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The Pluto system was recently explored by NASA's New Horizons spacecraft, making closest approach on 14 July 2015. Pluto's surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto's atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto's diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto's large moon Charon displays tectonics and evidence for a heterogeneous crustal composition; its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected., (Copyright © 2015, American Association for the Advancement of Science.)

Objectives: We aimed to determine the prevalence of hydronephrosis in patients who underwent renal sonography for new-onset acute kidney injury (AKI) and to identify clinical factors predictive of hydronephrosis. In patients with hydronephrosis, we sought to investigate how routine renal sonography affects patient treatment, including performance of interventional procedures., Methods: A retrospective chart review identified 274 adults with AKI who underwent renal sonography at an urban teaching hospital from January through July 2011. The prevalence of hydronephrosis was determined. Electronic medical records were reviewed for comorbidities, including risk factors for hydronephrosis such as a pelvic mass, prior renal or pelvic surgery, and neurogenic bladder, and for subsequent interventions and outcomes., Results: Sonography showed hydronephrosis in 28 patients (10%); 5 (18%) had subsequent interventions. In a multivariable logistic regression model with the outcome being hydronephrosis, all considered risk factors (pelvic mass, prior renal or pelvic surgery, and neurogenic bladder) were significantly associated with hydronephrosis (odds ratio, 6.4; 95% confidence interval, 2.7-15.4; P < .001) when adjusting for age and diabetes mellitus. Diabetes had a negative predictive value for hydronephrosis. No diabetic patients younger than 85 years and without clinical risk factors had hydronephrosis., Conclusions: Hydronephrosis is infrequently seen on sonograms in hospitalized patients with AKI who lack risk factors for urinary tract obstruction. Deferral of sonography pending a trial of medical treatment is safe and will reduce medical costs. Adoption of clinical guidelines to assess patients' risk levels for hydronephrosis is critical to avoid unnecessary imaging., (© 2015 by the American Institute of Ultrasound in Medicine.)

Objective: An exploratory study to investigate general practitioners' (GPs') views and experiences of consulting with young people (aged 12-19 years) presenting with emotional distress in general practice., Design: A qualitative study using grounded theory and situational analysis. Empirical data were generated through in-depth interviews based on a topic guide developed from the literature, and augmented with a series of situational maps. Continuous field notes and theoretical memos were recorded during data collection and analysis. The data were analysed using the constant comparative method of grounded theory. There were three levels of analysis. The first level developed the open codes and is presented here., Setting: 18 general practices located in the north east of England. The practices recruited included rural, urban and mixed populations of patients who were predominantly living in socioeconomically disadvantaged communities., Participants: 19 GPs (10 women) aged between 29 and 59 years participated. The modal age range was 40-49 years. Theoretical sampling was used to guide recruitment and continued until theoretical saturation was reached., Results: The overarching finding was that anxiety about practice dominated clinical consultations involving young people presenting with emotional distress. GPs responded differently to anxiety and to related uncertainties about professional practice, independent of GP age or gender. Anxiety occurred in the consultation, at an external level, across disciplinary boundaries, in relation to communication with young people and secondary to the complexity of presentations., Conclusions: Adolescent emotional distress presents professional challenges to GPs who feel ill-equipped and inadequately prepared to address early need. Medical education needs to prepare doctors better. More research is needed to look at what factors facilitate or prohibit greater GP engagement with emotionally distressed young people.

