Modeling the synergy between HSV-2 and HIV and potential impact of HSV-2 therapy

Mounting evidence indicates that genital HSV-2 infection may increase susceptibility to HIV infection and that co-infection may increase infectiousness. Accordingly, antiviral treatment of people with HSV-2 may mitigate the incidence of HIV in populations where both pathogens occur. To better understand the epidemiological synergy between HIV and HSV-2, we formulate a deterministic compartmental model that describes the transmission dynamics of these pathogens. Unlike earlier models, ours incorporates gender and heterogeneous mixing between activity groups. We derive explicit expressions for the reproduction numbers of HSV-2 and HIV, as well as the invasion reproduction numbers via next generation matrices. A qualitative analysis of the system includes the local and global behavior of the model. Simulations reinforce these analytical results and demonstrate epidemiological synergy between HSV-2 and HIV. In particular, numerical results show that HSV-2 favors the invasion of HIV, may dramatically increase the peak as well as reducing the time-to-peak of HIV prevalence, and almost certainly has exacerbated HIV epidemics. The potential population-level impact of HSV-2 on HIV is demonstrated by calculating the fraction of HIV infections attributable to HSV-2 and the difference between HIV prevalence in the presence and absence of HSV-2. The potential impact of treating people with HSV-2 on HIV control is demonstrated by comparing HIV prevalence with and without HSV-2 therapy. Most importantly, we illustrate that the aforementioned aspects of the population dynamics can be significantly influenced by the sexual structure of the population.     

Building cross‐cultural coalitions: A case‐study of the Black‐Korean Alliance and the Latino‐Black Roundtable

A case‐study is presented of two Los Angeles‐based cross‐cultural coalitions, the Black‐Korean Alliance [BKA] and the Latino‐Black Roundtable [LBR]. An analysis of the development and eventual dissolution of these two coalitions is presented against the backdrop of the history of relations between the African‐American, Korean‐American and Latino communities of Los Angeles. The central issues leading to the breakup of the two coalitions were: lack of resources, internal power dynamics between coalition partners, nationalistic factions within the broader communities, cross‐cultural dynamics between coalition members, the use of a dialogue model to frame coalition activities, and the analysis of intergroup relations underlying the formation of the coalitions. The applied and theoretical implications of the research are discussed.     

A typology of arguments in defence of a coercive language policy favouring a cultural minority

Abstract

What kind of arguments can be used to justify a coercive language policy favouring the language of a cultural minority over the majority language of a state? To answer this question we will focus mainly on the language policy of the Catalan government and, to a lesser extent, on the language policies of the Basque Country and Quebec. Our aim is to develop a typology of arguments and try to show that each argument resorts to a different reason for coercion and has both virtues and flaws.     

Novel model for “calcium paradox” in sympathetic transmission of smooth muscles: Role of cyclic AMP pathway

It is well established that reduction of Ca²⁺ influx through L-type voltage-dependent Ca²⁺ channel (L-type VDCC), or increase of cytosolic cAMP concentration ([cAMP]c), inhibit contractile activity of smooth muscles in response to transmitters released from sympathetic nerves. Surprisingly, in this work we observed that simultaneous administration of L-type VDCC blocker (verapamil) and [cAMP]c enhancers (rolipram, IBMX and forskolin) potentiated purinergic contractions evoked by electrical field stimulation of rat vas deferens, instead of inhibiting them. These results, including its role in sympathetic transmission, can be considered as a “calcium paradox”. On the other hand, this potentiation was prevented by reduction of [cAMP]c by inhibition of adenylyl cyclase (SQ 22536) or depletion of Ca²⁺ storage of sarco-endoplasmic reticulum by blockade of Ca²⁺ reuptake (thapsigargin). In addition, cytosolic Ca²⁺ concentration ([Ca²⁺]_c) evaluated by fluorescence microscopy in rat adrenal medullary slices was significantly reduced by verapamil or rolipram. In contrast, simultaneous incubation of adrenal slices with these compounds significantly increased [Ca²⁺]_c. This effect was prevented by thapsigargin. Thus, a reduction of [Ca²⁺]_c due to blockade of Ca²⁺ influx through L-type VDCC could stimulate adenylyl cyclase activity increasing [cAMP]c thereby stimulating Ca²⁺ release from endoplasmic reticulum, resulting in augmented transmitter release in sympathetic nerves and contraction.     

Effects of Hypomagnetic Field on Magnetosome Formation of Magnetospirillum Magneticum AMB-1

Magnetotactic bacteria synthesize intracellular magnetic particles, magnetosomes, which arrange in chain(s) and confer on cell a magnetic dipolar moment. To explore the function of geomagnetic field to magnetotactic bacteria, the effects of hypomagnetic field on magnetosome formation in Magnetospirillum magneticum AMB-1 were studied. Cells were cultivated in a specially designed device where geomagnetic field was reduced by about 100-fold to less than 500nT. AMB-1 cultures were incubated in hypomagnetic field or geomagnetic field. Results showed that hypomagnetic field had no significant effects on the average number of magnetic particles per bacterium and bacterial iron depletion. However, the growth (OD) of cell at stationary-phase was lower and cellular magnetism (R _mag) at exponential growth phase was higher than that of bacteria cultivated in geomagnetic field. Statistic results on transmission electron microscopy (TEM) micrographs showed that the average size of magnetic particles in AMB-1 cells in hypomagnetic field group was larger than that of in geomagnetic field group and more ratio of larger-size magnetic particles (>50 nm) was observed when cultivated 16 h under hypomagnetic field. Furthermore, the influences of hypomagnetic field on gene expression were studied in AMB-1 cells. Quantitative RT-PCR results showed that hypomagnetic field up-regulated mms13, down-regulated mms6 and had no effect on magA. Together, the results showed that hypomagnetic field could affect the growth of AMB-1 at the stationary-phase, the crystallization process of magnetosomes, and mms13, mms6 expressions. In addition, our results suggested that the geomagnetic field plays an important role in the biomineralization of magnetosomes.     

