1,143 research outputs found
The potential for using acoustic tracking to monitor the movement of the West Coast rock lobster Jasus lalandii
Although acoustic tracking has been used to study the movement of several species of clawed and spiny lobsters, only recent technological advances have provided sufficiently small transmitters to examine the utility of using acoustic tracking as a means to analyse the movement of relatively small spiny lobsters, such as Jasus lalandii. The effect of the transmitter on the mobility of J. lalandii was tested in aquarium experiments and was shown to have no influence on movement in three separate experiments. Thereafter, adult male rock lobsters (86ā98mm carapace length) were tracked in field trials for up to 32 days at Betty's Bay (n = 4) and Hermanus (n = 5) off the Western Cape, South Africa. Tracking J. lalandii in the field using acoustic tags was successful, even in areas with dense kelp beds and rocky outcrops. The signal from the transmitters was readily detectable from the surface and subsequent use of underwater tracking equipment enabled visual confirmation of the position of the rock lobsters. Lobsters moved significantly longer distances (>45m dayā1) in the first two days following tagging than during any subsequent time period (<10m dayā1). This suggests that transmitter attachment and/or handling altered the movement pattern for the first 72 hours after tagging. During the period of observation, J. lalandii displayed classical nomadic behaviour
Phosphatidylinositol Transfer Protein-Ī± in platelets is inconsequential for thrombosis yet is utilized for tumor metastasis
Platelets are increasingly recognized for their contributions to tumor metastasis. Here, we show that the phosphoinositide signaling modulated by phosphatidylinositol transfer protein type Ī± (PITPĪ±), a protein which shuttles phosphatidylinositol between organelles, is essential for platelet-mediated tumor metastasis. PITPĪ±-deficient platelets have reduced intracellular pools of phosphoinositides and an 80% reduction in IP3 generation upon platelet activation. Unexpectedly, mice lacking platelet PITPĪ± form thrombi normally at sites of intravascular injuries. However, following intravenous injection of tumor cells, mice lacking PITPĪ± develop fewer lung metastases due to a reduction of fibrin formation surrounding the tumor cells, rendering the metastases susceptible to mucosal immunity. These findings demonstrate that platelet PITPĪ±-mediated phosphoinositide signaling is inconsequential for in vivo hemostasis, yet is critical for in vivo dissemination. Moreover, this demonstrates that signaling pathways within platelets may be segregated into pathways that are essential for thrombosis formation and pathways that are important for non-hemostatic functions
Recommended from our members
Converging Prefronto-Insula-Amygdala Pathways in Negative Emotion Regulation in Marmoset Monkeys
BACKGROUND: Impaired regulation of emotional responses to potential threat is a core feature of affective disorders. However, while the subcortical circuitry responsible for processing and expression of fear has been well characterized, the top-down control of this circuitry is less well understood. Our recent studies demonstrated that heightened emotionality, as measured both physiologically and behaviorally, during conditioned fear and innate/ social threat was induced, independently, by excitotoxic lesions of either the anterior orbitofrontal cortex (antOFC) or ventrolateral prefrontal cortex (vlPFC). An important outstanding question is whether the antOFC and vlPFC act on common or distinct downstream targets to regulate negative emotion.
METHODS: The question was addressed by combining localized excitotoxic lesions in the PFC of a nonhuman primate and functional neuroimaging ([F]fluorodeoxyglucose positron emission tomography) with a fear-regulating extinction paradigm. Marmoset monkeys with unilateral lesions of either the antOFC or vlPFC were scanned immediately following exposure to a fearful or safe context, and differences in [F]fluorodeoxyglucose uptake were evaluated.
RESULTS: [F]fluorodeoxyglucose uptake in the insula and amygdala of the intact hemisphere was significantly increased in response to the fearful context compared with the safe context. Such discrimination between the two contexts was not reflected in the activity of the insula-amygdala of the antOFC or vlPFC-lesioned hemisphere. Instead, uptake was at an intermediate level in both contexts.
