Incidence of type 2 diabetes, cardiovascular disease and chronic kidney disease in patients with multiple sclerosis initiating disease-modifying therapies: Retrospective cohort study using a frequentist model averaging statistical framework

Researchers are increasingly using insights derived from large-scale, electronic healthcare data to inform drug development and provide human validation of novel treatment pathways and aid in drug repurposing/repositioning. The objective of this study was to determine whether treatment of patients with multiple sclerosis with dimethyl fumarate, an activator of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, results in a change in incidence of type 2 diabetes and its complications. This retrospective cohort study used administrative claims data to derive four cohorts of adults with multiple sclerosis initiating dimethyl fumarate, teriflunomide, glatiramer acetate or fingolimod between January 2013 and December 2018. A causal inference frequentist model averaging framework based on machine learning was used to compare the time to first occurrence of a composite endpoint of type 2 diabetes, cardiovascular disease or chronic kidney disease, as well as each individual outcome, across the four treatment cohorts. There was a statistically significantly lower risk of incidence for dimethyl fumarate versus teriflunomide for the composite endpoint (restricted hazard ratio [95% confidence interval] 0.70 [0.55, 0.90]) and type 2 diabetes (0.65 [0.49, 0.98]), myocardial infarction (0.59 [0.35, 0.97]) and chronic kidney disease (0.52 [0.28, 0.86]). No differences for other individual outcomes or for dimethyl fumarate versus the other two cohorts were observed. This study effectively demonstrated the use of an innovative statistical methodology to test a clinical hypothesis using real-world data to perform early target validation for drug discovery. Although there was a trend among patients treated with dimethyl fumarate towards a decreased incidence of type 2 diabetes, cardiovascular disease and chronic kidney disease relative to other disease-modifying therapies-which was statistically significant for the comparison with teriflunomide-this study did not definitively support the hypothesis that Nrf2 activation provided additional metabolic disease benefit in patients with multiple sclerosis.

Prevalence and cardiometabolic correlates of ketohexokinase gene variants among UK Biobank participants

Essential fructosuria (EF) is a benign, asymptomatic, autosomal recessive condition caused by loss-of-function variants in the ketohexokinase gene and characterized by intermittent appearance of fructose in the urine. Despite a basic understanding of the genetic and molecular basis of EF, relatively little is known about the long-term clinical consequences of ketohexokinase gene variants. We examined the frequency of ketohexokinase variants in the UK Biobank sample and compared the cardiometabolic profiles of groups of individuals with and without these variants alone or in combination. Study cohorts consisted of groups of participants defined based on the presence of one or more of the five ketohexokinase gene variants tested for in the Affymetrix assays used by the UK Biobank. The rs2304681:G>A (p.Val49Ile) variant was present on more than one-third (36.8%) of chromosomes; other variant alleles were rare (<1%). No participants with the compound heterozygous genotype present in subjects exhibiting the EF phenotype in the literature (Gly40Arg/Ala43Thr) were identified. The rs2304681:G>A (p.Val49Ile), rs41288797 (p.Val188Met), and rs114353144 (p.Val264Ile) variants were more common in white versus non-white participants. Otherwise, few statistically or clinically significant differences were observed after adjustment for multiple comparisons. These findings reinforce the current understanding of EF as a rare, benign, autosomal recessive condition.

Changing levels of local crime and mental health: a natural experiment using self-reported and service use data in Scotland

Background

This study contributes robust evidence on the association between mental health and local crime rates by showing how changing exposure to small area-level crime relates to self-reported and administrative data on mental health.

Methods

The study sample comprised 112 251 adults aged 16–60 years, drawn from the Scottish Longitudinal Study, a 5.3% representative sample of Scottish population followed across censuses. Outcomes were individual mental health indicators: self-reported mental illness from the 2011 Census and linked administrative data on antidepressants and antipsychotics prescribed through primary care providers in the National Health Service in 2010/2012. Crime rates at data zone level (500–1000 persons) were matched to the participants’ main place of residence, as defined by general practitioner patient registration duration during 2004/2006, 2007/2009 and 2010/12. Average neighbourhood crime exposure and change in area crime were computed. Covariate-adjusted logistic regressions were conducted, stratified by moving status.

Results

In addition to average crime exposure during follow-up, recent increases in crime (2007/2009–2010/2012) were associated with a higher risk of self-reported mental illness, among ‘stayers’ aged 16–30 years (OR=1.11; 95% CI 1.00 to 1.22), and among ‘movers’ aged 31–45 years (OR=1.07; 95% CI 1.01 to 1.13). Prescribed medications reinforced these findings; worsening crime rates were linked with antidepressant prescriptions among young stayers (OR=1.09; 95% CI 1.04 to 1.14) and with antipsychotic prescriptions among younger middle-aged movers (OR=1.11; 95% CI 1.01 to 1.23).

