On the alignment of debris disks and their host stars' rotation axis -implications for spin-orbit misalignment in exoplanetary systems

It has been widely thought that measuring the misalignment angle between the orbital plane of a transiting exoplanet and the spin of its host star was a good discriminator between different migration processes for hot-Jupiters. Specifically, well-aligned hot-Jupiter systems (as measured by the Rossiter-McLaughlin effect) were thought to have formed via migration through interaction with a viscous disc, while misaligned systems were thought to have undergone a more violent dynamical history. These conclusions were based on the assumption that the planet-forming disc was well-aligned with the host star. Recent work by Lai et al. has challenged this assumption, and proposes that the star-disc interaction in the pre-main sequence phase can exert a torque on the star and change its rotation axis angle. We have estimated the stellar rotation axis of a sample of stars which host spatially resolved debris disks. Comparison of our derived stellar rotation axis inclination angles with the geometrically measured debris-disk inclinations shows no evidence for a misalignment between the two.

Rotation periods of exoplanet host stars

The stellar rotation periods of 10 exoplanet host stars have been determined using newly analysed CaII H&K flux records from the Mount Wilson Observatory and Strömgren b, y photometric measurements from Tennessee State University's automatic photometric telescopes at the Fairborn Observatory. Five of the rotation periods have not previously been reported, with that of HD 130322 very strongly detected at Prot = 26.1 +/- 3.5 d. The rotation periods of five other stars have been updated using new data. We use the rotation periods to derive the line-of-sight inclinations of the stellar rotation axes, which may be used to probe theories of planet formation and evolution when combined with the planetary orbital inclination found from other methods. Finally, we estimate the masses of 14 exoplanets under the assumption that the stellar rotation axis is aligned with the orbital axis. We calculate the mass of HD 92788 b (28 MJ) to be within the low-mass brown dwarf regime and suggest that this object warrants further investigation to confirm its true nature.

Are there clinical features of a sensitized cough reflex?

Cough reflex hypersensitization is a key feature in patients with troublesome cough. The clinical consequence of this hypersensitive state is typified by bouts of coughing often triggered by low threshold stimuli encountered by the patient during normal daily activities including exposure to aerosols, scents and odours, a change in air temperature and when talking or laughing. These features are often perceived by cough patients to be the most disruptive aspect of their condition and undoubtedly contribute to impaired quality of life. Patients with troublesome cough may describe a range of additional symptoms and sensations including an 'urge to cough' or the feeling of an 'itch' at the back of the throat, or a choking sensation and occasionally chest pain or breathlessness. It is uncertain if these features arise due to the processes responsible for cough reflex sensitization or as a direct consequence of the underlying cough aetiology. In an attempt to understand the clinical features of a sensitized cough reflex, the spectrum of symptoms typically described by cough patients will be reviewed and possible underlying mechanisms considered. Since an intact cough reflex is crucial to airway protection, anti-tussive treatment that attenuates the hypersensitive cough state rather than abolishing the cough reflex completely would be preferable. Identifying such agents remains a clinical, scientific and pharmacological challenge. (c) 2008 Elsevier Ltd. All rights reserved.

A Family of Helminth Molecules that Modulate Innate Cell Responses via Molecular Mimicry of Host Antimicrobial Peptides

Over the last decade a significant number of studies have highlighted the central role of host antimicrobial (or defence) peptides in modulating the response of innate immune cells to pathogen-associated ligands. In humans, the most widely studied antimicrobial peptide is LL-37, a 37-residue peptide containing an amphipathic helix that is released via proteolytic cleavage of the precursor protein CAP18. Owing to its ability to protect against lethal endotoxaemia and clinically-relevant bacterial infections, LL-37 and its derivatives are seen as attractive candidates for anti-sepsis therapies. We have identified a novel family of molecules secreted by parasitic helminths (helminth defence molecules; HDMs) that exhibit similar biochemical and functional characteristics to human defence peptides, particularly CAP18. The HDM secreted by Fasciola hepatica (FhHDM-1) adopts a predominantly alpha-helical structure in solution. Processing of FhHDM-1 by F. hepatica cathepsin L1 releases a 34-residue C-terminal fragment containing a conserved amphipathic helix. This is analogous to the proteolytic processing of CAP18 to release LL-37, which modulates innate cell activation by classical toll-like receptor (TLR) ligands such as lipopolysaccharide (LPS). We show that full-length recombinant FhHDM-1 and a peptide analogue of the amphipathic C-terminus bind directly to LPS in a concentration-dependent manner, reducing its interaction with both LPS-binding protein (LBP) and the surface of macrophages. Furthermore, FhHDM-1 and the amphipathic C-terminal peptide protect mice against LPS-induced inflammation by significantly reducing the release of inflammatory mediators from macrophages. We propose that HDMs, by mimicking the function of host defence peptides, represent a novel family of innate cell modulators with therapeutic potential in anti-sepsis treatments and prevention of inflammation.

Fasciola hepatica: Comparative effects of host resistance and parasite intra-specific interactions on size and reproductive histology in flukes from rats infected with isolates differing in triclabendazole sensitivity

The efficacies of putative fasciolicides and vaccines against Fasciola hepatica are frequently monitored in clinical and field trials by determination of fluke egg output in host faeces and by worm counts in the host liver at autopsy. Less often used are parameters based on fluke size and histology, yet these can provide important indications of specific effects on the development of particular germ-line or somatic tissues, especially in relation to the timing and profligacy of egg production. In this study. F. hepatica metacercariae of two distinct isolates, the triclabendazole (TCBZ)-sensitive Cullompton isolate and the TCBZ-resistant Oberon isolate, were administered to rats as single-isolate or mixed-isolate infections. At autopsy 16 weeks later individual adult flukes were counted, measured and the reproductive organs were examined histologically. The degree of development of the testis tubules in each fluke was represented by a numerical score, based on the proportion of the histological section profiles occupied by testis tissue. The level of anti-F. hepatica antibody in the serum of each rat was determined by ELISA. It was found that Cullompton flukes were significantly larger than Oberon flukes, and that significantly more Cullompton metacercariae developed to adults than Oberon metacercariae. The Cullompton flukes showed histological evidence of aspermy and spermatogenic arrest, which was reflected in quantitatively reduced testicular development, as compared with the Oberon isolate. In Cullompton flukes, parthenogenetic egg development is implied. The size of Cullompton and Oberon flukes was significantly related to the number of adult flukes recovered, to the number of metacercariae administered, and to the percentage success of infection. The testis development score in both isolates was significantly related to the number of adult flukes recovered but not to the number of metacercariae administered, or to the percentage success of infection. Fluke size was positively related to testis score for both isolates, and a significant negative relationship was found between percentage success of infection and metacercarial dose. The results are interpreted in terms of differing interactions between various numbers of young flukes and host immunity during invasion of and migration in the hepatic parenchyma, and of fluke intra-specific (possibly pheromonal) stimulatory effects in the final stages of development, within the host bile ducts. No significant relationships were found between host antibody levels and fluke size or testis score. False positive serological reactions were found in some rats that had been infected, but found to harbour no flukes at autopsy. Clearly the act of eliminating the flukes involved generation of an immune response. (C) 2011 Elsevier B.V. All rights reserved.