a hobbyists aquaria in Japan, including two new species.

Samples obtained from pet shops and a hobbyists aquaria in Japan have revealed a diverse non-marine ostracod fauna, consisting of 19 species, all contaminants of aquaria stocked with exotic fish, shrimps and/or aquatic plants. Of these, six are newly recorded for Japan, including two new species, belonging to the genera Pseudostrandesia and Tanycypris. Pseudostrandesia tenebrarum Smith & Ozawa, 2021, previously suspected to be an alien species in Japan, was again found in pet shops in this study. We also report living specimens of Potamocypris acuminata Fuhrmann & Goth, 2011, a species previously only known from Pleistocene deposits of Germany. The six new records for Japan reported herein are likely alien species as evidenced by previous records or congeneric species, with origins in East Asia, South East Asia, and the Americas. Thus, there are now seven ostracod species recognized as probable alien hitchhikers in the Japanese pet trade. This study highlights that the pet trade is a viable route for hitchhiking ostracod species to enter Japan, and such species have the potential to become invasive.

A New Species of Pseudostrandesia Savatenalinton and Martens, 2009 (Ostracoda, Crustacea) Collected from Two Pet Shops in Central Japan: an Alien Species?

An undescribed species of freshwater ostracod belonging to the genus Pseudostrandesia Savatenalinton and Martens, 2009 was collected from two pet shops in the Kanto region of central Japan. This species, herein named Pseudostrandesia tenebrarum sp. nov., is similar to four species previously reported from Southeast Asia, but can be distinguished by carapace and appendage features. It is the second species of the genus for which males are known. Of the nine previously described species in the genus, one is exclusively known from Turkey, and the others are found in Southeast Asia and the vicinity, one of which is also recorded in India and east China. There are two scenarios to explain the existence of Pseudostrandesia tenebrarum sp. nov. in pet shops in Japan: it is either native to Japan but has yet to be discovered in its natural habitat, or it is an alien species, perhaps unwittingly imported with plants or fish for the pet trade. We review the likelihood of both scenarios, and conclude that although there is insufficient evidence to be sure, it is potentially an alien species in Japan. The most likely origin is Southeast Asia, as evidenced by its close morphological resemblance to particular Southeast Asian species. Juveniles as well as adults were recovered, indicating that this species is reproducing in the pet trade, supporting the notion that it has invasive potential to areas outside of its natural range. The description and report of this species highlights a possible introduction of an alien species to Japan, and facilitates further monitoring.

Delay of endoscopic submucosal dissection-induced gastric ulcer healing by methotrexate.

We report a case of methotrexate (MTX) delaying the healing of an endoscopic submucosal dissection (ESD)-induced gastric ulcer. The patient, who had been taking MTX for rheumatoid arthritis, underwent ESD for early gastric carcinoma. Despite taking vonoprazan after ESD, abdominal pain and anorexia continued, and the gastric ulcer did not heal after the ESD. After discontinuing MTX, the patient's symptoms improved and the ulcer healed. Patients taking MTX require careful follow-up after ESD, considering that ulcers can be difficult to heal. Discontinuation of MTX should be considered if delayed healing of an ulcer is observed.

[A case of extrahepatic bile duct metastasis from gastric cancer].

A 56-year-old man was admitted with obstructive jaundice. Abdominal computed tomography and endoscopic retrograde cholangiopancreatography showed circumferential stenosis with irregular wall in lower bile duct, but the cytology of biliary brushing was no malignancy. The patient was given a diagnosis of gastric carcinoma with bone and skin metastasis. He died 2 months after the first hospital admission and autopsy was performed. The histological findings of gastric and bile duct tumor revealed signet ring cell carcinoma. The immunohistological findings of both tumors were identical. We definitively diagnosed this case as metastasis of gastric carcinoma to the bile duct.

Usefulness of endoscopic ultrasound-guided fine-needle aspiration biopsy for the diagnosis of pancreatic cancer.

BACKGROUND: Endoscopic ultrasonography-guided fine-needle aspiration biopsy (EUS-FNAB) has come into widespread use, mainly in Western countries, as an efficient and safe method for the cytologic or histologic diagnosis of pancreatic cancer. However, it still has received relatively little attention in Japan. To evaluate the clinical status of EUS-FNAB in Japan, we retrospectively analyzed the results with regard to the ability of EUS-FNAB to diagnose pancreatic cancer, as well as its safety. METHODS: A total of 52 patients (37 male, 15 female; mean age, 62.5 years; range, 33-85 years) with focal pancreatic lesions underwent EUS-FNAB at our group of hospitals in one region of Japan. Final diagnosis was confirmed by histologic examination of surgical specimens or clinical follow-up. RESULTS: The final diagnoses were malignant tumors in 32 patients and benign ones in 20. Insertion of the needle into the lesion was successful in 50 of the 52 patients (96.2%). Adequate specimens were obtained by EUS-FNAB from 47 of the 50 pancreatic lesions (94.0%). With five false-negative and no false-positive results, the accuracy, sensitivity, specificity, and positive and negative predictive values were 89.4%, 82.1%, 100%, 100%, and 79.2%, respectively. No complications occurred. CONCLUSIONS: EUS-FNAB is an efficient and safe method for the histologic diagnosis of pancreatic cancer. It should be considered as one of the indispensable modalities for the histological diagnosis of pancreatic cancer in Japan, as it is in Western countries.

Growth kinetics of Vibrio parahaemolyticus O3:K6 under varying conditions of pH, NaCl concentration and temperature.

The growth responses of Vibrio parahamolyticus to pH, NaCl concentration and temperature changes were studied using serotype O3:K6 and other strains. Growth curves were obtained for 27 different sets of conditions, comprised of three levels of NaCl concentration, pH and temperature. The temperature, pH and NaCl concentrations most favorable for growth were in the order of 25 degrees C, 20 degrees C and 15 degrees C, pH 8, 7 and 5.8, and 1%, 3% and 7%, respectively. The bacteria grew most rapidly at 25 degrees C, at a pH of 7 or 8 in the presence of 1% or 3% NaCl, with the population (initial, ca. 2.5 log CFU/mL) reaching a level log 7 CFU/mL at 12 h. A growth predictive model using the Gompertz equation was generated from the experimental data for any combination of NaCl concentration, pH and temperature within the range used in this study.

Vascular endothelial growth factor-C expression in human gallbladder cancer and its relationship to lymph node metastasis.

Lymph node metastasis is a major prognostic factor in human cancer. Vascular endothelial growth factor C (VEGF-C) is a lymphangiogenic polypeptide that has been implicated in several human solid tumors. However, the clinical significance of VEGF-C has remained unknown in gallbladder carcinoma. Paraffin-embedded tumor specimens of 52 surgically resected gallbladder cancers were immunohistochemically stained for VEGF-C, VEGF, and CD34. The correlations among VEGF-C expression, VEGF expression, microvessel density (MVD), clinicopathologic features, and clinical outcomes were statistically analyzed. Thirty-three (63%) of the 52 gallbladder cancers were highly positive for VEGF-C protein by immunohistochemistry. VEGF-C expression was significantly correlated with lymphatic vessel involvement, lymph node metastasis, and worse outcomes after operation (p<0.001, p<0.001, p<0.001, respectively), but not with MVD. By the Cox regression model, lymphatic vessel involvement emerged as an independent prognostic parameter. These results suggest that VEGF-C may play a role in tumor progression via lymphangiogenesis and lymph node metastasis in human gallbladder cancer.