Cryopreservation of Pyramimonas mucifera.

BACKGROUND: It is important to appreciate microalgal diversity, better understand their ecosystem functioning and therefore implement conservation measures. The National Biodiversity Act of South Africa has a marine and coastal component which promotes such investigations. OBJECTIVE: To develop a cryostorage method for the marine unicellular algal species Pyramimonas mucifera. MATERIALS AND METHODS: Cell viability, measured by propidium iodide, was used to determine both optimal exposure time to 10 % DMSO and survival following thawing of cryopreserved cells. Cryopreservation was achieved by a two-step cooling method. RESULTS AND DISCUSSION: A 30-min DMSO exposure was selected for P. mucifera, as cells following such treatment retained cell shape and integrity. Although density was significantly reduced after cryopreservation, the surviving cells were capable of returning to viability levels equal to those of the untreated control (> 90%). CONCLUSION: Cultures of P. mucifera can be successfully cryopreserved and propidium iodide provides a useful indication of culture vitality.

Metastasectomy for recurrent or metastatic biliary tract cancers: A single center experience.

PURPOSE: To assess efficacy or long-term result of metastasectomy for recurrent or metastatic biliary tract carcinoma (BTC), we conducted a retrospective review of the outcomes of metastasectomy for recurrent or metastatic BTCs, comprising intrahepatic cholangiocellular carcinoma (IHCCC), proximal and distal common bile duct cancer (pCBDC and dCBDC), gallbladder cancer (GBC), and ampulla of Vater cancer (AoVC). PATIENTS AND METHODS: The clinicopathological features and outcomes of BTC patients who underwent surgical resection for the primary and metastatic disease at the Gachon University Gil Medical Centre from 2003 to 2013 were reviewed retrospectively. RESULTS: We found 19 eligible patients. Primary sites were GBC (seven patients, 37%), IHCCC (five patients, 26%), dCBDC (three patients, 16%), pCBDC (two patients, 11%), and AoVC (two patients, 11%). Eight patients (42%) had synchronous metastasis whereas 11 (58%) had metachronous metastasis. The most common metastatic site was liver (nine patients, 47%), lymph node (nine patients, 47%), and peritoneum (three patients, 16%). Nine patients (47%) achieved R0 resection, whereas four (21%) and six (32%) patients had R1 and R2 resection, respectively. With a median follow-up period of 26.7 months, the estimated median overall survival (OS) was 18.2 months (95% confidence interval, 13.6-22.9 months). Lower Eastern Cooperative Oncology Group performance status (P = 0.023), metachronous metastasis (P = 0.04), absence of lymph node metastasis (P = 0.009), lower numbers of metastatic organs (P < 0.001), normal postoperative CA19-9 level (P = 0.034), and time from diagnosis to metastasectomy more than 1 year (P = 0.019) were identified as prognostic factors for a longer OS after metastasectomy. CONCLUSIONS: For recurrent or metastatic BTCs, metastasectomy can be a viable option for selected patients.

Phosphorus limitation and starvation effects on cell growth and lipid accumulation in Isochrysis galbana U4 for biodiesel production.

The effect of varying levels of phosphorus (P) on Isochrysis galbana U4 growth, pigmentation and lipid accumulation were investigated. A reduction in the P content to 25% of the recommended level for f/2 medium did not lead to declines in cell growth rates or lipid accumulation levels relative to the cultures maintained on medium supplemented with the normal P dose. Evidence suggesting that the recommended P supply in f/2 exceeds the requirements for maximal algal growth has obvious economic implications for the mass production of I. galbana for biodiesel production. When P supply was in excess this species was also found to accumulate intracellular levels of P that exceeded by up to 6 times its P requirements for growth and cell division. The reduction in P concentration to levels below 25% resulted in P starvation stimulated chlorophyll reductions and carotenoid and lipid accumulation in this species.