Background: Australia and England show high rates of psychological distress and mental health problems in young people. Both are high-income countries and have stated their intention to improve the delivery of health care to young people in primary care settings. Australia has an international reputation for improving care through innovative services and educational initiatives. England has taken a different direction and has concentrated more on developing policy and making recommendations to improve access for young people., Aim: To describe a Churchill Fellowship visit to Australia to observe initiatives in primary care based youth-friendly mental health care and to reflect upon the observations, comparing and contrasting with the English model., Methods: The observations and reflections presented draw on field notes from site visits and meeting with key players, accessing web resources and referring to the literature, both grey and published., Findings: Australia offers plurality in health care delivery and innovative responses to addressing youth mental health. There are two key approaches. The first is the development of services specializing in youth mental health. The second approach is to build capacity of existing primary care services to recognize the particular bio-psychosocial needs of adolescents (and their families). In contrast, England has tended to focus primarily on policy development and improving youth access., Conclusions: The paper draws attention to a number of political, clinical and educational developments in both Australia and England. Both countries demonstrate different strategies in response to the high levels of psychological distress in young people. Learning from colleagues in other settings can inform our own practice. Ultimately responding to young people's mental health needs is best served by youth-friendly policy which prepares clinicians for effective practice, informed by applied research and supported by adequate resources. Investment in young people's health must be a priority for us all.

Background General practitioners (GPs) play a key role in assessing and managing adult mental health problems, but this input is not seen in their management of child and adolescent mental health. Mental health problems in 5-19-year-olds are common, yet detection rates in primary care are low. The symptoms of most adult diagnoses of mental health problems are present by mid-adolescence, yet the typical time from onset to diagnosis is 5-15 years. The role of general practice in this area has been underexplored. Aim This pilot study explores the potential of GPs to respond to common mental health problems in children and adolescents. Design Children and young people who would have ordinarily been referred to Child and Adolescent Mental Health Services (CAMHS) were seen in a GP setting. In a UK general practice surgery serving a disadvantaged population. Method Children and young people were seen for an initial biopsychosocial assessment and formulation of the presenting concerns. GP-based interventions were offered as appropriate or referred to CAMHS. Results Data from the first 50 children (2-19 years) are presented. Twenty younger children (10 years and under) and 30 older children (11 years and above) were seen. Eighteen referrals were made to CAMHS. GP interventions included watchful waiting, brief behavioural interventions, non-directive counselling, brief cognitive- behavioural therapy (CBT) and liaison with colleagues in education, CAMHS and the voluntary sector. Conclusion This clinical pilot demonstrates that with adequate time, access to supervision and practice support, children and young people experiencing emotional and behavioural problems associated with common mental health issues can be helped in primary care.

Conducting polymers constitute a class of materials for which electrochemical and electron transport properties are a function not only of their chemical identity but also of their complex morphology. In this paper, we investigate and compare the frequency dependence behavior of the impedance of poly(3,4-ethylenedioxythiophene), or PEDOT, and that of poly(3,4-ethylenedioxypyrrole), or PEDOP, which are doped with a series of polyatomic anions during electrodeposition. We also contrast the behavior of PEDOT on Pt|Au, Pt, glassy carbon, and gold. Initial results for polycarbazole, PCz, electrodes are, in addition, included. Deposition parameters were adjusted to produce morphologically similar films for PEDOT, PEDOP, and PCz. In doing so, we have been successful in producing frequency-independent impedance behavior similar to that previously reported for PEDOT on Pt|Au. Although the impedance behavior of these polymers appears to be primarily determined by morphological features, the impact of counterion identity (beyond ionic charge transport) is also discussed. These studies suggest that choice of polymer/dopant combination and electrodeposition parameters can be manipulated to tune the impedance characteristics of electrodes, thereby optimizing them for capacitive or faradaic charge injection, or some combination of the two., (© 2012 American Chemical Society)

In May 2010, Grand Challenges Canada (GCC) was launched with the mandate to identify global challenges in health that could be supported through the Government of Canada's Development Innovations Fund (DIF: $225 million over five years). The GCC offers a potentially excellent mechanism for taking Canada's participation in global health challenges "to a higher level". Recent GCC announcements raise new questions about the emphasis being placed on technological discovery or "catalytic" research. Missing so far are opportunities that the Fund could offer in order to support innovative research addressing i) health systems strengthening, ii) more effective delivery of existing interventions, and iii) policies and programs that address broader social determinants of health. The Canadian Grand Challenges announced to date risk pushing to the sidelines good translational and implementation science and early career-stage scientists addressing important social, environmental and political conditions that affect disease prevalence, progress and treatment; and the many unresolved challenges faced in bringing to scale proven interventions within resource-constrained health systems. We wish to register our concern at the apparent prioritization of biotechnical innovation research and the subordination of the social, environmental, economic and political context in which human health is either protected or eroded.

