Out of the ancient lake: Multiple riverine colonizations and diversification of the freshwater snails in the genus Semisulcospira around Lake Biwa.

Ancient lakes are a hotspot of biodiversity. Freshwater species often experience spectacular species radiation after colonizing lakes from riverine habitats. Therefore, the relationship between the fauna of the ancient lakes and the surrounding riverine system has a special significance in understanding their origin and evolutionary history. The study of ancient lake species often focused on the lake colonization of riverine species. In contrast, far less attention has been placed on the reverse direction: the riverine colonization of the lake species, despite its importance in disentangling their complex evolutionary history. The freshwater snails in the genus Semisulcospira involve endemic groups that radiated in the ancient Lake Biwa. Using genetics and fossil records, we inferred that the ancestors of these lake-endemic Semisulcospira snails historically colonized the riverine habitats at least three times during the Middle Pleistocene. Each colonization resulted in the formation of a new lineage that was genetically and morphologically distinct from other lineages. Further, one of these colonizations was followed by hybridization with a cosmopolitan riverine species, which potentially facilitated the population persistence of the colonizers in the new environment. Despite their complex histories, all these colonizers were currently grouped within a single species, Semisulcospira kurodai, suggesting cryptic diversity in this species. This study highlights the significance of the riverine colonizations of the lake species to fully understand the diversification history of freshwater fauna in and around the ancient lakes.

[Laparoscopic Proximal Gastrectomy with Supra-Pancreatic Dissection First Approach].

BACKGROUND: In laparoscopic proximal gastrectomy(LPG)with esophago-gastro anastomosis, the key of obtaining good surgical view is how to exclude the stomach from the supra-pancreatic area. METHODS: We could get good surgical view at the supra-pancreatic area with gastro-ptosis by firstly dissecting lesser curvature. Followed by the supra-pancreatic dissection we could efficiently dissect the gastro-splenic ligament from cranial side. We performed this procedure in 20 cases with upper gastric cancer. We evaluate the surgical outcomes of this procedure(S group)comparing to that of the previous procedure in 14 cases(G group). RESULTS: The median operative time in S group was significantly shorter than that in G group (226 min vs 249 min, p=0.02). Other data were similar in 2 groups. CONCLUSIONS: The short-term clinical outcomes of LPG with supra-pancreatic dissection first approach revealed that this technique is safe and feasible.

Revisiting a 135-year-old Taxonomic Account of the Freshwater Snail Semisulcospira multigranosa: Designating its Lectotype and Describing a New Species of the genus (Mollusca: Gastropoda: Semisulcospiridae).

The type series of Semisulcospira multigranosa Boettger, 1886 was found in the Malacological Collection at the Senckenberg Naturmuseum for the first time ca. 135 years after its original description. The syntypes consisted of 38 specimens that can be classified into four species. The examination of adult shell morphology of these original materials revealed that the current taxonomic account of S. multigranosa should be amended. Therefore, we designate a lectotype for S. multigranosa, and thus describe S. multigranosa auct. as Semisulcospira davisi sp. nov. Semisulcospira davisi can be discriminated from the other congeners by the characteristics of adult and embryonic shells, and radulae morphology. The present study resolves one of the fundamental taxonomic problems remaining in Semisulcospira snails.

Prognostic benefit of conversion surgery for HER2 positive stage IV gastric cancer; a case series study of eleven patients treated with trastuzumab-based chemotherapy.

BACKGROUND: Since the ToGA trial, trastuzumab-based chemotherapy is the standard treatment for HER2 positive stage IV gastric cancer. However, it is not yet clear whether surgical resection after trastuzumab-based chemotherapy (conversion surgery) can improve survival of HER2 positive stage IV gastric cancer. The purpose of this study is to evaluate the prognostic benefit of conversion surgery in HER2 positive stage IV gastric cancer patients. CASE PRESENTATION: We retrospectively investigated the medical records of the patients with HER2 positive (IHC3(+) or IHC2(+)/FISH(+)) stage IV gastric cancer treated with trastuzumab-based chemotherapy as the first line treatment. Overall survival (OS) was compared between patients with conversion surgery and without. Eleven HER2 positive stage IV gastric cancer patients treated with trastuzumab-based chemotherapy as the first line treatment were evaluated. Response rate was 63.6%, and 6 of 11 patients could receive conversion surgery. R0 resection was achieved in four patients. In Kaplan-Meier analysis, patients who received conversion surgery showed significantly better OS than those without surgery (3-year survival rate, 66.7% vs. 20%, P = 0.03). The median OS of patients who achieved R0 resection is 51.8 months. CONCLUSIONS: Conversion surgery might have a survival benefit for HER2 positive stage IV gastric cancer patients. If curative surgery is technically possible, conversion surgery could be a treatment option for HER2 positive stage IV gastric cancer.