CONCLUSIONS: These findings demonstrate that the distinct control functions of the antOFC and vlPFC converge on the same downstream targets to promote emotion regulation, taking us closer to a mechanistic understanding of different forms of anxiety.This research was supported by a Medical Research Programme Grant (No. MR/M023990/1) from the Medical Research Council (to ACR) and was carried out within the Behavioural and Clinical Neuroscience Institute supported by a consortium award from the Wellcome Trust and the Medical Research Council
Individual phosphatidylinositol transfer proteins have distinct functions that do not involve lipid transfer activity
Platelets utilize signal transduction pathways facilitated by Class I phosphatidylinositol transfer proteins (PITPs). The two mammalian Class I PITPs, PITPĪ± and PITPĪ², are single PITP domain soluble proteins that are encoded by different genes and have 77% sequence identity, though their individual roles in mammalian biology remain uncharacterized. These proteins are believed to shuttle phosphatidylinositol and phosphatidylcholine between separate intracellular membrane compartments, thereby regulating phosphoinositide synthesis and second messenger formation. Previously, we observed that platelet-specific deletion of PITPĪ±, the predominant expressed murine PITP isoform, had no effect on hemostasis, but had impaired tumor metastasis formation and disrupted phosphoinositide signaling. Here, we find that mice lacking the lesser expressed PITPĪ² in their platelets exhibit a similar phenotype. However, in contrast to PITPĪ±-null platelet lysates that have impaired lipid transfer activity, PITPĪ²-null platelet lysates have essentially normal lipid transfer activity, although both isoforms contribute to phosphoinositide synthesis in vitro. Moreover, we found that platelet-specific deletion of both PITPs leads to ex vivo platelet aggregation/secretion and spreading defects, impaired tail bleeding, and profound tumor dissemination. Our studies also demonstrate that PITP isoforms are required for maintaining endogenous phosphoinositide PI(4,5)P2 levels and agonist stimulated second messenger formation. The data shown here demonstrate that both class I PITP isoforms contribute to phosphoinositide signaling in platelets, likely through distinct biochemical mechanisms or in different subcellular domains. They are functionally overlapping and either single isoform is able to maintain the homeostasis of platelets
Dynamics in the satellite system of Triangulum: Is AndXXII a dwarf satellite of M33?
We present results from a spectroscopic survey of the dwarf spheroidal And
XXII and the two extended clusters EC1 and EC2. These three objects are
candidate satellites of the Triangulum galaxy, M33, which itself is likely a
satellite of M31. We use the DEep Imaging Multi-Object Spectrograph mounted on
the Keck-II telescope to derive radial velocities for candidate member stars of
these objects and thereby identify the stars that are most likely actual
members. Eleven most probable stellar members (of 13 candidates) are found for
AndXXII. We obtain an upper limit of sigma_v < 6.0 km s-1 for the velocity
dispersion of AndXXII, [Fe/H] ~ -1.6 for its metallicity, and 255pc for the
Plummer radius of its projected density profile. We construct a colour
magnitude diagram for AndXXII and identify both the red giant branch and the
horizontal branch. The position of the latter is used to derive a heliocentric
distance to And XXII of 853 pm 26 kpc. The combination of the radial velocity,
distance, and angular position of AndXXII indicates that it is a strong
candidate for being the first known satellite of M33 and one of the very few
examples of a galactic satellite of a satellite. N-body simulations imply that
this conclusion is unchanged even if M31 and M33 had a strong encounter in the
past few Gyr. We test the hypothesis that the extended clusters highlight
tidally stripped galaxies by searching for an excess cloud of halo-like stars
in their vicinity. We find such a cloud for the case of EC1 but not EC2. The
three objects imply a dynamical mass for M33 that is consistent with previous
estimates.Comment: 14 pages, 14 figures, revised for MNRAS publicatio
The Importance of Context and Cognitive Agency in Developing Police Knowledge: Going Beyond the Police Science Discourse
This paper argues the current exposition of police knowledge through the discourses of police science and evidenced based policing (EBP) leads to exaggerated claims about what is, and can be, known in policing. This new orthodoxy underestimates the challenges of applying knowledge within culturally-mediated police practice. The paper draws upon virtue epistemology highlighting the role cognitive agency plays in establishing knowledge claims. We challenge the assumption that it is possible to derive what works in all instances of certain aspects of policing and suggest it would be more apt to speak about what worked within a specific police context