Orthotopic liver transplantation is an important treatment option for patients with end-stage liver disease. Advances in surgical technique, along with improvements in organ preservation and immunosuppression have improved patient outcomes. Post-operative complications, however, can limit this success. Ultrasound is the primary imaging modality for evaluation of hepatic transplants, providing real-time information about vascular flow in the graft. Graft vascular complications are not uncommon, and their prompt recognition is crucial to allow for timely graft salvage. A multimodality approach including CT angiography, MRI, or conventional angiography may be necessary in cases of complex transplant vascular anatomy or when sonography and Doppler are inconclusive to diagnose the etiologies of these complications. The purpose of this article is to familiarize radiologists with the normal post-transplant vascular anatomy and the imaging appearances of the major vascular complications that may occur within the hepatic artery, portal vein, and venous outflow tract, with an emphasis on ultrasound.

Although education about culture, race and ethnicity has increasingly been viewed as an important addition to the medical undergraduate curriculum, internationally the evidence of its effectiveness is mixed. Research to date fails to show why. We chose to explore how contrasting approaches to learning about cultural diversity impacted on medical students. The views of second year students towards teaching about cultural diversity at two UK medical schools, with differently structured curricula, were explored using a series of focus groups (7). The findings, using a methodology based on a combination of grounded theory and thematic analysis identified two potentially competing views espoused by the students at both sites. First, they claimed that although cultural diversity was important, their medical schools marginalised and failed to adequately support effective teaching. Second, in contrast, they claimed that the medical school was an 'inappropriate' setting for successful teaching about cultural diversity. Students did not consider the subject matter to be of central relevance to biomedicine. They felt it should be learnt experientially in the workplace and socially among peers. These narratives represent two potentially conflicting standpoints, which might be understood through the sociological concept of 'habitus', where students conform to the institution's dominant values in order to succeed. The tensions identified in this study cannot be ignored if effective learning about race, ethnicity and culture is to be achieved. Early introduction to understanding the delivery of health care to diverse populations is needed. This should be accompanied by more open collaborative debate between tutors and students on the issues raised.

This discussion paper, written by a UK general practitioner and graduate student of anthropology, explores the uncomfortable relationship between institutionalised inequalities of wealth and opportunities, and emotional health, in a disadvantaged community in the north-east of England. The author begins by locating the thesis in the corpus of anthropological literature which acknowledges human suffering and refuses to adopt a position of cultural relativism. The complex and elusive phenomenon of structural violence is unpacked, followed by a description of the setting and the author's methodology. Clinical observations are presented as contextualised narratives located around three themes: alcohol misuse; gendered violence; and inter-generational violence. The vignettes portray how the consequences of institutionalised inequalities are manifest in the embodied and emotional lives of many who live in economically marginalised communities. The author concludes with a discussion of the dilemma at the heart of a morally engaged practitioner's clinical practice as one who eschews the dominant ideology of individual responsibility for health and recognises that agency is compromised by structural violence.

Health determinants and how they are distributed have an important impact on health systems around the world. Nurses can play a significant role in mediating the effects of many of these determinants both inside the health care system and outside. Yet the areas that have the greatest health inequities and heaviest disease burdens have the fewest health workers. A number of efforts are underway to understand and manage health care worker migration. Intersectoral collaboration is key, as are other factors necessary to build strong health systems, including research for development, capacity-building, integrated health systems, evidence-based decision-making, a strong and vibrant civil society and accountability and transparency in the public and private sectors.

