An experimental evaluation of transgenerational isotope labelling in a coral reef grouper

Transgenerational isotope labelling (TRAIL) using enriched stable isotopes provides a novel means of mass-marking marine fish larvae and estimating larval dispersal. The technique, therefore, provides a new way of addressing questions about demographic population connectivity and larval export from no-take marine protected areas. However, successful field applications must be preceded by larval rearing studies that validate the geochemical marking technique, determine appropriate concentrations and demonstrate that larvae are not adversely affected. Here, we test whether injection of enriched stable barium isotopes (135Ba and 137Ba) at two dose rates produces unequivocal marks on the otoliths of the coral reef grouper Epinephelus fuscoguttatus. We also assess potential negative effects on reproductive performance, egg size, condition and larval growth due to injection of adult female fish. The injection of barium isotopes at both 0.5 and 2.0 mg Ba/kg body weight into the body cavities of gravid female Wsh was 100% successful in the geochemical tagging of the otoliths of larvae from the first spawning after injection. The low-dose rate produced no negative effects on eggs or larvae. However, the higher dose rate of 2 mg Ba/kg produced small reductions in yolk sac area, oil globule area, standard length and head depth of pre-feeding larvae. Given the success of the 0.5 mg Ba/kg dose rate, it is clearly possible to produce a reliable mark and keep the concentration below any level that could affect larval growth or survival. Hence, enriched Ba isotope injections will provide an effective means of mass-marking grouper larvae

Comparison of multiphase CT, FDG-PET and intra-operative ultrasound in patients with colorectal liver metastases selected for surgery.

Contains fulltext : 52091.pdf (publisher's version ) (Closed access)BACKGROUND: For patients with colorectal liver metastases, resection is the treatment of choice. Careful selection of these patients is crucial in order to reduce the chance of unexpected findings at laparotomy and abandoning further surgical intervention. Here, we evaluate the predictive value of CT and FDG-PET of the liver and extrahepatic findings compared to findings during laparotomy and 6 months follow-up. METHODS: 131 consecutive patients, selected for hepatic surgery for colorectal liver metastases by CT and FDG-PET, were evaluated prospectively. During surgery, the liver was assessed by intra-operative ultrasound, palpation and histology. RESULTS: In 127 patients (97%), CT was true-positive for liver metastases. In 3 patients, CT was false-positive and in 1 patient false-negative. In 126 patients (96%), FDG-PET was true-positive for liver metastases, in 2 patients FDG-PET was false-negative, in 3 patients true-negative (negative FDG-PET, false-positive CT). At laparotomy a total of 363 liver metastases was identified: 63 lesions 20 mm [124 (97%) CT-positive, 121 (95%) FDG-PET-positive]. CT and FDG-PET missed approximately 30% of the smaller liver lesions, resulting in a significant change in clinical management during surgery in only nine patients. CONCLUSIONS: CT and FDG-PET have a similar diagnostic yield for the identification of liver metastases; both modalities being adequate on a patient-basis but inadequate to detect the smallest of liver lesions. However, the clinical relevance of the latter is limited