Alterations in renal and myocardial adrenoceptors associated with ethynyloestradiol- and levonorgestrel-induced hypertension in the rat

Hypertension is one of many side effects of oral contraceptive use in a small percentage of women. Although the underlying pathology has yet to be fully resolved, alterations in the renin-angiotensin-aldosterone axis, sympathetic nervous system/ renal and cardiac function have been implicated. In the thesis to be presented, the possible involvement of alterations in renal and myocardial adrenoceptor characteristics in the pathogenesis of steroid contraceptive-induced hypertension in rats was examined by radioligand binding techniques. In Chapter 2, a rat model of OC hypertension is described. Chronic low-dose administration of ethynyloestradiol (EE2), levonorgestrel (NG) or a combination of both steroids (EE2/NG) to female Sprague-Dawley rats was shown to significantly increase systolic blood pressure (SBP). Renal and cardiac hypertrophy developed in association with EE2-, EE2/NG- but not NG-induced hypertension. Moreover, whereas administration of NG alone attenuated body weight gain, combined EE2/NG administration increased body weight gain from the second week of treatment onwards. Based on the above observations, it is proposed that EE2 and NG induce hypertension in rats via different mechanisms. Although SBP was elevated to a similar maximum in all steroid-treated groups (+ 20 mmHg compared to controls), only with EE2 administration did SBP remain elevated for the duration of the 17 week treatment regimen. NG may therefore have a protective effect on blood pressure with long-term combined steroid contraceptive treatment. In Chapter 4, renal adrenoceptors were characterized using radioactively labelled adrenocephor antagonists. Under appropriate conditions, binding of [3H]-prazosin and [3H]-rauwolscine to membrane preparations of whole rat kidney displayed the kinetics, saturability and specificity of α1- and α2 -adrenoceptors respectively, which were present in a ratio 3:1. In contrast, [3H]-dihydroergocryptine ([3H]-DHE) apparently bound to both α1 and α2-adrenoceptors. Binding sites identified by [125I] –iodocyanopindolol (ICYP) had the recognition characteristics of β-adrenoceptors. In drug competition studies using the subtype-selective antagonists practolol (β1) and ICI 118,551 (β2)/ the ratio of β1- to β2 -adrenoceptors was found to be approximately 2:1. Subsequently, renal adrenoceptors were investigated at various stages during the development of hypertension with the different steroid contraceptive treatments (Chapters 5 and 6). Preliminary binding studies with [3H]-DHE and [3H]-prazosin suggested that the number of renal α2 - but not α1-adrenoceptors was reduced in rats with established EE2-induced hypertension (17 weeks treatment). This was subsequently confirmed using [3H]-rauwolscine, which in addition showed that the reduction in renal α2 -adrenoceptor number occurred during the developmental stage of EE2/NG~induced hypertension (6 weeks treatment) and established EE2-induced hypertension (12 weeks treatment). NG induced hypertension was unassociated with changes in renal α1- and α2-adrenoceptor characteristics. Renal β-adrenoceptor affinity was reduced in established EE2-, but not NG- or EE2/NG- induced hypertension. Moreover, the β-adrenoceptor agonist (-)-isoprenaline bound to renal β-adrenoceptors with reduced affinity following EE2 administration. Several endogenous and synthetic steroids were found to be ineffective inhibitors of [3H] –prazosin, [3H] –rauwolscine and ICYP binding excluding a direct interaction of these steroids with renal α1-, α2- and β -adrenoceptors. In Chapter 7, myocardial adrenoceptors were characterized and investigated in steroid-treated rats. In membrane preparations of whole myocardium, [3H]-prazosin binding was characteristically to α1- adrenoceptors, whereas there was a notable absence of [3H]-rauwolscine binding. Using ICYP, β-adrenoceptors were also detected, the ratio of β1- to β2~adrenoceptors being 3:1. Steroid contraceptive-induced hypertension was not associated with myocardial α1-adrenoceptor changes. Similarly, myocardial β-adrenoceptors were unchanged in established EE2-, NG- and EE2/NG-induced hypertension (12 weeks treatment). The affinity of (-)-isoprenaline for myocardial β-adrenoceptors was unaffected by EE2 aditiinistration. These studies suggest that established EE2- but not NG-induced hypertension in rats is associated with selective alterations in renal α2- and (β-adrenoceptors. These adrenoceptor changes may help to maintain elevated blood pressure by affecting the control of renal function by the sympathetic nervous system, catecholamines and several hormones which affect renin release and the transport of fluid and electrolytes in the nephron