The Roanoke logperch (Percina rex Jordan and Evermann), an endangered fish, occurs in only six watersheds in the Roanoke and Chowan river drainages of Virginia, USA. The species' population genetic structure is poorly known. We developed 16 microsatellite markers that were reliably scorable and polymorphic P. rex. Markers were also screened in seven other darter species of the genus Percina. Most markers exhibited successful amplification and polymorphism in several species. These markers may therefore prove useful for population genetic studies in other darters, a diverse but highly imperiled group., (© 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd.)

Relationships between environmental variability and movement are poorly understood, due to both their complexity and the limited ecological scope of most movement studies. We studied movements of fantail (Etheostoma flabellare), riverweed (E. podostemone), and Roanoke darters (Percina roanoka) through two stream systems during two summers. We then related movement to variability in measured habitat attributes using logistic regression and exploratory data plots. We indexed habitat conditions at both microhabitat (i.e., patches of uniform depth, velocity, and substrate) and mesohabitat (i.e., riffle and pool channel units) spatial scales, and determined how local habitat conditions were affected by landscape spatial (i.e., longitudinal position, land use) and temporal contexts. Most spatial variability in habitat conditions and fish movement was unexplained by a site's location on the landscape. Exceptions were microhabitat diversity, which was greater in the less-disturbed watershed, and riffle isolation and predator density in pools, which were greater at more-downstream sites. Habitat conditions and movement also exhibited only minor temporal variability, but the relative influences of habitat attributes on movement were quite variable over time. During the first year, movements of fantail and riverweed darters were triggered predominantly by loss of shallow microhabitats; whereas, during the second year, microhabitat diversity was more strongly related (though in opposite directions) to movement of these two species. Roanoke darters did not move in response to microhabitat-scale variables, presumably because of the species' preference for deeper microhabitats that changed little over time. Conversely, movement of all species appeared to be constrained by riffle isolation and predator density in pools, two mesohabitat-scale attributes. Relationships between environmental variability and movement depended on both the spatiotemporal scale of consideration and the ecology of the species. Future studies that integrate across scales, taxa, and life-histories are likely to provide greater insight into movement ecology than will traditional, single-season, single-species approaches.

Objective: The purpose of this study was to define the sonographic characteristics of the vaginal cuff and cervical remnant after hysterectomy and to establish normal measurements of each after each type of surgery., Materials and Methods: One hundred twenty-one women who had undergone hysterectomy (mean age, 51 years; range, 31-80 years) were studied using transabdominal or transvaginal sonography. Seventy-six patients were acquired retrospectively and 45 prospectively. Hysterectomy types included abdominal, 52% (63/121); supracervical, 17% (20/121); vaginal, 17% (20/121); and unknown, 15% (18/121). Two reviewers, who were blinded to clinical information, evaluated each cuff or remnant in consensus. Transabdominal anteroposterior, transvaginal anteroposterior, and transvaginal length measurements before and after transducer compression, and amount of color Doppler flow as shown by percentage of color pixels (n = 36 patients) were correlated with hysterectomy type and patient age., Results: Supracervical cuffs were larger (p < 0.01) than abdominal and vaginal hysterectomy cuffs (transabdominal sonography anteroposterior, 2.8 vs 1.5 and 1.6 cm; transvaginal sonography anteroposterior, 3.3 vs 1.8 and 1.7 cm; and transvaginal length, 3.0 vs 2.1 and 1.9 cm). Anteroposterior measurements, but not length, decreased significantly with advancing age. Transvaginal length decreased with compression (mean, 0.84 cm; p < 0.0001). Color Doppler flow scores (minimum, 56% [20/36]; mild, 28% [10/36]; moderate, 14% [5/36]; and absent, 3% [1/36]) did not vary with age, time since surgery, or type of surgery., Conclusion: The remnant is larger in every dimension after supracervical hysterectomy compared with both abdominal and vaginal hysterectomy and commonly shows some color Doppler flow.

