The effects of hypophysectomy on osmoregulation in the euryhaline flounder Platichthys flesus (L.)

Euryhaline teleostean fish. Inhabit a range of aquatic environments in which the external osmolality varies from less than Im0sm/kg in freshwater to circa l000m0sm/kg in sea water. Teleosts in hypoosmotic media are subject to an osmotic influx of water and a passive efflux of electrolytes, whereas in hyperosmotic conditions these fluxes operate in the reverse direction. Against these adverse effects euryhaline teleosts are able to maintain a regulated internal osmolality within the region of 300m0sm/kg. A homeostatic control of water content and electrolyte composition is achieved by the activities of the three osmo(iono-)regulatory organs - the gill, gut and kidney. A scheme for teleostean osmoregulation was proposed originally by Smith (1930, 1932) and Krogh (l939). Comprehensive reviews of more recent advances in this field are available (Black, 1957; Potts and Parry, 1964; Parry, 1966; Maetz, 1968,1970a; Potts, 1968; Conte, 1969; Hickman and Trump, 1969; Holmes and Donaldson, 1969). In sea water teleosts an osmotic efflux of water is compensated by the drinking and subsequent intestinal absorption of the external medium. Monovalent ions absorbed from the gut are excreted at the gill and divalent ions are lost primarily via the kidney, which also conserves water. In freshwater teleosts drinking is reduced and the osmotic influx of water is excreted by the kidney, which conserves ions to 2 produce a copious, dilute urine. The passive efflux and renal depletion of ions is compensated by their active absorption by the gill from the external medium

Visual symptoms in Parkinson's disease and Parkinson's disease dementia

Non-motor symptoms such as dementia and visual hallucinations are key determinants of long-term outcome and quality of life in Parkinson’s disease (PD). Attempting to understand these issues better was the motivation behind this thesis. A major aim of the study was to characterise the visual symptoms experienced by patients with PD and PD dementia, focussing not just on complex visual hallucinations, whose prognostic implications are already well-described, but also on a range of other visual symptoms including illusory misperceptions, sensations of passage and presence and double vision. A major objective was to define key measures of visual exploration strategy during visuocognitive assessment and examine the link between strategy, cognition and visual and motor symptoms. We also set out to examine the utility of retina-specific visual assessment techniques to define the potential role of retinal dysfunction in visual impairment and symptomatology. A major finding of this study was that not all visual symptoms share a common pathophysiological basis. Our results argue in favour of splitting hallucinations into separate phenomenological groups in order to better define causation and predictive value in future longitudinal studies. In addition, exploration strategy on a variety of visual tasks was demonstrated to be significantly less efficient in subjects with perceptual difficulties, providing insight into the interaction between cognition and eye movements in PD. Retinal structure, as assessed by optical coherence tomography, was not significantly altered in PD and our results would caution against the use of this technique as a disease biomarker until more is known about the limitations of this method. Finally, our neurophysiological assessment hints at the retina as the site of diminished visual acuity in PD despite there being no striking differences in central and peripheral retinal responses between control and PD subjects.EThOS - Electronic Theses Online ServiceParkinson's UK : UK NIHR Biomedical Research Centre for Ageing and Age-Related Disease : Newcastle upon Tyne Hospitals NHS Foundation TrustGBUnited Kingdo

Visual exploration in Parkinson's disease and Parkinson's disease dementia

Parkinson's disease, typically thought of as a movement disorder, is increasingly recognized as causing cognitive impairment and dementia. Eye movement abnormalities are also described, including impairment of rapid eye movements (saccades) and the fixations interspersed between them. Such movements are under the influence of cortical and subcortical networks commonly targeted by the neurodegeneration seen in Parkinson's disease and, as such, may provide a marker for cognitive decline. This study examined the error rates and visual exploration strategies of subjects with Parkinson's disease, with and without cognitive impairment, whilst performing a battery of visuo-cognitive tasks. Error rates were significantly higher in those Parkinson's disease groups with either mild cognitive impairment (P = 0.001) or dementia (P < 0.001), than in cognitively normal subjects with Parkinson's disease. When compared with cognitively normal subjects with Parkinson's disease, exploration strategy, as measured by a number of eye tracking variables, was least efficient in the dementia group but was also affected in those subjects with Parkinson's disease with mild cognitive impairment. When compared with control subjects and cognitively normal subjects with Parkinson's disease, saccade amplitudes were significantly reduced in the groups with mild cognitive impairment or dementia. Fixation duration was longer in all Parkinson's disease groups compared with healthy control subjects but was longest for cognitively impaired Parkinson's disease groups. The strongest predictor of average fixation duration was disease severity. Analysing only data from the most complex task, with the highest error rates, both cognitive impairment and disease severity contributed to a predictive model for fixation duration [F(2,76) = 12.52, P ≤ 0.001], but medication dose did not (r = 0.18, n = 78, P = 0.098, not significant). This study highlights the potential use of exploration strategy measures as a marker of cognitive decline in Parkinson's disease and reveals the efficiency by which fixations and saccades are deployed in the build-up to a cognitive response, rather than merely focusing on the outcome itself. The prolongation of fixation duration, present to a small but significant degree even in cognitively normal subjects with Parkinson's disease, suggests a disease-specific impact on the networks directing visual exploration, although the study also highlights the multi-factorial nature of changes in exploration and the significant impact of cognitive decline on efficiency of visual searc

