65 research outputs found

    Coupled stalagmite – Alluvial fan response to the 8.2 ka event and early Holocene palaeoclimate change in Greece

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    We explore the expression of early Holocene climatic change in the terrestrial Mediterranean of southern Greece. A regional palaeoclimate record from stable isotope and trace element geochemical proxies in an early Holocene (~12.4 ka to 6.7 ka) stalagmite is compared to the timing of palaeosol (entisol) development on an early Holocene alluvial fan located <100 km from the stalagmite site. Radiocarbon dated entisol development records fan abandonment surfaces, which can be coupled to the stalagmite climate signal. Variations in δ13C best record the main elements of palaeoclimatic change, more negative values indicating soil carbon input to karst groundwater under wetter conditions. The wettest conditions begin around 10.3 ka, coincident with the start of sapropel 1 deposition in the eastern Mediterranean. The widely documented northern hemisphere ‘8.2 ka event’ of cooler and drier conditions has a muted δ18O climatic signal in common with other stalagmite climate records from the wider Mediterranean. However, less negative δ13C values do record a period of episodic dryness between ~8.8 and ending at 8.2 ka. Wetter conditions re-established after 8.1 ka to the end of the record. The oldest alluvial fan entisols were developing by ~9.5 ka, and a prominent rubified entisol developed ~8.3 to 8.4 ka, indicating pedogenesis within dating error of the 8.2 ka event. The speleothem record of episodic dryness between ~8.8 and 8.2 ka, combined with other regional proxies, is consistent with the notion that precipitation patterns in Greece may have changed from predominantly winter frontal to summer convective during this period. Palaeosol formation on the alluvial fan may have been an allocyclic response to this change. It is plausible that fan-channel incision, driven by temporary development of a ‘flashier’ summer rainfall regime, isolated large areas of the fan surface allowing onset of prolonged pedogenesis there

    Hyperplastic goitre and mortality in captive-reared black stilts (Himantopus novaezelandiae)

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    AIM: To study the gross, histopathological and clinicopathological findings in cases of hyperplastic goitre in sub-adult captive-reared black stilts following their release on riverbeds in the south Canterbury region of New Zealand. METHODS: Necropsies were undertaken on the recovered carcasses of 48 black stilts over a 3-year period (1997–1999). The cause of death was determined, and thyroid glands were examined histopathologically and compared with those of free-living pied stilts. Concentrations of triiodothyronine (T3) and thyroxine (T4) in the serum of sub-adult and adult stilts were measured before and after iodine supplementation. RESULTS: The main causes of death of captive-reared black stilts following release were trauma, predation and starvation. An increase in size of the thyroid gland due to follicular hyperplasia and dilation was seen in all birds with intact thyroid glands (n=27). Dysplastic follicular changes such as epithelial desquamation, lipid deposition and haemorrhage were common in a large proportion of individuals with goitre. Dietary supplementation with iodine greatly improved survival rates in sub-adults following release, and significantly increased concentrations of T3 and T4 in serum. CONCLUSIONS: Subclinical goitre due to thyroid hyperplasia and dysplasia was the cause of hypothyroidism and this contributed to the poor survival of released sub-adult black stilts raised in captivity. Iodine supplementation of the diet of captive adults and sub-adults resulted in increased concentrations of T3 and T4 in serum and improved survivability

    Adenomatous hyperplasia of the mucous glands in captive Archey's frogs (Leiopelma archeyi)

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    Aims: To describe the gross and light microscopic characteristics of skin lesions observed on the ventral skin of captive Archey's frogs (Leiopelma archeyi) between 2000 and 2012, and to investigate their occurrence, possible aetiology and association with survival.\ud \ud Methods: Postmortem skin samples were obtained for histological evaluation from 37 frogs, with and without skin lesions, that died while in captivity at Auckland Zoo between 2000 and 2012. Four frogs with skin lesions were biopsied under general anaesthesia and samples used for both light and transmission electron microscopy. The records of 94 frogs held at the University of Otago and Auckland Zoo between 2000–2012 were reviewed, which included some frogs recently collected from the wild. Information about the occurrence of skin lesions, and mortality associated with skin lesions was collated.\ud \ud Results: Grossly the skin lesions varied in appearance; most were circular, pale grey papules, which measured from <0.5–1.5 mm in diameter with no umbilication. The overlying epidermis was not fragile and there was no associated inflammation. Contents often appeared clear or semi-transparent. Lesions were located predominantly on ventral surfaces including trunk, thighs, lower legs and forearms, and gular region, but not on digits. The number ranged from single to multiple, often confluent lesions covering the entire ventral surface of the frog. Histologically the lesions consisted of enlarged proliferating mucous glands that expanded the dermis and elevated the epidermis. They were semi-organised, solid or occasionally cavitated acinar structures with central lumina which sometimes contained mucus. Nuclei showed moderate anisokaryosis and mitotic figures were uncommon. Transmission electron microscopy did not show any infectious agents. Between 2000 and 2012, skin lesions were recorded in 35/94 (37%) frogs. The size and location of skin lesions varied over time, with some resolving and sometimes reappearing. Skin lesions were not associated with an increased risk of death.\ud \ud Conclusions: The skin lesions had the gross and microscopic characteristics of adenomatous hyperplasia of the dermal mucous glands.\ud \ud Clinical relevance: The aetiology of this adenomatous hyperplasia is unknown, but factors associated with the captive environment are the most likely cause. This is the first description of adenomatous hyperplasia of the cutaneous mucous glands in amphibians