There has been a lot of research on marketing as an offensive tactic-how it can help companies successfully launch new products, enter new markets, or gain share with existing products in their current markets. But for nearly every new product launch, market entrant, or industry upstart grabbing market share, there is an incumbent that must defend its position. And there has been little research on how these defenders can use marketing to preemptively respond to new or anticipated threats. John H. Roberts outlines four basic types of defensive marketing strategies: positive, inertial, parity, and retarding. With the first two, you establish and communicate your points of superiority relative to the new entrant; with the second two, you establish and communicate strategic points of comparability with your rival. Before choosing a strategy, you need to assess the weapons you have available to protect your market position-your brand identity, the products and services that support that identity, and your means of communicating it. Then assess your customers' value to you and their vulnerability to being poached by rivals. The author explains how Australian telecommunications company Telstra, facing deregulation, used a combination of the four strategies (plus the author's customer response model) to fend off market newcomer Optus. Telstra was prepared, for instance, to reach deep into its pockets and engage in a price war. But the customer response model indicated that a parity strategy-in which Telstra would offer lower rates on some routes and at certain times of day, even though its prices, on average, were higher than its rival's-was more likely to prevent consumers from switching. Ultimately, Telstra was able to retain several points of market share it otherwise would have lost. The strategies described here, though specific to Telstra's situation, offer lessons for any company facing new and potentially damaging competition.

BACKGROUND: Global health research is essential for development. A major issue is the inequitable distribution of research efforts and funds directed towards populations suffering the world's greatest health problems. This imbalance is fostering major attempts at redirecting research to the health problems of low and middle income countries. Following the creation of the Coalition for Global Health Research - Canada (CGHRC) in 2001, the Canadian Society for International Health (CSIH) decided to review the role of non-governmental organizations (NGOs) in global health research. This paper highlights some of the prevalent thinking and is intended to encourage new thinking on how NGOs can further this role. APPROACH: This paper was prepared by members of the Research Committee of the CSIH, with input from other members of the Society. Persons working in various international NGOs participated in individual interviews or group discussions on their involvement in different types of research activities. Case studies illustrate the roles of NGOs in global health research, their perceived strengths and weaknesses, and the constraints and opportunities to build capacity and develop partnerships for research. HIGHLIGHTS: NGOs are contributing at all stages of the research cycle, fostering the relevance and effectiveness of the research, priority setting, and knowledge translation to action. They have a key role in stewardship (promoting and advocating for relevant global health research), resource mobilization for research, the generation, utilization and management of knowledge, and capacity development. Yet, typically, the involvement of NGOs in research is downstream from knowledge production and it usually takes the form of a partnership with universities or dedicated research agencies. CONCLUSION: There is a need to more effectively include NGOs in all aspects of health research in order to maximize the potential benefits of research. NGOs, moreover, can and should play an instrumental role in coalitions for global health research, such as the CGHRC. With a renewed sense of purpose and a common goal, NGOs and their partners intend to make strong and lasting inroads into reducing the disease burden of the world's most affected populations through effective research action.

Objective: Pregnant patients without a sonographically visible intrauterine pregnancy and with a thick-walled cystic adnexal structure present a dilemma. This study compared the utility of various sonographic features in differentiating between the tubal ring of ectopic pregnancy and the corpus luteum., Methods: Retrospective review of first-trimester transvaginal sonograms revealed a cystic adnexal structure in 79 women. Each structure was evaluated for 6 specific sonographic characteristics: echogenicity of its wall compared with that of the ovary and endometrium, wall thickness in 2 planes, color Doppler flow distribution and percentage of wall circumference, and internal texture., Results: Forty-one (52%) of the 79 women had ectopic pregnancies, and 38 (48%) had corpora lutea. Eleven (32%) of 35 ectopic walls were more echogenic than the endometrium, compared with none of the corpora lutea. A cyst wall less echogenic than the endometrium was more likely in corpora lutea (84% versus 31%; P < .0001). More than twice as many ectopic rinds were more echogenic than ovarian tissue compared with corpora lutea (76% versus 34%; P < .0001). The only predictive internal texture feature was a clear pattern, which was more common in the corpora lutea (P < .01, Fisher exact test). There was no significant difference in mural flow distribution or extent between the 2 groups., Conclusions: Ancillary sonographic signs to distinguish between an ectopic pregnancy and a corpus luteum include decreased wall echogenicity compared with the endometrium and an anechoic texture, which suggests a corpus luteum.

