The competitive advantage of Microcystis aeruginosa over Scenedesmus obliquus weakened by exposure to polylactic acid microplastics.

Aquatic ecosystems are heavily affected by microplastics (MPs), and its impacts on aquatic life have received extensive attention. However, it is still unclear how biodegradable MPs influence the growth and competition of phytoplankton. In this study, the response of growth dynamics, alternation in algal cell morphology and toxin-producing capability, and changes in the extracellular process of Microcystis aeruginosa (M. aeruginosa) and Scenedesmus obliquus (S. obliquus) were systematically studied in monoculture and co-culture conditions with and without the presence of polylactic acid MPs (PLA-MPs). The results indicated that although the loss of cell integrity was observed, PLA-MPs addition (50 mg/L) caused a 1.40- and 1.36-fold increase in cell densities of M. aeruginosa and S. obliquus in monoculture systems, respectively. This suggests the PLA-MPs more favored the growth of M. aeruginosa. This effect was manifested in co-culture conditions, because the degradation of PLA-MPs provided additional inorganic carbon in the experimental systems and benefited the growth of both M. aeruginosa and S. obliquus. Meanwhile, the synthesis of microcystins from the toxic M. aeruginosa was substantially reduced upon PLA-MPs exposure, which reduced the competitive advantage of M. aeruginosa over S. obliquus. Thus; the cell density of M. aeruginosa and S. obliquus showed 1.15- and 1.88-folds increasing compared to that without PLA-MPs addition. This interaction between PLA-MPs and algae weakened the competitive advantage of M. aeruginosa over S. obliquus, but their competitive outcomes remained unchanged. The results provided new insights into understanding the potential ecological risks of biodegradable plastics in aquatic ecosystems.

Major hepatectomy for primary hepatolithiasis: a comparative study of laparoscopic versus open treatment.

BACKGROUND: Due to higher technical requirements, laparoscopic major hepatectomy (LMH) for primary hepatolithiasis have been limited to a few institutions. This retrospective study was performed to evaluate the therapeutic safety, and perioperative and long-term outcomes of LMH versus open major hepatectomy (OMH) for hepatolithiasis. METHODS: From January 2012 to December 2016, 61 patients with hepatolithiasis who underwent major hepatectomy were enrolled, including 29 LMH and 32 OMH. The perioperative outcomes and postoperative complications, as well as long-term outcomes, including the stone clearance and recurrence rate, were evaluated. RESULTS: There was no difference of surgical procedures between the two groups. The mean operation time was (262 ± 83) min in the LMH group and (214 ± 66) min in the OMH group (p = 0.05). There is no difference of intra-operative bleeding (310 ± 233) ml versus (421 ± 359) ml (p = 0.05). In the LMH group, there were shorter time to postoperative oral intake ((1.1 ± 0.6) days versus (3.1 ± 1.8) days, p = 0.01) and shorter hospital stay [(7.2 ± 2.3) days versus (11.8 ± 5.5) days, p = 0.03] than the open group. The LMH group had comparable stone clearance rate with the OMH group during the initial surgery (82.8% vs. 84.4%, p = 0.86). CONCLUSIONS: LMH could be an effective and safe treatment for selected patients with hepatolithiasis, with an advantage over OMH in the field of less intra-operative blood loss, less intra-operative transfusion, less overall complications, and faster postoperative recovery.

Laparoscopic Anatomical Segment VII Resection for Hepatocellular Carcinoma Using the Glissonian Approach with Indocyanine Green Dye Fluorescence.

BACKGROUND: Many studies confirm that anatomical resection was associated with favorable oncologic outcomes for patients with HCC who had preserved as much of the remnant liver tissue as possible.1,2 In recent years, laparoscopic liver resection has been widely extended from minor resection to complex hepatectomy,3 However, surgery on tumors located in the posterosuperior segment remains a demanding procedure regardless of the extent of resection.4 Laparoscopic anatomical segment VII resection has one of the highest difficulty scores based on the tumor location due to poor accessibility, hard to exposure, and difficulty in obtaining sufficient surgical margins.5,6 Here, we report a totally laparoscopic anatomical VII resection using the Glissonian approach with indocyanine green dye fluorescence. METHODS: A 74-year-old man with a body mass index of 31.9 kg/m2 suffered from HBV-related cirrhosis was admitted to our institution. The preoperative Gd-EOB-DTPA MRI showed a 2.7-cm HCC located in segment VIII. The preoperative AFP is 3431 ng/ml. A true anatomical segmentectomy was performed by using selective occlusion of segment VII Glissonian pedicle, which was identified from the liver hilum. Indocyanine green (ICG) dye demarcation was used as a guidance during parenchymal transection. RESULTS: The operative time was 270 min with an estimated blood loss of 200 mL. The postoperative course was uneventful. Drainage tube was pulled out on the fourth day. The pathology confirmed the diagnosis of hepatocellular carcinoma and the surgical margin was negative. The patient was discharged on the 8th day after operation. CONCLUSIONS: Totally laparoscopic anatomical segment VII resection is a technically challenging operation. Advanced laparoscopic skills are necessary to complete such a difficult procedure safely. Glissonian approach and ICG fluorescence imaging guide parenchyma resection could be help.