Entry pathways of herpes simplex virus type 1 into human keratinocytes are dynamin- and cholesterol-dependent

Herpes simplex virus type 1 (HSV-1) can enter cells via endocytic pathways or direct fusion at the plasma membrane depending on the cell line and receptor(s). Most studies into virus entry have used cultured fibroblasts but since keratinocytes represent the primary entry site for HSV-1 infection in its human host, we initiated studies to characterize the entry pathway of HSV-1 into human keratinocytes. Electron microscopy studies visualized free capsids in the cytoplasm and enveloped virus particles in vesicles suggesting viral uptake both by direct fusion at the plasma membrane and by endocytic vesicles. The ratio of the two entry modes differed in primary human keratinocytes and in the keratinocyte cell line HaCaT. Inhibitor studies further support a role for endocytosis during HSV-1 entry. Infection was inhibited by the cholesterol-sequestering drug methyl-beta-cyclodextrin, which demonstrates the requirement for host cholesterol during virus entry. Since the dynamin-specific inhibitor dynasore and overexpression of a dominant-negative dynamin mutant blocked infection, we conclude that the entry pathways into keratinocytes are dynamin-mediated. Electron microscopy studies confirmed that virus uptake is completely blocked when the GTPase activity of dynamin is inhibited. Ex vivo infection of murine epidermis that was treated with dynasore further supports the essential role of dynamin during entry into the epithelium. Thus, we conclude that HSV-1 can enter human keratinocytes by alternative entry pathways that require dynamin and host cholesterol

Buried Ion-Exchanged Glass Wavelengths: Burial-Depth Dependence on Waveguide Width

A detailed theoretical and experimental study of the depth dependence of buried ion-exchanged waveguides on waveguide width is reported. Modeling, which includes the effect of nonhomogeneous time-dependent electric field distribution, agrees well with our experiments showing that burial depth increases linearly with waveguide width. These results may be used in the proper design of integrated optical circuits that need waveguides of different widths at different sections, such as arrayed waveguide gratings

Socioecological model-based design and implementation principles of Lower Limb Preservation Programs as partners for Limb-loss Rehabilitation Programs- A mini-review

People with lower limb loss, especially of dysvascular etiology, are at substantial risk for both ipsilateral and contralateral reamputation. Additionally, while not as well documented for reamputation, there is recognition that amputation incidence is influenced by not only sociodemographic factors such as sex, race, socioeconomic status, but also by system factors such as service access. A systems strategy to address this disparity within the field of limb-loss rehabilitation is for Limb-loss Rehabilitation Programs (LRP) to partner with medical specialists, mental health professionals, and Limb Preservation Programs (LPP) to provide comprehensive limb care. While LPPs exist around the nation, design principles for such programs and their partnership role with LRPs are not well established. Using a socioecological model to incorporate hierarchical stakeholder perspectives inherent in the multidisciplinary field of limb care, this review synthesizes the latest evidence to focus on LPP design and implementation principles that can help policymakers, healthcare organizations and limb-loss rehabilitation and limb-preservation professionals to develop, implement, and sustain robust LPP programs in partnership with LRPs

'Another, More Sinister Reality': Class, Youth and Psychopathology from Saturday Night and Sunday Morning to Endless Night

