Assessing amino acid racemization variability in coral intra-crystalline protein for geochronological applications.

Over 500 Free Amino Acid (FAA) and corresponding Total Hydrolysed Amino Acid (THAA) analyses were completed from eight independently-dated, multi-century coral cores of massive Porites sp. colonies. This dataset allows us to re-evaluate the application of amino acid racemization (AAR) for dating late Holocene coral material, 20 years after Goodfriend et al. (GCA56 (1992), 3847) first showed AAR had promise for developing chronologies in coral cores. This re-assessment incorporates recent method improvements, including measurement by RP-HPLC, new quality control approaches (e.g. sampling and sub-sampling protocols, statistically-based data screening criteria), and cleaning steps to isolate the intra-crystalline skeletal protein. We show that the removal of the extra-crystalline contaminants and matrix protein is the most critical step for reproducible results and recommend a protocol of bleaching samples in NaOCl for 48 h to maximise removal of open system proteins while minimising the induced racemization. We demonstrate that AAR follows closed system behaviour in the intra-crystalline fraction of the coral skeletal proteins. Our study is the first to assess the natural variability in intra-crystalline AAR between colonies, and we use coral cores taken from the Great Barrier Reef, Australia, and Jarvis Island in the equatorial Pacific to explore variability associated with different environmental conditions and thermal histories. Chronologies were developed from THAA Asx D/L, Ala D/L, Glx D/L and FAA Asx D/L for each core and least squares Monte Carlo modelling applied in order to quantify uncertainty of AAR age determinations and assess the level of dating resolution possible over the last 5 centuries. AAR within colonies follow consistent stratigraphic aging. However, there are systematic differences in rates between the colonies, which would preclude direct comparison from one colony to another for accurate age estimation. When AAR age models are developed from a combined dataset to include this natural inter-colony variability THAA Asx D/L, Glx D/L and Ala D/L give a 2σ age uncertainty of ±19, ±38 and ±29 year, for the 20th C respectively; in comparison 2σ age uncertainties from a single colony are ±12, ±12 and ±14 year. This is the first demonstration of FAA D/L for dating coral and following strict protocols 2σ precisions of ±24 years can be achieved across different colonies in samples from the last 150 years, and can be ±10 years within a core from a single colony. Despite these relatively large error estimates, AAR would be a valuable tool in situations where a large number of samples need to be screened rapidly and cheaply (e.g. identifying material from mixed populations in beach or uplift deposits), prior to and complementing the more time-consuming geochronological tools of U/Th or seasonal isotopic timeseries

An EORTC pilot study of filgrastim (recombinant human granulocyte colony stimulating factor) as support to a high dose-intensive epiadriamycin-cyclophosphamide regimen in chemotherapy-naive patients with locally advanced or metastatic breast cancer.

BACKGROUND: In an attempt to increase chemotherapy dose intensity by step-wise reduction of the time interval between treatment cycles, filgrastim was administered to breast cancer patients receiving a three-month combination chemotherapy with epirubicin (E) and cyclophosphamide (C). PATIENTS AND METHODS: Chemotherapy-naïve patients with locally advanced or metastatic breast cancer received fixed doses of E (120 mg/m2) and C 9830 mg/m2) by 15-min i.v. infusion on day 1 of each cycle and filgrastim at a dose of 4 micrograms/kg once daily by SC injection starting 24 hours after chemotherapy. Cohorts of patients were treated in successive schedules, each schedule corresponding to a specified time interval between chemotherapy cycles. The toxicity observed in each schedule was evaluated before patients were accrued to the next schedule, which corresponded to a shorter time interval between chemotherapy cycles. RESULTS: The maximum tolerated schedule was E (120 mg/m2) plus C 9830 mg/m2) given every 14 days with filgrastim support from day 2 until day 13. On this schedule, 5 of 12 patients experienced dose-intensity-limiting toxicities (DLT) during the 3-month study period. Non-hematological DLT occurred in 2/12 patients (mucositis, skin toxicity) while /312 experienced febrile neutropenia requiring i.v. antibiotics. All patients achieved recovery of ANC to >1.5 x 10(9)/l by the time of scheduled retreatment. The combination of filgrastim with this regimen did not seem to add major toxicities. The efficacy was high, with 87% of patients achieving an objective response and a median response duration of 18 months (range: 4-52 months). CONCLUSIONS: Filgrastim permits at 33% increase in 'EC' dose intensification over that of the conventional every-3-week administration. Randomized studies should now be initiated to evaluate the merit, if any, of 'accelerated' chemotherapy in advanced breast cancer.Clinical TrialJournal ArticleMulticenter StudyResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Atlas der Alpenflora / Meergrauer Steinbrech

Magasság: 1300-2700 M.Előfordulási hely: Schweiz bis Oesterr. u. Steierm., trockene StellenVirágzás: Juni, Jul

Disruption of the ASTN2/TRIM32 locus at 9q33.1 is a risk factor in males for autism spectrum disorders, ADHD and other neurodevelopmental phenotypes

Rare copy number variants (CNVs) disrupting ASTN2 or both ASTN2 and TRIM32 have been reported at 9q33.1 by genome-wide studies in a few individuals with neurodevelopmental disorders (NDDs). The vertebrate-specific astrotactins, ASTN2 and its paralog ASTN1, have key roles in glial-guided neuronal migration during brain development. To determine the prevalence of astrotactin mutations and delineate their associated phenotypic spectrum, we screened ASTN2/TRIM32 and ASTN1 (1q25.2) for exonic CNVs in clinical microarray data from 89 985 individuals across 10 sites, including 64 114 NDD subjects. In this clinical dataset, we identified 46 deletions and 12 duplications affecting ASTN2. Deletions of ASTN1 were much rarer. Deletions near the 3' terminus of ASTN2, which would disrupt all transcript isoforms (a subset of these deletions also included TRIM32), were significantly enriched in the NDD subjects (P = 0.002) compared with 44 085 population-based controls. Frequent phenotypes observed in individuals with such deletions include autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), speech delay, anxiety and obsessive compulsive disorder (OCD). The 3'-terminal ASTN2 deletions were significantly enriched compared with controls in males with NDDs, but not in females. Upon quantifying ASTN2 human brain RNA, we observed shorter isoforms expressed from an alternative transcription start site of recent evolutionary origin near the 3' end. Spatiotemporal expression profiling in the human brain revealed consistently high ASTN1 expression while ASTN2 expression peaked in the early embryonic neocortex and postnatal cerebellar cortex. Our findings shed new light on the role of the astrotactins in psychopathology and their interplay in human neurodevelopment