Efficient pH and dissolved CO2 conditions for indoor and outdoor cultures of green alga Parachlorella.

Efficient pH and dissolved CO2 conditions for indoor (50-450 mL scale) and outdoor (100-500 L scale) culture of a green alga BX1.5 strain that can produce useful intracellular lipids and extracellular polysaccharides were investigated for the first time in Parachlorella sp. The cultures harvested under 26 different conditions were analysed for pH, dissolved CO2 concentration, and the biomass of extracellular polysaccharides. The BX1.5 strain could thrive in a wide range of initial medium pH ranging from 3 to 11 and produced valuable lipids such as C16:0, C18:2, and C18:3 under indoor and outdoor culture conditions when supplied with 2.0% dissolved CO2. Particularly, the acidic BG11 medium effectively increased the biomass of extracellular polysaccharides during short-term outdoor cultivation. The BG11 liquid medium also led to extracellular polysaccharide production, independent of acidity and alkalinity, proportional to the increase in total sugars derived from cells supplied with high CO2 concentrations. These results suggest Parachlorella as a promising strain for indoor and outdoor cultivation to produce valuable materials.

Lymph node metastasis can be determined by just tumor depth and lymphovascular invasion in early gastric cancer patients after endoscopic submucosal dissection.

PURPOSE: Endoscopic submucosal dissection (ESD) is a minimally invasive treatment for early gastric cancer (EGC) with negligible risk of lymph node metastasis (LNM). When a patient is determined to have noncurative resection after ESD, additional surgical resection with lymph node dissection is recommended. Previous studies report that LNM is found in about 10% of these patients. It may be possible to avoid unnecessary surgical resection by selecting patients properly. We aimed to clarify the risk factors associated with LNM in EGC patients who underwent ESD and to develop a highly accurate diagnostic algorithm for LNM. PATIENTS AND METHODS: Among 1005 patients with EGC who underwent ESD, 423 patients who could be followed up for more than 3 years after treatment or who underwent additional surgical resection were examined. We used the leave-one-out method to explore the combination of predictive factors of LNM and differentiated LNM by a unique classifier. RESULTS: Curative resection was achieved in 322 patients, whereas noncurative resection was achieved in 101 patients. In the noncurative resection group, LNM occurred in eight patients with additional surgical resection and one patient during follow-up. The combination of depth of invasion, lymphatic, and venous invasion showed the highest diagnostic performance and could differentiate LNM with 100% sensitivity, 86% specificity, and 86% diagnostic accuracy. CONCLUSION: More than 500 µm submucosal invasion and lymphatic and venous invasion will be useful in assessing LNM after ESD for patients with EGC. When these three factors are not observed, follow-up alone might be appropriate and it may be possible to reduce unnecessary surgical resection.

Evaluation of the Diagnostic Ability of Optical Enhancement System in Early Gastric Cancer Demarcation.

This study aimed to evaluate the utility of optical enhancement (OE) in early gastric cancer demarcation. Twenty lesions of early gastric cancer were examined by PENTAX endoscopy system with OE-1 and OE-2 functions. The areas of tumor demarcation identified by 12 evaluators (6 novice and 6 experienced) were compared to the corresponding correct areas determined by postoperative histopathology findings. The misdiagnosed scores that were the sums of false-positive and false-negative areas were compared. Color of one hundred pixels from the inside of the cancerous area and the outside of the cancerous area was expressed as three-dimensional RGB component vectors. The mean vectors and covariance matrixes were calculated and the Mahalanobis distance, indicative of color differences between two areas, was tested. Comparisons of the misdiagnosed score revealed that OE-1 was preferred over WL-1 for gastric cancer demarcation for all 12 evaluators (p = 0.008) and in novice evaluators (p = 0.026). OE-2 was not significantly different from WL-2 in all cases. OE-1 images gave significantly larger Mahalanobis distances, indicative of color differences, than WL-1 images (p = 0.002). It was demonstrated that the OE Mode 1 has a significant advantage over the white light mode in demarcation of early gastric cancer.

Preliminary study of photodynamic diagnosis using 5-aminolevulinic acid in gastric and colorectal tumors.

AIM: To investigate the utility of photodynamic diagnosis (PDD) using 5-aminolevulinic acid (5-ALA) to detect gastric/colorectal tumors. METHODS: This prospective single-center study investigated inter-subject variability in patients with early-stage gastric/colorectal tumor indicated for endoscopic resection. Subjects were patients with gastric or colorectal tumors who had undergone endoscopic resection between November 2012 and November 2013. Selection criteria included age 20-80 years, either sex, and provision of informed consent. Patients were orally administered 20 mg/kg of 5-ALA enteric-coated capsules (SBI ALApromo Co., Tokyo, Japan). Administration of 5-ALA was followed by endoscopic resection of gastric or colorectal tumors, and the resected specimens were examined using a video autofluorescence processor and a fluorescence endoscope (SAFE-3000 and EB-1970AK, respectively; Pentax, Tokyo, Japan). The primary endpoint was the presence of fluorescence in tumors. Endoscopic, macroscopic, and histopathologic findings of tumors were assessed. We also evaluated adverse events of the present procedure as a secondary endpoint and examined each patient for the presence of known adverse effects of 5-ALA, namely, hematocytopenia, liver dysfunction, hypotension, nausea, and photosensitivity. RESULTS: We enrolled 10 patients (7 men, 3 women) (n = 13 lesions: 10 gastric/3 colorectal tumors). Fluorescence was detected in 7/13 (53.8%) lesions. No significant differences in sex (male: 55.6% vs female: 50.5%, P = 1.00), age (67.1 ± 1.9 years vs 65.0 ± 2.0 years, P = 0.45), tumor color (reddish: 60.0% vs discolored: 33.3%, P = 0.56), tumor diameter (15.0 ± 2.1 mm vs 14.2 ± 2.3 mm, P = 0.80), macroscopic type (protruded: 70.0% vs depressed 0%, P = 0.07), histologic type (differentiated type: 58.3% vs 0%, P = 0.46), invasion depth (mucosal layer: 55.6% vs submucosal layer: 33.3%, P = 1.00), lymphatic invasion (present: 33.3% vs absent: 50.0%, P = 1.00), venous invasion (present: 0% vs absent: 54.5%, P = 1.00) or procedure time of endoscopic resection (36.3 ± 8.3 min vs 36.7 ± 9.0 min, P = 0.98) were observed between the patients with and without fluorescence. Fluorescence detection rate tended to be high for elevated lesions. Liver dysfunction developed in 4/10 (40.0%) patients. The extent of the liver dysfunction was a slight increase in transaminases and total bilirubin levels, which spontaneously improved in the patients. None of the patients developed photosensitivity. CONCLUSION: Results of this preliminary study suggest the utility of PDD using 5-ALA for screening of gastric and colorectal cancers.