Distinct intrinsic and synaptic properties of pre‐sympathetic and pre‐parasympathetic output neurons in Barrington's nucleus

Barrington's nucleus (BN), commonly known as the pontine micturition center, controls micturition and other visceral functions through projections to the spinal cord. In this study, we developed a rat brain slice preparation to determine the intrinsic and synaptic mechanisms regulating pre‐sympathetic output (PSO) and pre‐parasympathetic output (PPO) neurons in the BN using patch‐clamp recordings. The PSO and PPO neurons were retrogradely labeled by injecting fluorescent tracers into the intermediolateral region of the spinal cord at T13‐L1 and S1‐S2 levels, respectively. There were significantly more PPO than PSO neurons within the BN. The basal activity and membrane potential were significantly lower in PPO than in PSO neurons, and A‐type K⁺ currents were significantly larger in PPO than in PSO neurons. Blocking A‐type K⁺ channels increased the excitability more in PPO than in PSO neurons. Stimulting μ‐opioid receptors inhibited firing in both PPO and PSO neurons. The glutamatergic EPSC frequency was much lower, whereas the glycinergic IPSC frequency was much higher, in PPO than in PSO neurons. Although blocking GABA_A receptors increased the excitability of both PSO and PPO neurons, blocking glycine receptors increased the firing activity of PPO neurons only. Furthermore, blocking ionotropic glutamate receptors decreased the excitability of PSO neurons but paradoxically increased the firing activity of PPO neurons by reducing glycinergic input. Our findings indicate that the membrane and synaptic properties of PSO and PPO neurons in the BN are distinctly different. This information improves our understanding of the neural circuitry and central mechanisms regulating the bladder and other visceral organs.     

Cortical GluK1 kainate receptors modulate scratching in adult mice

Recent investigations into the mechanisms mediating itch transmission have focused on spinal mechanisms, whereas few studies have investigated the role of the cerebral cortex in itch‐related behaviors. Human imaging studies show that several cortical regions are active in correspondence with itch, including the anterior cingulate cortex (ACC). We present here evidence of cortical modulation of pruritogen‐induced scratching behavior. We combine pharmacological, genetic, and electrophysiological approaches to show that cortical GluK1‐containing kainate (KA) receptors are involved in scratching induced by histamine and non‐histamine‐dependent itching stimuli. We further show that scratching corresponds with enhanced excitatory transmission in the ACC through KA receptor modulation of inhibitory circuitry. In addition, we found that inhibiting GluK1‐containing KA receptors in the ACC also reduced behavioral nociceptive responses induced by formalin. Our results reveal a new role of the cortex in pruritogen‐induced scratching.

     

Darker female pigeons transmit more specific antibodies to their eggs than do paler ones

Melanin‐based coloration is widespread among vertebrates, yet the adaptive significance of such pigments remains elusive, particularly with regard to the link between melanin and immune‐mediated maternal effects. The aim of this study was to investigate whether melanin‐based coloration could signal the ability of mothers to mount a humoral response and to transfer maternal antibodies (Ab) to their young. We injected differently coloured (pale and dark) female feral pigeons (Columba livia) with Chlamydiae (a natural antigen) and Keyhole Limpet Haemocyanin (KLH, an artificial antigen), and found no significant difference in humoral response between differently coloured females. However, darker females transferred more Ab against Chlamydiae into their eggs than paler ones, despite similar circulating levels of Ab. In addition to this, melanin‐based coloration showed a high heritability value. This suggests that a genetically based coloured trait might be linked to the ability of females to transfer specific Ab against Chlamydiae (but not against KLH) to their offspring, independent of their ability to produce Ab. This suggests that transmission of maternal Ab is antigen dependent, and that melanin‐based coloration might signal female ability to transmit specific Ab against natural pathogens. © 2013 The Linnean Society of London     

Vom Ruhr Zoo zur ZOOM Erlebniswelt III: Der Bauabschnitt Asien

In the Zoom Erlebniswelt Gelsenkirchen the third and last biogeographical area dedicated to the Asian fauna was opened in March 2010 covering a total area of five hectares. In May 2013 a new enclosure for tigers was added. The emphasis of the Asia area lies on a 4700 m² tropical hall with mammals and birds, and Asian gastronomic facilities as well. Included is a mixed species exhibit for orangutans (Pongo abelii), northern plains grey langurs (Semnopithecus entellus) and Asian small clawed otters (Aonyx cinerea). Along a 1.3 km outside path enclosures for some species of colder climates were built, too. The transformation of the former Ruhr Zoo Gelsenkirchen to the modern ZOOM Erlebniswelt herewith is brought to a close.