The lakes of Titan

The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70 degrees north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface 'liquid methane' table.

Prevalence, diagnosis and relation to tobacco dependence of chronic obstructive pulmonary disease in a nationally representative population sample

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the fourth most common cause of death worldwide. It is caused primarily by cigarette smoking. Given its importance, it is remarkable that reliable national prevalence data are lacking for most countries. This study provides estimates of the national prevalence of COPD in England, the extent of under-detection of the disorder, and patterns of cigarette smoking, dependence, and motivation to stop smoking in those with the disease.

METHODS

Data from 8215 adults over the age of 35 who participated in the Health Survey for England were analysed. Information was obtained on self-reported and cotinine validated smoking status, cigarette dependence, motivation to stop smoking, COPD defined by spirometry using joint American Thoracic Society and European Respiratory Society criteria, and self-reports of diagnosis with respiratory disorders.

RESULTS

Spirometry-defined COPD was present in 13.3% (95% CI 12.6 to 14.0) of participants, over 80% of whom reported no respiratory diagnosis. Even among people with severe or very severe COPD by spirometric assessment, only 46.8% (95% CI 39.1 to 54.6) reported any diagnosed respiratory disease. A total of 34.9% (95% CI 32.1 to 37.8) of people with spirometry-defined COPD were smokers compared with 22.4% (95% CI 21.4 to 23.4) of those without, and smoking prevalence increased with disease severity. Smokers with spirometry-defined COPD were more cigarette dependent but had no greater desire to quit than other smokers.

CONCLUSION

COPD is common among adults in England and is predominantly undiagnosed. In smokers it is associated with higher degrees of cigarette dependence but not with a greater motivation to stop smoking.

Smoking cessation in patients with respiratory diseases: a high priority, integral component of therapy

Smoking cessation is the one of the most important ways to improve the prognosis of patients with respiratory disease. The Task Force on guidelines for smoking cessation in patients with respiratory diseases was convened to provide evidence-based recommendations on smoking cessation interventions in respiratory patients. Based on the currently available evidence and the consensus of an expert panel, the following key recommendations were made. 1) Patients with respiratory disease have a greater and more urgent need to stop smoking than the average smoker, so respiratory physicians must take a proactive and continuing role with all smokers in motivating them to stop and in providing treatment to aid smoking cessation. 2) Smoking cessation treatment should be integrated into the management of the patient's respiratory condition. 3) Therapies should include pharmacological treatment (i.e. nicotine replacement therapy, bupropion or varenicline) combined with behavioural support. 4) Respiratory physicians should receive training to ensure that they have the knowledge, attitudes and skills necessary to deliver these interventions or to refer to an appropriate specialist. 5) Although the cost of implementing these recommendations will partly be offset by a reduction in attendance for exacerbations, etc., a budget should be established to enable implementation. Research is needed to establish optimum treatment strategies specifically for respiratory patients.

Isolation of large numbers of human mesenchymal stem cells from discarded filters after bone marrow harvests: Implications for therapy

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Background: Bone Marrow (BM) is an excellent source of Mesenchymal Stem Cells (MSCs) which can be expanded and used clinically. There is a growing evidence that MSCs can promote engraftment and reduce Graft versus Host Disease (GVHD). Bone marrow harvests are passed through 850μ, 500μ and 200μ filters to trap bony spicules and clots before infusion into patients. We hypothesize that the filters would also trap a significant number of MSCs which can be useful clinically after isolation and possible expansion. Methods: Bone marrow collection kits were obtained after informed consent of the donor (n = 11). Specimens were obtained in the course of scheduled bone marrow harvests. Cells were isolated and cultured from each portion of the device. Results: An average of 1×109 total mononuclear cells was obtained from the discarded marrow collection devices. Cells isolated in this experiment conform to published data regarding MSCs. The immunophenotype was CD44+, CD73+, CD90+, CD105+, CD14−, CD34−, CD45−, HLA-DR−, negative for leukocyte lineage specific antigens and positive for Prolyl-4-Hydroxylase. The cells were morphologically consistent with published data, being bilaterally symmetrical and forming conspicuous fibroblastoid colonies which readily grew to confluence and followed differentiation pathways to both adipose osteoid tissue. Fresh cells from the kits may also contain a precursor for MSCs that is CD90− and CD73−. Sorting for this precursor population yielded colony forming units consistent with MSCs. Conclusion: This represents a novel strategy for obtaining “healthy” material for potential therapy and study.