Down-regulation of mechanisms involved in cell transport and maintenance of mucosal integrity in pigs infected with Lawsonia intracellularis

Lawsonia intracellularis is an obligate intracellular bacterium, responsible for the disease complex known as proliferative enteropathy (PE). L. intracellularis is associated with intestinal crypt epithelial cell proliferation but the mechanisms responsible are yet to be defined. Microarray analysis was used to investigate the host-pathogen interaction in experimentally infected pigs to identify pathways that may be involved. Ileal samples originating from twenty-eight weaner pigs experimentally challenged with a pure culture of L. intracellularis (strain LR189/5/83) were subjected to microarray analysis. Microarray transcriptional signatures were validated using immunohistochemistry and quantitative real time PCR of selected genes at various time points post challenge. At peak of infection (14 days post challenge) 86% of altered transcripts were down regulated, particularly those involved in maintenance of mucosal integrity and regulation of cell transport. Among the up-regulated transcripts, CD163 and CDK1 were novel findings and considered to be important, due to their respective roles in innate immunity and cellular proliferation. Overall, targeted cellular mechanisms included those that are important in epithelial restitution, migration and protection; maintenance of stable inter-epithelial cell relationships; cell transport of nutrients and electrolytes; innate immunity; and cell cycle

Blood culture collection technique and pneumococcal surveillance in Malawi during the four year period 2003–2006: an observational study

BACKGROUND: Blood culture surveillance will be used for assessing the public health effectiveness of pneumococcal conjugate vaccines in Africa. Between 2003 and 2006 we assessed blood culture outcome and performance in adult patients in the central public hospital in Blantyre, Malawi, before and after the introduction of a dedicated nurse led blood culture team. METHODS: A prospective observational study. RESULTS: Following the introduction of a specialised blood culture team in 2005, the proportion of contaminated cultures decreased (19.6% in 2003 to 5.0% in 2006), blood volume cultured increased and pneumococcal recovery increased significantly from 2.8% of all blood cultures to 6.1%. With each extra 1 ml of blood cultured the odds of recovering a pneumococcus increased by 18%. CONCLUSION: Standardisation and assessment of blood culture performance (blood volume and contamination rate) should be incorporated into pneumococcal disease surveillance activities where routine blood culture practice is constrained by limited resources

Crystal structure of dichlorido(4,11-dimethyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane)iron(III) hexafluoridophosphate

The title compound, [FeCl₂(C₁₄H₃₀N₄)]PF₆, contains Fe³⁺ coordinated by the four nitro­gen atoms of an ethyl­ene cross-bridged cyclam macrocycle and two cis chloride ligands in a distorted octa­hedral environment. In contrast to other similar compounds this is a monomer. Inter­molecular C-H...Cl inter­actions exist in the structure between the complex ions. Comparison with the mononuclear Fe²⁺ complex of the same ligand shows that the smaller Fe³⁺ ion is more fully engulfed by the cavity of the bicyclic ligand. Comparison with the μ-oxido dinuclear complex of an unsubstituted ligand of the same size demonstrates that the methyl groups of 4,11-dimethyl-1,4,8,11-tetra­aza­bicyclo­[6.6.2]hexa­decane prevent dimerization upon oxidation

Placing Joseph Banks in the North Pacific

The South Pacific was a fulcrum of Joseph Banks's maritime world and global networks. The North Pacific was a distance and intangible fringe. This article is concerned with how Banks should be ‘placed’ in the North Pacific. It tracks how Banks's activities have been delineated in terms of languages and categories of global and local, and centre and margin, and then considers the historical and geographical specifics apposite to his connection to the North Pacific. In this setting, ideas of place (as location and assignment) and capital (as a circulatory and everyday practice of exchange and opportunism) come into view and question the distinction between science and commerce in Banks historiography. The article considers a diverse group of non-Indigenous figures – explorers, traders, cartographers, scientists, collectors – operating in the North Pacific in the 1780s and 1790s whose initiatives and missives passed across Banks's desk, and assesses their place in Banks's archive by drawing on Peter Sloterdijk's ideas about the interiorising and exteriorising logic of capital.PostprintPeer reviewe