Microplastic contamination in east Antarctic sea ice.

The durability of plastics in the marine environment has led to concerns regarding the pervasiveness of this debris in remote polar habitats. Microplastic (MP) enrichment in East Antarctic sea ice was measured in one ice core sampled from coastal land-fast sea ice. The core was processed and filtered material was analyzed using micro Fourier-Transform Infrared (µFTIR) spectroscopy. 96 MP particles were identified, averaging 11.71 particles L-1. The most common MP polymers (polyethylene, polypropylene, and polyamide) were consistent with those most frequently represented in the majority of marine MP studies. Sea-ice MP concentrations were positively related with chlorophyll a, suggesting living biomass could assist in incorporating MPs in sea ice. Our preliminary results indicate that sea ice has the potential to serve as a reservoir for MP debris in the Southern Ocean, which may have consequences for Southern Ocean food webs and biogeochemistry.

Prognostic value of Ki67 in localized prostate carcinoma: a multi-institutional study of >1000 prostatectomies.

BACKGROUND: Expanding interest in and use of active surveillance for early state prostate cancer (PC) has increased need for prognostic biomarkers. Using a multi-institutional tissue microarray resource including over 1000 radical prostatectomy samples, we sought to correlate Ki67 expression captured by an automated image analysis system with clinicopathological features and validate its utility as a clinical grade test in predicting cancer-specific outcomes. METHODS: After immunostaining, the Ki67 proliferation index (PI) of tumor areas of each core (three cancer cores/case) was analyzed using a nuclear quantification algorithm (Aperio). We assessed whether Ki67 PI was associated with clinicopathological factors and recurrence-free survival (RFS) including biochemical recurrence, metastasis or PC death (7-year median follow-up). RESULTS: In 1004 PCs (∼4000 tissue cores) Ki67 PI showed significantly higher inter-tumor (0.68) than intra-tumor variation (0.39). Ki67 PI was associated with stage (P<0.0001), seminal vesicle invasion (SVI, P=0.02), extracapsular extension (ECE, P<0.0001) and Gleason score (GS, P<0.0001). Ki67 PI as a continuous variable significantly correlated with recurrence-free, overall and disease-specific survival by multivariable Cox proportional hazard model (hazards ratio (HR)=1.04-1.1, P=0.02-0.0008). High Ki67 score (defined as ⩾5%) was significantly associated with worse RFS (HR=1.47, P=0.0007) and worse overall survival (HR=2.03, P=0.03). CONCLUSIONS: In localized PC treated by radical prostatectomy, higher Ki67 PI assessed using a clinical grade automated algorithm is strongly associated with a higher GS, stage, SVI and ECE and greater probability of recurrence.

Regulation of insulin-like growth factor I (IGF-I) gene expression in brain of transgenic mice expressing an IGF-I-luciferase fusion gene.

Insulin-like growth factor I (IGF-I) plays an important role in the development and function of the central nervous system (CNS). Little is known, however, about the factors and mechanisms involved in regulation of CNS IGF-I gene expression. To facilitate our goal to define mechanisms of IGF-I gene regulation in the CNS, we generated several lines of transgenic (Tg) mice that express firefly luciferase (LUC) under control of a 11.3-kb fragment from the 5' region of the rat IGF-I gene. Consistent with expression of the native IGF-I gene in murine brain, expression of the transgene predominated in neurons and astrocytes and used promoter 1, the major IGF-I promoter in the CNS and in most tissues. Transgene messenger RNA and protein expression rapidly increased after birth and peaked at postnatal (P) day 4 in all brain regions studied. LUC activities in all regions then gradually decreased to 0.5-4% of their peak values at P31, except for the olfactory bulb, which maintained about one third of its maximal activity. Compared with littermate controls, administration of dexamethasone decreased LUC activity and transgenic IGF-I messenger RNA abundance, whereas GH significantly increased the expression of the transgene. Addition of GH to cultured fetal brain cells from Tg mice for 12 h also increased LUC activity in a dose-dependent manner (77-388%). These results show that this IGF-I promoter transgene is expressed in a fashion similar to the endogenous IGF-I gene, and thus indicates that the transgene contains cis-elements essential for developmental, GH, and glucocorticoid regulation of IGF-I gene expression in the CNS. These Tg mice should serve as an useful model to study mechanisms of IGF-I gene regulation in the brain.

A genetic linkage map of mouse chromosome 2 extending from thrombospondin to paired box gene 1, including the H3 minor histocompatibility complex.

The classical minor histocompatibility 3 (H3) locus was originally defined by the phenotype of skin graft rejection, which is a complex genetic trait. H3 is now known to be a gene complex comprised of a minimum of two functionally interdependent alloantigen-encoding loci, H3a and H3b. H3a encodes a peptide recognized by cytotoxic T cells, and H3b encodes a peptide that stimulates helper T cells. The H3 complex also contains the beta2-microglobulin gene (B2m), and polymorphisms in B2m contribute to the tissue rejection phenotype. We describe a high-density genetic linkage map of a 16-cM region of mouse Chromosome 2 from thrombospondin (Thbs1) to paired box gene 1 (Pax1). This genetic map includes H3a, H3b, and B2m. Other genes and anonymous loci have also been placed on the map. H3a maps between D2Mit444 and B2m in close vicinity to several known genes. H3b maps 12 cM distal to H3a, and the proprotein convertase subtilisin/kexin type 2 gene (Pcsk2; formerly Nec2) cosegregates with H3b in a high-resolution backcross panel. The H3 complex spans a region that shows conserved synteny to human chromosomes 15q, 2q, and 20p.

Accumulation of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents by double-crested cormorant (Phalacrocorax auritus, Pelicaniformes) chicks in the North American Great Lakes.

Concentrations of polychlorinated biphenyls (PCBs), and 2,3,7,8-tetrachlordibenzo-p-dioxin equivalents (TCDD-EQ) were determined in eggs and chicks of double-crested cormorants (DCC) which were collected in 1989 from eight locations in the Laurentian Great Lakes. The mean biomagnification factor (BMF) from forage fish to eggs was found to be 31.3. Absolute and relative concentrations as well as rates of accumulation of total concentrations of PCBs and TCDD-EQ were measurable in all of the samples. The concentrations of both PCBs and TCDD-EQs decreased immediately upon hatching of chicks, due to growth dilution. Initial decreases in absolute masses of TCDD-EQ in chicks were also observed, which indicates that there can be significant elimination of these compounds during early development. The initial rates of accumulation by chicks were dependent only on the mass of fish consumed. After the chicks began thermoregulating, the rates of accumulation, expressed as a concentration, normalized to body weight, became greater. Rates of accumulation of both PCBs and TCDD-EQ were correlated with their respective concentrations in forage fish consumed by the chicks. The relative potency, expressed as the ratio of the concentration of TCDD-EQ to that of total PCBs was calculated to determine if there was significant trophic-level enrichment of the TCDD-EQs, relative to total concentrations of PCBs. A significant enrichment was observed at the more and less contaminated locations, but the degree of enrichment was greater at the less contaminated locations (26 vs 72 micrograms/g).