No significant financial relationships to disclose.

Titan Radar Mapper observations from Cassini's T3 fly-by

Cassini's Titan Radar Mapper imaged the surface of Saturn's moon Titan on its February 2005 fly-by (denoted T3), collecting high-resolution synthetic-aperture radar and larger-scale radiometry and scatterometry data. These data provide the first definitive identification of impact craters on the surface of Titan, networks of fluvial channels and surficial dark streaks that may be longitudinal dunes. Here we describe this great diversity of landforms. We conclude that much of the surface thus far imaged by radar of the haze-shrouded Titan is very young, with persistent geologic activity.

Upregulation of histidine decarboxylase expression in superficial cortical nephrons during pregnancy in mice and women

Mechanisms regulating pregnancy-induced changes in renal function are incompletely understood. Few candidate genes have been identified and data suggest that alternate mechanisms remain to be elucidated. Our objective was to screen thousands of genes expressed in kidneys from mice throughout gestation to identify possible key regulators of renal function during pregnancy. Mouse complementary DNA microarrays were used to screen for differences in expression during pregnancy in C57BL/6 mice. Interesting candidate genes whose expression varied with pregnancy were further analyzed by reverse transcription-PCR and Northern blot. Expression was localized by in situ hybridization and immunohistochemistry. Follow-up immunohistochemical analyses in archival human kidney sections from the fetus, non-pregnant, and pregnant women were also performed. Histidine decarboxylase (HDC), the enzyme that synthesizes histamine, was markedly upregulated in the mouse kidney during pregnancy. HDC expression localized to proximal tubule cells of fetal and adult mice. Females showed strong expression in the juxtamedullary zone before pregnancy and upregulation in the superficial cortical zone (SCZ) by mid-gestation. Histamine colocalized with HDC. Male mice showed only low HDC expression. Similar expression patterns were observed in human kidneys. Our results show that HDC expression and histamine production are increased in the SCZ during pregnancy. If histamine acts as a vasodilator, we speculate that increasing production in the SCZ may increase renal blood flow to this zone and recruit superficial cortical nephrons during pregnancy.

The Sand Seas of Titan: Cassini RADAR Observations of Longitudinal Dunes

The most recent Cassini RADAR images of Titan show widespread regions (up to 1500 kilometers by 200 kilometers) of near-parallel radar-dark linear features that appear to be seas of longitudinal dunes similar to those seen in the Namib desert on Earth. The Ku-band (2.17-centimeter wavelength) images show approximately 100-meter ridges consistent with duneforms and reveal flow interactions with underlying hills. The distribution and orientation of the dunes support a model of fluctuating surface winds of approximately 0.5 meter per second resulting from the combination of an eastward flow with a variable tidal wind. The existence of dunes also requires geological processes that create sand-sized (100- to 300-micrometer) particulates and a lack of persistent equatorial surface liquids to act as sand traps.

Awareness of mouth cancer in Great Britain

OBJECTIVE

There are more than 2,000 new cases of mouth cancer each year in Britain. Early detection is important yet little is known about population awareness of this disease and ability to recognise early signs, particularly among high risk groups. This study aimed to address this issue.

METHODS

Data were collected by means of household survey. A total of 3,384 adults were questioned using a national probability sample. Respondents provided information on demographic characteristics, smoking status, and frequency of alcohol use. They were asked whether they had heard of mouth cancer. Their knowledge of early signs and risk factors was assessed.