[Recurrence-Free Survival after Repeated Resections for Metastatic Inguinal Tumor in Colorectal Mucinous Adenocarcinoma-A Case Report].

A 79-year-old male presented with right inguinal mass and right leg pain. Laparoscopic right hemicolectomy was performed for transverse colon cancer(type 1, muc, pSS, pN1a, pStage Ⅲa)3 years and 6 months ago. We resected the mass located in the spermatic cord and reconstructed it using the Direct Kugel Patch. Histopathological examination revealed mucinous carcinoma and was diagnosed as a metastatic lesion. Local recurrence was detected in the spermatic cord 1 year after resection, and radical inguinal orchiectomy was performed. Six months after the surgery performed for local recurrence, repeated recurrence was detected in the mesh used for reconstruction. Because this recurrence time was short, the patient opted for chemotherapy; however, this resulted in tumor growth, and surgery had to be scheduled. We performed extended resection of the abdominal wall and reconstruction using the fascia lata tensor muscle flap. Although intestinal obstruction, aspiration pneumonia, and skin flap necrosis were observed, the patient was discharged on the 85th postoperative day and remained alive without recurrence for 17 months. Mucinous carcinoma tends to cause local recurrence and requires adequate surgical margin resection. Extended excision should be considered in such cases of repeated local recurrence without distant metastases.

[Optimal Dissection of the Intestinal Tract and Preservation of Vascular Supply in Left Hemicolectomy Using Simulation Computed Tomography Colonography].

Left hemicolectomy is a standard surgical method for cancer of the descending colon. Resection involves the region from the left side of the transverse colon to the sigmoid colon. Although laparoscopic hemicolectomy is widely used, it is difficult to determine an appropriate resection range during surgery because of the limited visual field. Simulation computed tomography colonography(S-CTC), which combines CTC and 3-dimensional vascular imaging, enables the surgeon to clearly identify the position of the primary lesion and dominant vessel. We present 3 cases of cancer of the descending colon with different affected sites and lesion grades, in which appropriate dissection of the large intestine and treatment of the vessels was simulated by S-CTC, enabling laparoscopic surgery in accordance with the simulation. Case 1: Splenic flexure, cT1bN0M0, Stage I . The dominant vessels were identified by S-CTC as accompanying vessels branching from the accessary middle colic artery(A-MCA)and inferior mesenteric vein(IMV). The left branch of the MCA and the left colic artery(LCA)were 10 cm or more apart. A D2-type dissection was performed, and simulation was conducted for dissection of the branching root of the vein and the same level of the A-MCA. Case 2: Mid-descending colon, cT3N0M0, Stage II . The dominant A-MCA and LCA were identified with S-CTC. The intestinal tract was dissected to 5 cm from the dominant artery, and D3-type dissection was simulated with a retained inferior mesenteric artery(IMA)for preservation of the sigmoid colon. Case 3: Site adjacent to the sigmoid colon, cT3N0M0, Stage II . S-CTC identified the first sigmoid artery(S1)as the dominant artery, and revealed that the LCA and IMV were defective and that the A-MCA was 10 cm or more apart. Simulation of S1 selective resection was conducted such that D3-type dissection was performed, with a retained IMA for preservation of the sigmoid colon. In all 3 cases, laparoscopic surgeries were performed in accordance with the simulation. S-CTC was useful for optimal preservation of the intestinal tract and vascular supply in laparoscopic surgery for descending colon cancer.

[A Case of Pathologically Complete Response of a Rectal Cancer after Preoperative Treatment with mFOLFOX6 and Radiation Therapy].

A 60-year-old man who had bloody stools after sigmoid colonoscopy was admitted to our hospital. A digital examination and sigmoid colonoscopy showed a type 2 circular tumor at location Rb with incomplete mobility and tumor hemorrhage, and the result of a biopsy was moderately differentiated adenocarcinoma (tub2). Computed tomography and magnetic resonance imaging suggested a possibility of invasion of the primary rectal tumor to the sacrum. The clinical stage was cT4bN0M0H0P0, cStage Ⅱ, which is generally not treatable by surgery. Sigmoid colostomy was performed, and a central venous port was implanted. After a preoperative treatment consisting of 3 courses of mFOLFOX6 and radiation therapy, the clinical stage changed to ycT2N0M0H0P0, ycStageⅠ. Super-low anterior resection and covering ileostomy were performed 46 days after the preoperative treatment. A pathological examination revealed no residual cancer cells in the primary lesion and lymph node (Grade 3, pCR). The patient has been disease-free for 4 years and 9 months after the operation.