10 research outputs found
Octopamine underlies the counter-regulatory response to a glucose deficit in honeybees (Apis mellifera)
An animal’s internal state is a critical parameter required for adaptation to
a given environment. An important aspect of an animal’s internal state is the
energy state that is adjusted to the needs of an animal by energy homeostasis.
Glucose is one essential source of energy, especially for the brain. A
shortage of glucose therefore triggers a complex response to restore the
animal’s glucose supply. This counter-regulatory response to a glucose deficit
includes metabolic responses like the mobilization of glucose from internal
glucose stores and behavioral responses like increased foraging and a rapid
intake of food. In mammals, the catecholamines adrenalin and noradrenalin take
part in mediating these counter-regulatory responses to a glucose deficit. One
candidate molecule that might play a role in these processes in insects is
octopamine (OA). It is an invertebrate biogenic amine and has been suggested
to derive from an ancestral pathway shared with adrenalin and noradrenalin.
Thus, it could be hypothesized that OA plays a role in the insect’s counter-
regulatory response to a glucose deficit. Here we tested this hypothesis in
the honeybee (Apis mellifera), an insect that, as an adult, mainly feeds on
carbohydrates and uses these as its main source of energy. We investigated
alterations of the hemolymph glucose concentration, survival, and feeding
behavior after starvation and examined the impact of OA on these processes in
pharmacological experiments. We demonstrate an involvement of OA in these
three processes in honeybees and conclude there is an involvement of OA in
regulating a bee’s metabolic, physiological, and behavioral response following
a phase of prolonged glucose deficit. Thus, OA in honeybees acts similarly to
adrenalin and noradrenalin in mammals in regulating an animal’s counter-
regulatory response
Bioavailability of silver from wastewater and planktonic food borne silver nanoparticles in the rainbow trout Oncorhynchus mykiss
Comparative multi-generation study on long-term effects of pristine and wastewater-borne silver and titanium dioxide nanoparticles on key lifecycle parameters in Daphnia magna
Chronic effects of wastewater-borne silver and titanium dioxide nanoparticles on the rainbow trout (Oncorhynchus mykiss)
Impact of wastewater-borne nanoparticles of silver and titanium dioxide on the swimming behaviour and biochemical markers of Daphnia magna: An integrated approach
Due to their widespread use, silver (Ag) and titanium dioxide (TiO2) nanoparticles (NPs) are commonly discharged into aquatic environments via wastewater treatment plants. The study was aimed to assess the effects of wastewater-borne AgNPs (NM-300 K; 15.5 ± 2.4 nm; 25−125 μg L−1) and TiO2NPs (NM-105; 23.1 ± 6.2 nm; 12.5−100 μg L−1), from a laboratory-scale wastewater treatment plant, on Daphnia magna, at individual and subcellular level. For effect comparison, animals were also exposed to ASTM-dispersed NPs at the same nominal concentrations. The behaviour of D. magna was evaluated through monitoring of swimming height and allocation time for preferred zones after 0 h and 96 h of exposure. Biochemical markers of neurotransmission, anaerobic metabolism, biotransformation, and oxidative stress were subsequently determined. No 96-h EC50 (immobilization ≤ 4 %) could be obtained with wastewater-borne NPs and ASTM-dispersed TiO2NPs, whereas the ASTM-dispersed AgNPs resulted in an immobilization 96-h EC50 of 113.8 μg L−1. However, both wastewater-borne and ASTM-dispersed TiO2NPs, at 12.5 μg L−1, caused immediate (0 h) alterations on the swimming height. Allocation time analyses showed that animals exposed to ASTM-dispersed AgNPs spent more time on the surface and bottom at 0 h, and in the middle and bottom at 96 h. This pattern was not observed with ASTM-dispersed TiO2NPs nor with wastewater-borne AgNPs and wastewater-borne TiO2NPs. At the biochemical level, the more pronounced effects were observed with wastewater-borne AgNPs (e.g. induction of lactate dehydrogenase and glutathione S-transferase activities, and inhibition of catalase activity). This integrative approach showed that: (i) the behavioural and biochemical response-patterns were distinct in D. magna exposed to environmentally relevant concentrations of wastewater-borne and ASTM-dispersed NPs; (ii) the most pronounced effects on allocation time were induced by ASTM-dispersed AgNPs; and (iii) at the subcellular level, wastewater-borne AgNPs were more toxic than wastewater-borne TiO2NPs. This study highlights the need for the assessment of the effects of wastewater-borne NPs under realistic exposure scenarios, since processes in wastewater treatment plants may influence their toxicity
Thrombolytic and Antiplatelet Therapy in Peripheral Vascular Disease with Use of Reteplase and/or Abciximab
Octopamine Underlies the Counter-Regulatory Response to a Glucose Deficit in Honeybees (Apis mellifera)
A review of central retinal artery occlusion: clinical presentation and management
Central retinal artery occlusion (CRAO) is an ophthalmic emergency and the ocular analogue of cerebral stroke. Best evidence reflects that over three-quarters of patients suffer profound acute visual loss with a visual acuity of 20/400 or worse. This results in a reduced functional capacity and quality of life. There is also an increased risk of subsequent cerebral stroke and ischaemic heart disease. There are no current guideline-endorsed therapies, although the use of tissue plasminogen activator (tPA) has been investigated in two randomized controlled trials. This review will describe the pathophysiology, epidemiology, and clinical features of CRAO, and discuss current and future treatments, including the use of tPA in further clinical trials.DD Varma, S Cugati, AW Lee, and CS Che