RESULTS

Whereas 95.6% of respondents said they had heard of mouth cancer, their awareness of early signs was low; for example, only 33.8% recognised that white patches in the mouth were a sign. The large majority understood that smoking and chewing tobacco were risk factors (84.7% and 80.1% respectively) but only 19.4% recognised alcohol use as a risk factor. In multiple logistic regression analyses controlling for relevant demographic factors, smokers and those with more frequent alcohol consumption were less likely to recognise early signs.

CONCLUSIONS

Awareness of early signs of mouth cancer is low and lower in people who as a result of their behaviour are at higher risk. There is a need to raise awareness in those at most risk.

Levels of toxins in oral tobacco products in the UK

OBJECTIVE

This study examined the constituents of smokeless tobacco products available in the UK and compared them with products available in India, Sweden, and the USA.

METHODS

Seven UK brands of smokeless tobacco, including a tooth cleaning powder, and four international brands of smokeless tobacco were tested for a range of toxins and known carcinogens, such as tobacco specific N-nitrosamines (TSNA), as well as nicotine availability.

RESULTS

Ten of the 11 brands tested had detectable levels of tobacco specific nitrosamines, which are proven carcinogens, and levels varied 130-fold. All had detectable levels of benzo(a)pyrene, another proven carcinogen (with around 175-fold variation) and several toxic metals (with nearly 150-fold variation). Nicotine availability varied in the UK products from 0.1 mg/g to 63.2 mg/g. All the tobacco products tested are likely to be hazardous to users' health, but the data indicate that it should be possible to reduce key toxins to non-detectable levels.

CONCLUSIONS

Smokeless tobacco products should be regulated and standards set for maximum levels of toxins and carcinogens.

The role of microarray technologies in the study of soft tissue tumours

Array technologies (gene array, tissue microarray and others) are being used in a growing number of research projects involving soft tissue tumours. Gene array techniques allow for measurements of RNA expression levels or gene copy number changes for a large number of genes in a single specimen. A complementary technique, tissue microarrays, allows for the measurement of expression of a single gene in a large number of specimens. These techniques and similar ones have created a fundamentally new approach to the investigation of soft tissue tumours. This review addresses some of the advantages, problems, and solutions to those problems that come with these technologies.

Cassini Observes the Active South Pole of Enceladus

Cassini has identified a geologically active province at the south pole of Saturn's moon Enceladus. In images acquired by the Imaging Science Subsystem (ISS), this region is circumscribed by a chain of folded ridges and troughs at approximately 55 degrees S latitude. The terrain southward of this boundary is distinguished by its albedo and color contrasts, elevated temperatures, extreme geologic youth, and narrow tectonic rifts that exhibit coarse-grained ice and coincide with the hottest temperatures measured in the region. Jets of fine icy particles that supply Saturn's E ring emanate from this province, carried aloft by water vapor probably venting from subsurface reservoirs of liquid water. The shape of Enceladus suggests a possible intense heating epoch in the past by capture into a 1:4 secondary spin/orbit resonance.

Enceladus' Water Vapor Plume

The Cassini spacecraft flew close to Saturn's small moon Enceladus three times in 2005. Cassini's UltraViolet Imaging Spectrograph observed stellar occultations on two flybys and confirmed the existence, composition, and regionally confined nature of a water vapor plume in the south polar region of Enceladus. This plume provides an adequate amount of water to resupply losses from Saturn's E ring and to be the dominant source of the neutral OH and atomic oxygen that fill the Saturnian system.

Rain, winds and haze during the Huygens probe's descent to Titan's surface

The irreversible conversion of methane into higher hydrocarbons in Titan's stratosphere implies a surface or subsurface methane reservoir. Recent measurements from the cameras aboard the Cassini orbiter fail to see a global reservoir, but the methane and smog in Titan's atmosphere impedes the search for hydrocarbons on the surface. Here we report spectra and high-resolution images obtained by the Huygens Probe Descent Imager/Spectral Radiometer instrument in Titan's atmosphere. Although these images do not show liquid hydrocarbon pools on the surface, they do reveal the traces of once flowing liquid. Surprisingly like Earth, the brighter highland regions show complex systems draining into flat, dark lowlands. Images taken after landing are of a dry riverbed. The infrared reflectance spectrum measured for the surface is unlike any other in the Solar System; there is a red slope in the optical range that is consistent with an organic material such as tholins, and absorption from water ice is seen. However, a blue slope in the near-infrared suggests another, unknown constituent. The number density of haze particles increases by a factor of just a few from an altitude of 150 km to the surface, with no clear space below the tropopause. The methane relative humidity near the surface is 50 per cent.