Prospective longitudinal evaluation of treatment-related toxicity and health-related quality of life during the first year of treatment for pediatric acute lymphoblastic leukemia
Background: Pediatric acute lymphoblastic leukemia (ALL) therapy is accompanied by treatment-related toxicities (TRTs) and impaired quality of life. In Australia and New Zealand, children with ALL are treated with either Childrenās Oncology Group (COG) or international Berlin-Frankfurt-Munster (iBFM) Study Group-based therapy. We conducted a prospective registry study to document symptomatic TRTs (venous thrombosis, neurotoxicity, pancreatitis and bone toxicity), compare TRT outcomes to retrospective TRT data, and measure the impact of TRTs on childrenās general and cancer-related health-related quality of life (HRQoL) and parentsā emotional well-being. Methods: Parents of children with newly diagnosed ALL were invited to participate in the ASSET (Acute Lymphoblastic Leukaemia Subtypes and Side Effects from Treatment) study and a prospective, longitudinal HRQoL study. TRTs were reported prospectively and families completed questionnaires for general (Healthy Utility Index Mark 3) and cancer specific (Pediatric Quality of Life Inventory (PedsQL)-Cancer Module) health related quality of life as well the Emotion Thermometer to assess emotional well-being. Results: Beginning in 2016, 260 pediatric patients with ALL were enrolled on the TRT registry with a median age at diagnosis of 59 months (range 1ā213 months), 144 males (55.4%), majority with Pre-B cell immunophenotype, n = 226 (86.9%), 173 patients (66.5%) treated according to COG platform with relatively equal distribution across risk classification sub-groups. From 2018, 79 families participated in the HRQoL study through the first year of treatment. There were 74 TRT recorded, reflecting a 28.5% risk of developing a TRT. Individual TRT incidence was consistent with previous studies, being 7.7% for symptomatic VTE, 11.9% neurotoxicity, 5.4% bone toxicity and 5.0% pancreatitis. Childrenās HRQoL was significantly lower than population norms throughout the first year of treatment. An improvement in general HRQoL, measured by the HUI3, contrasted with the lack of improvement in cancer-related HRQoL measured by the PedsQL Cancer Module over the first 12 months. There were no persisting differences in the HRQoL impact of COG compared to iBFM therapy. Conclusions: It is feasible to prospectively monitor TRT incidence and longitudinal HRQoL impacts during ALL therapy. Early phases of ALL therapy, regardless of treatment platform, result in prolonged reductions in cancer-related HRQoL
52-week efficacy and safety of telbivudine with conditional tenofovir intensification at week 24 in HBeAg-positive chronic Hepatitis B
Background and Aims: The Roadmap concept is a therapeutic framework in chronic hepatitis B for the intensification of nucleoside analogue monotherapy based on early virologic response. The efficacy and safety of this approach applied to telbivudine treatment has not been investigated.
Methods: A multinational, phase IV, single-arm open-label study (ClinicalTrials.gov ID NCT00651209) was undertaken in HBeAg-positive, nucleoside-naive adult patients with chronic hepatitis B. Patients received telbivudine (600 mg once-daily) for 24 weeks, after which those with undetectable serum HBV DNA (<300 copies/mL) continued to receive telbivudine alone while those with detectable DNA received telbivudine plus tenofovir (300 mg once-daily). Outcomes were assessed at Week 52.
Results: 105 patients commenced telbivudine monotherapy, of whom 100 were included in the efficacy analysis. Fifty-five (55%) had undetectable HBV DNA at Week 24 and continued telbivudine monotherapy; 45 (45%) received tenofovir intensification. At Week 52, the overall proportion of undetectable HBV DNA was 93% (93/100) by last-observation-carried-forward analysis (100% monotherapy group, 84% intensification group) and no virologic breakthroughs had occurred. ALT normalization occurred in 77% (87% monotherapy, 64% intensification), HBeAg clearance in 43% (65% monotherapy, 16% intensification), and HBeAg seroconversion in 39% (62% monotherapy, 11% intensification). Six patients had HBsAg clearance. Myalgia was more common in the monotherapy group (19% versus 7%). No decrease in the mean glomerular filtration rate occurred in either treatment group at Week 52.
Conclusions: Telbivudine therapy with tenofovir intensification at Week 24, where indicated by the Roadmap strategy, appears effective and well tolerated for the treatment of chronic hepatitis B.
Trial Registration: ClinicalTrials.gov NCT0065120
- ā¦