Objective: Half of all preterm births occur in women without clinical risk factors. Our goal was to assess fetal fibronectin assay, Bishop score, and cervical ultrasonography as screening tests to predict which low-risk pregnancies will end in preterm birth., Study Design: We performed a secondary analysis of data collected at 22 to 24 weeks' gestation from low-risk subjects enrolled in the Preterm Prediction Study, an observational study of risk factors for preterm birth conducted by the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Analysis was limited to primigravid women and to women who did not have a history of preterm birth or spontaneous pregnancy loss at <20 weeks' gestation. Bishop score (> or =4), fetal fibronectin level (> or =50 ng/mL), and cervical length (< or =25 mm) at 24 weeks' gestation were evaluated alone and in sequence as tests to predict spontaneous delivery before 35 weeks' gestation., Results: Of the 2929 subjects enrolled in the original study, 2197 (1207 primigravid women and 900 low-risk multiparous women) met criteria for this analysis. There were 64 spontaneous births before 35 weeks' gestation (3.04%). All three tests were significantly related to birth before 35 weeks' gestation (high Bishop score: relative risk, 3.6; 95% confidence interval, 2.1-6.3; fetal fibronectin detection: relative risk, 8.2; 95% confidence interval, 4.8-13.9; short cervical length: relative risk, 6.9; 95% confidence interval, 4.3-11.1). However, the sensitivities of the tests alone were low (23.4% for high Bishop score, 23.4% for fetal fibronectin detection, and 39.1% for short cervix), as were the sensitivities for Bishop score followed by cervical ultrasonography (14.1%) and fetal fibronectin assay followed by cervical scan (15.6%)., Conclusion: In the setting of low-risk pregnancy, fetal fibronectin assay and cervical ultrasonography have low sensitivity for preterm birth before 35 weeks' gestation. Sequential screening with Bishop score or fetal fibronectin assay followed by cervical ultrasonography further decreased sensitivity to only 15% among low-risk women.

The process of technology assessment is evolving. The process of policy development for technology is the least understood in the cycle of technology assessment. The process of policy development, which should involve extensive consultation and a broad-based research and evaluation program, is often fraught with difficulties and can cause further analysis or the assessment process to come grinding to a halt. This article reviews some social, political, and ethical issues and the role of civil society in influencing the technology assessment process for new reproductive technologies in Canada. It is written from the perspective of one of the Deputy Directors of Research and Evaluation for the Royal Commission on New Reproductive Technologies and highlights the strengths and difficulties of technology assessment when civil society and technology assessment come face to face. A brief update by a policy analyst in Health Canada on the current situation of legislation on new reproductive technologies has been provided and is included at the end of this article.

This report describes the diagnostic workup of a case of a pseudoaneurysm of the heart resulting from Staphylococcal pericarditis and/or abscesses of the myocardium. The pericardial effusion and myocardial abscesses were detected on 2D echocardiography and computed tomography. The resulting pseudoaneurysm could be demonstrated on magnetic resonance imaging and color Doppler ultrasound, and confirmed by left ventriculography. Color-encoded Doppler ultrasound alone would have provided the definitive diagnosis of the aneurysm.

From a group of industrial workers who had a noise-induced hearing loss of at least 30 dB at 4000 Hz 62 were randomly selected after stratification. Controls matched for age and duration of employment were also selected. Resting blood pressures were measured and audiometry was repeated. The findings are presented by age group and for the two groups as a whole. No relation between systolic or diastolic blood pressure and hearing loss was found, and equal proportions of each group had blood pressures exceeding 140/90 mm Hg. Persons with greater hearing loss (more than 60 dB at 4000 Hz) did not have significantly higher blood pressures than their matched controls.