Complications of diagnostic cardiac catheterisation: results from a confidential inquiry into cardiac catheter complications

OBJECTIVES

To estimate the frequency and nature of complications in patients undergoing diagnostic cardiac catheterisation and to assess time trends in complications since the introduction of a voluntary cooperative audit.

METHODS

Cardiac centres undertaking diagnostic cardiac catheterisation in England and Wales during the 10 years 1990-9 were invited to join the study. Each participating centre reported numbers of patients catheterised each month and details of complications and deaths as they occurred. Complication rates were calculated for the main diagnostic procedures and for each participating hospital and time trends in complications were examined.

RESULTS

41 cardiac centres contributed. 211 645 diagnostic procedures in adults and 7582 paediatric procedures were registered. The majority (87%) of diagnostic catheter studies in adults were left heart studies with coronary arteriography. The overall complication rate for adult procedures was 7.4/1000, with mortality at 0.7/1000; for paediatric procedures the complication rate was similar but mortality rather higher. Complication rates varied between centres but there was little association with caseload. Time trends across the decade showed both complication and mortality decreasing; from 9.5 to 5.8/1000 and from 1.4 to 0.4/1000, respectively.

CONCLUSION

Complication rates of diagnostic catheterisation are low but neither negligible nor irreducible. While voluntary audit of cardiac catheter complications is useful and inexpensive, there is a clear need to establish a formal reporting system in all cardiac catheter laboratories, with clear definitions of reportable complications.

Impact of UK policy initiatives on use of medicines to aid smoking cessation

CONTEXT

Increasing the use of effective smoking cessation aids could in principle have a substantial public health impact. The UK government has undertaken several major policy initiatives to try to increase usage of smoking cessation medicines. It is important to evaluate what effect, if any, these have had to inform future policy in the UK and internationally.

OBJECTIVE

This study used sales data to examine the impact of government initiatives to increase access to smoking cessation medicines.

DESIGN

Information about prescription and non-prescription sales (1999-2002) was obtained. Estimates of utilisation were compared with findings from the Office of National Statistics (ONS) omnibus surveys. The effects of policy initiatives (making the medicines reimbursable and making them available on general sale outside pharmacies) were assessed by means of time series analysis. In addition a new nicotine replacement therapy (NRT) product (a nicotine lozenge) was launched and the effect of this on total utilisation was assessed.

RESULTS

Making bupropion, and subsequently nicotine replacement therapy (NRT), reimbursable had a major impact in medication usage; the estimated increase in each case was more than 80 000 "treatment weeks" purchased per month. In addition, introduction of a nicotine lozenge increased total utilisation and did not detract from usage of other medicines. According to both the sales and the survey data, the proportion of smokers using medicines to aid smoking cessation more than doubled from 8-9% in 1999 to 17% in 2002. The ONS surveys showed no increase in the proportions of smokers making quit attempts and so the effects were solely on the proportions of quit attempts that were aided by medication.

CONCLUSIONS

In the UK, making smoking cessation medicines reimbursable led to a large increase in utilisation. While the effect on smoking prevalence would be too small to be detected in national surveys it could have a substantial public health impact.

Cassini Radar Views the Surface of Titan

The Cassini Titan Radar Mapper imaged about 1% of Titan's surface at a resolution of approximately 0.5 kilometer, and larger areas of the globe in lower resolution modes. The images reveal a complex surface, with areas of low relief and a variety of geologic features suggestive of dome-like volcanic constructs, flows, and sinuous channels. The surface appears to be young, with few impact craters. Scattering and dielectric properties are consistent with porous ice or organics. Dark patches in the radar images show high brightness temperatures and high emissivity and are consistent with frozen hydrocarbons.