    Investigation of mortalities associated with Salmonella spp. infection in wildlife on Tiritiri Matangi Island in the Hauraki Gulf of New Zealand

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    CASE HISTORY: Salmonellosis was suspected as the cause of death in eight wild animals on Tiritiri Matangi Island, in the Hauraki Gulf of New Zealand, between November and September 2011, including three hihi (Notiomystis cincta), a tuatara (Sphenodon punctatus), a masked lapwing (Vanellus miles novaehollandiae), and a saddleback (Philesturnus carunculatus). An outbreak investigation to identify the source and distribution of infection was undertaken over the summer of 2011–2012. CLINICAL AND LABORATORY FINDINGS: Surveillance of five species of forest bird (n=165) in December 2011 returned a single positive result for Salmonella spp. Environmental sampling of 35 key water sources and hihi supplementary feeding stations conducted in December 2011 and March 2012 returned isolates of S. enterica subspecies houtenae and S. enterica serovar Saintpaul from a stream, a dam and a supplementary feeding station. The same serotypes were identified in tissue samples collected from post mortem specimens of the affected birds, and their similarity was confirmed by pulsed-field gel electrophoresis. DIAGNOSIS: Mortality in wildlife associated with infection with S. enterica subspecies houtenae and S. enterica serovar Saintpaul. CLINICAL RELEVANCE: This is the first detection of these Salmonella spp. from wild birds in New Zealand. Our study highlights how active surveillance in response to observed disease emergence (here mortalities) can provide important insight for risk assessment and management within populations of endangered species and inform risk assessment in translocation planning

    Identifying bias in CCR1 antagonists using radiolabelled binding, receptor internalization, β-arrestin translocation and chemotaxis assays.

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    BACKGROUND AND PURPOSE: Investigators have suggested that the chemokine receptor CCR1 plays a role in multiple myeloma. Studies using antisense and neutralizing antibodies to CCR1 showed that down-regulation of the receptor altered disease progression in a mouse model. More recently, experiments utilizing scid mice injected with human myeloma cells demonstrated that the CCR1 antagonist BX471 reduced osteolytic lesions, while the CCR1 antagonist MLN-3897 prevented myeloma cell adhesion to osteoclasts. However, information is limited regarding the pharmacology of CCR1 antagonists in myeloma cells. EXPERIMENTAL APPROACH: We compared several well-studied CCR1 antagonists including AZD4818, BX471, CCX354, CP-481715, MLN-3897 and PS899877 for their ability to inhibit binding of [(125)I]-CCL3 in vitro using membranes prepared from RPMI 8226 cells, a human multiple myeloma cell line that endogenously expresses CCR1. In addition, antagonists were assessed for their ability to modulate CCL3-mediated internalization of CCR1 and CCL3-mediated cell migration using RPMI 8226 cells. As many GPCRs signal through β-arrestin-dependent pathways that are separate and distinct from those driven by G-proteins, we also evaluated the compounds for their ability to alter β-arrestin translocation. KEY RESULTS: There were clear differences between the CCR1 antagonists in their ability to inhibit CCL3 binding to myeloma cells, as well as in their ability to inhibit G-protein-dependent and -independent functional responses. CONCLUSIONS AND IMPLICATIONS: Our studies demonstrate that tissue phenotype seems to be relevant with regards to CCR1. Moreover, it appears that for CCR1 antagonists, inhibition of β-arrestin translocation is not necessarily linked to chemotaxis or receptor internalization
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