This article analyses how the protagonists of films such as Saturday Night and Sunday Morning (1959), The Collector (1965), Blow Up (1966), Twisted Nerve (1968) and Endless Night (1972) were understood in relation to debates over the supposed perils of the new affluence and the erosion of class distinctions that it was presumed to entail. In particular it examines the terms in which these issues were discussed within contemporaneous reviews of the films, terms that were insistently psychological. These protagonists, as well as, to a certain extent, the actors who played them, were seen as representing a nightmare image of a ‘new’ working class that no longer ‘knew its place’, and as manifesting psychological problems that were associated with this intermediate status. Their psychologies were interpreted by many critics as being distinguished by a sense of isolation from external reality and by a hostile relationship to the world characterised by a psychopathic lack of empathy. Such concerns could be seen as establishing certain parallels between working-class realism and the contemporaneous horror film, and indeed the reviews cited in this article demonstrate that working-class realism and horror were seen as having shared points of interest in the 1960s, points that have often been repressed by the tendency to compartmentalise British cinema history into separate or even opposed ‘traditions’

Guidelines for the use of cell lines in biomedical research

Cell-line misidentification and contamination with microorganisms, such as mycoplasma, together with instability, both genetic and phenotypic, are among the problems that continue to affect cell culture. Many of these problems are avoidable with the necessary foresight, and these Guidelines have been prepared to provide those new to the field and others engaged in teaching and instruction with the information necessary to increase their awareness of the problems and to enable them to deal with them effectively. The Guidelines cover areas such as development, acquisition, authentication, cryopreservation, transfer of cell lines between laboratories, microbial contamination, characterisation, instability and misidentification. Advice is also given on complying with current legal and ethical requirements when deriving cell lines from human and animal tissues, the selection and maintenance of equipment and how to deal with problems that may arise

Supporting Self-management Among Young People With Acne Vulgaris Through a Web-Based Behavioral Intervention: Development and Feasibility Randomized Controlled Trial

Background: Acne is a common skin condition that is most prevalent in young people. It can have a substantial impact on the quality of life, which can be minimized with the appropriate use of topical treatments. Nonadherence to topical treatments for acne is common and often leads to treatment failure. Objective: The aim of this study is to develop a web-based behavioral intervention to support the self-management of acne and to assess the feasibility of recruitment, retention, and engagement of users with the intervention. Methods: The intervention was developed iteratively using the LifeGuide software and following the person-based approach for intervention development. The target behavior was appropriate use of topical treatments. Barriers and facilitators identified from the qualitative research and evidence from the wider literature were used to identify techniques to improve and promote their use. Young people with acne aged 14-25 years who had received treatment for acne in the past 6 months were invited to participate through mail-out from primary care practices in the South of England in a parallel, unblinded randomized trial. Participants were automatically randomized using a computer-generated algorithm to usual care or to usual care plus access to the web-based intervention. Usage data was collected, and a series of questionnaires, including the primary outcome measure for skin-specific quality of life (Skindex-16), were collected at baseline and at the 4- and 6-week follow-ups. Results: A total of 1193 participants were invited, and 53 young people with acne were randomized to usual care (27/53, 51%) or usual care plus intervention (26/53, 49%). The response rate for the primary outcome measure (Skindex-16) was 87% at 4 weeks, 6 weeks, and at both time points. The estimate of mean scores between groups (with 95% CI) using linear regression showed a trend in the direction of benefit for the web-based intervention group in the primary outcome measure (Skindex-16) and secondary measures (Patient Health Questionnaire-4 and the Problematic Experiences of Therapy Scale). Intervention usage data showed high uptake of the core module in the usual care plus web-based intervention group, with 88% (23/26) of participants completing the module. Uptake of the optional modules was low, with less than half visiting each (myth-busting quiz: 27%; living with spots or acne: 42%; oral antibiotics: 19%; what are spots or acne: 27%; other treatments: 27%; talking to your general practitioner: 12%). Conclusions: This study demonstrated the feasibility of delivering a trial of a web-based intervention to support self-management in young people with acne. Additional work is needed before a full definitive trial, including enhancing engagement with the intervention, recruitment, and follow-up rates