A wide range of neuropsychiatric side effects are attributed to propranolol including visual hallucinations, somnulence, memory impairment, decrease in response time, dizziness, confusional states, insomnia, nightmares, fatigue, sedation and depression. Benson et al., in a summary review of several clinical studies of 5,846 patients being treated with a variety of beta adrenergic blocking agents, listed depression as a rare side effect of propranolol that was usually reported only after long term treatment at high doses. Despite the widely circulated attribution that depression is a side effect of propranolol, there is a paucity of evidence to directly link this drug with clinically significant mood disturbance. For example, the most widely quoted reference attributing propranolol as a depressogenic agent was a "letter to the editor" which was a retrospective, uncontrolled, unblinded study that did not use a standardized depression rating scale. Most of the evidence linking propranolol to depressive symptoms have derived from scattered case reports in which the onset of depressive symptoms were attributed to this agent. Given the well known cyclic onset and remissions of affective disorders, and the prevalence of depression in the general medical population as a whole, the role of propranolol in these cases is debatable.

Evidence is presented to show that ADP-ribosylation of nuclear proteins by poly(ADP-ribose) polymerase enhances template-primer activity of HeLa cell nuclear DNA. We used Escherichia coli DNA polymerase I (EC 2.7.7.7; DNA nucleotidyltransferase) as an exogenous probe of nuclear DNA status. Neither NAD nor free poly(ADP-ribose) acts directly on the bacterial enzyme. The stimulation is specific for formation of ADP-ribosylated proteins and is not a generalized polyanion or nucleotide effect on chromatin. The release of template restriction is proportional to the capacity of a given cell line to synthesize poly(ADP-ribose); both the stimulation and poly(ADP-ribose) formation are coordinately proportional to NAD concentration. Binding studies with DNA polymerase indicate exposure or generation of additional 3'-OH primer sites due to ADP-ribosylation in intact nuclei. With intact cells, there appears a correlation among growth, physiological template restriction, and the above effects of ADP-ribosylation.

Genetic studies with strain hisBH22 of Salmonella typhimurium indicate it contains a deletion within the histidine operon involving part of the hisH gene and all of the hisB gene, but not extending into the adjacent hisC gene which is adjacent to hisB. However, the specific activity of the hisC product, imidazolylacetolphosphate aminotransferase (EC 2.6.1.9), in this strain is only 10 to 15% of that found in extracts from other mutants with a normal hisC gene. We have examined the rate of aminotransferase synthesis in this mutant and we find that the rate of synthesis of aminotransferase activity is low in mutant hisBH22, but the rate increases as the temperature of growth is lowered from 37 to 23 C. The low rate of enzyme accumulation is not due to holoenzyme instability at 37 C but instead is due to apoenzyme instability at this temperature. By transducing the hisBH22 marker into a pyridoxine auxotroph and derepressing the histidine operon under conditions where the intracellular concentration of pyridoxal phosphate would be expected to be low, we were able to demonstrate significant apoenzyme production only at the lower temperature. We suggest that the explanation for low aminotransferase specific activity at 37 C is due to the presence of reduced numbers of catalytically active units caused by normal production of an unstable mutant apoenzyme with only approximately 15% of the molecules being activated to holoenzyme. The holoenzyme from strain hisBH22 is stable during growth of this strain at 37 C.

Public concern was expressed regarding the possibility of adverse health effects with the disposal of radioactive waste in Port Hope, Ontario. A case-control study was carried out to estimate the relative importance of domestic radon gas exposure in the causation of lung cancer in the town over a ten-year period. Twenty-seven cases met the entry criteria. Statistical analyses of results did not provide conclusive results that linked an increased risk of lung cancer and elevated domestic alpha radiation levels, when all factors were considered. However, a very strong association was demonstrated between cigarette smoking and lung cancer.