General practitioners' views on and referral to NHS smoking cessation services

OBJECTIVES

Increasing the rate of smoking cessation remains a major public health goal. To help achieve this in the UK, National Health Service (NHS) smoking cessation services have been established to provide treatment for smokers wanting help with stopping. Referrals from general practitioners (GPs) are crucial to the success of these clinics. This study aimed to assess English GPs' self-reported interactions with, and attitudes towards, their local smoking cessation services.

STUDY DESIGN

Postal survey assessing the attitudes of GPs in England towards, and formal interactions with, NHS smoking cessation services.

METHODS

A questionnaire was posted to a random sample of 544 GPs in England (response rate 63%). GPs' self-reported interactions with smoking cessation services and their attitudes towards these clinics were assessed. GPs were also asked what factors determined whether they prescribed nicotine-replacement therapy (NRT) and Buproprion (Zyban), and what was the extent and nature of their smoking cessation interventions with their patients.

RESULTS

Most GPs (94%) reported that they were aware of the specialist smoking cessation service in their area. Seventy percent of GPs supported the continuation of current funding for specialist smoking cessation services. Seventy percent reported that they referred patients to these services, and 55% had staff within their practices trained as community smoking cessation advisors. Most GPs (79%) reported 'clinical need' as a determinant of whether they prescribed NRT/Zyban, and a few GPs cited 'budgetary constraints' as a factor (15%). Ninety-eight percent of GPs reported that they record smoking status when new patients join their practice, and they advise smokers to stop 'at least every now and then'.

CONCLUSIONS

GPs support the existence and continuation of specialist smoking cessation services, and most reported that they refer patients to them. Virtually every GP reported that they record smoking status when new patients join their practice, and they advise smokers to stop 'at least every now and then'.

Cassini Imaging Science: Initial Results on Phoebe and Iapetus

The Cassini Imaging Science Subsystem acquired high-resolution imaging data on the outer Saturnian moon, Phoebe, during Cassini's close flyby on 11 June 2004 and on Iapetus during a flyby on 31 December 2004. Phoebe has a heavily cratered and ancient surface, shows evidence of ice near the surface, has distinct layering of different materials, and has a mean density that is indicative of an ice-rock mixture. Iapetus's dark leading side (Cassini Regio) is ancient, heavily cratered terrain bisected by an equatorial ridge system that reaches 20 kilometers relief. Local albedo variations within and bordering Cassini Regio suggest mass wasting of ballistically deposited material, the origin of which remains unknown.

Cassini Imaging Science: Initial Results on Saturn's Atmosphere

The Cassini Imaging Science Subsystem (ISS) began observing Saturn in early February 2004. From analysis of cloud motions through early October 2004, we report vertical wind shear in Saturn's equatorial jet and a maximum wind speed of approximately 375 meters per second, a value that differs from both Hubble Space Telescope and Voyager values. We also report a particularly active narrow southern mid-latitude region in which dark ovals are observed both to merge with each other and to arise from the eruptions of large, bright storms. Bright storm eruptions are correlated with Saturn's electrostatic discharges, which are thought to originate from lightning.

Cassini Imaging Science: Initial Results on Saturn's Rings and Small Satellites

Images acquired of Saturn's rings and small moons by the Cassini Imaging Science Subsystem (ISS) during the first 9 months of Cassini operations at Saturn have produced many new findings. These include new saturnian moons; refined orbits of new and previously known moons; narrow diffuse rings in the F-ring region and embedded in gaps within the main rings; exceptionally fine-scale ring structure in moderate- to high-optical depth regions; new estimates for the masses of ring-region moons, as well as ring particle properties in the Cassini division, derived from the analysis of linear density waves; ring particle albedos in select ring regions; and never-before-seen phenomena within the rings.