Conclusion

Changing neighbourhood crime exposure is related to individual mental health, but associations differ by psychiatric conditions, age and moving status. Crime reduction and prevention, especially in communities with rising crime rates, may benefit public mental health.

A qualitative study exploring the health-related quality of life and symptomatic experiences of adults and adolescents with ulcerative colitis

Background

Ulcerative colitis (UC) often first presents during adolescence and early adulthood. Primary symptoms of UC are well known, yet similarities and differences of disease experience in adults and adolescents are not well characterized.

Methods

To understand the health-related quality of life (HRQoL) and symptomatic experience of UC, in-depth interviews were conducted in the US with 21 adults (20–70 years) and 14 adolescents (12–17 years). Eligibility and medical history were confirmed by clinician report. A previously conducted literature review and resultant conceptual model informed the discussion guide to explore symptoms and HRQoL. Age appropriate creative tasks (“animal” task and collage) were employed to facilitate discussion. Transcripts and collages were subjected to thematic analysis using ATLAS.ti software.

Results

Clinician-reported UC severity included 24% mild, 38% moderate, 38% severe among adults; and 64% mild, 29% moderate, 7% severe among adolescents. Among adults, 52% were female, 67% were white. Among adolescents, 50% were female, 71% were white. During analysis it was noted that all participants reported stomach/abdominal pain. Other key symptoms identified were frequent bowel movements, diarrhea, blood in stools, sudden need for bowel movement, stomach cramping, bloating, and feeling gassy/passing gas (≥75% of participants). Key impacts identified were embarrassment, dietary limitations, having to plan around UC, worry/fear, anger, low mood/depression, and relationship with others, (≥75% of participants). In creative tasks, animals were chosen to represent their UC and content included in the collages reflected the most commonly discussed themes from the interviews. Only adults discussed feeling dehydrated, while only adolescents discussed the impact of UC on school life.

Conclusions

Open-ended interviews highlighted the HRQoL and symptomatic experiences of UC from the patient’s perspective, which were similar between adult and adolescent UC patients.

Estimating the distribution of a novel clinical biomarker (FGF-23) in the US population using findings from a regional research registry

Evidence of involvement of novel biomarkers in disease pathogenesis from research cohorts often precedes an understanding of their distributions in broader populations. This study aimed to estimate the distribution of fibroblast growth factor 23 (FGF-23), an endocrine hormone that helps to regulate serum phosphate levels, in the overall US population and in important subgroups. We used a predictive model generated using data from the Framingham Health Study to estimate FGF-23 values for adults in the US National Health and Nutrition Examination Survey and the size of patient subgroups with levels of FGF-23 above selected thresholds. To assess the face validity of our FGF-23 estimates, we examined the relationship between estimated FGF-23 and cardiovascular and all-cause mortality within NHANES using Kaplan-Meier estimates and Cox proportional-hazards regression models and compared it to that observed in Framingham. Estimated FGF-23 values from NHANES were lower (median [interquartile range] 47.4 [35.8, 64.0] vs. 67.0 [54.0, 85.0] RU/mL) than the observed FGF-23 values from the Framingham cohort. Age- and sex-adjusted 10-year all-cause mortality was significantly higher (hazard ratio 2.43 [95% confidence interval: 1.42, 4.16]) for subjects with estimated FGF-23 levels in the highest versus lowest quartile. Estimating the distribution of biomarker values in the general population by applying predictive equations from smaller research cohorts is feasible and can inform drug research decision making.

The experience of social determinants of health within a Southern European Maltese culture

This study contributes to international research on geographies of health and wellbeing in Mediterranean cultures. The paper draws upon evidence from qualitative research in three localities in Malta, a country where previous research on this topic is quite limited. Through in-depth interviews with people from some of the most disadvantaged and socially marginalised groups in Maltese society, this research illustrates how psychosocial health and wellbeing of the inhabitants within this Mediterranean region are strongly influenced by wider social determinants, particularly the powerful dynamics of social norms involving roles of extended family, traditional attitudes towards marriage as an institution, family honour, gender roles and religious beliefs and practices. This research explores how these social determinants of health within a Maltese context are complex and contingent on personal and local socio-geographical conditions, so that while for some individuals they are beneficial for health and wellbeing, for others the effects are detrimental. The discussion considers how to interpret the 'Mediterranean model' of social determinants of health in light of the experiences of this group of inhabitants.

Medication adherence and improved outcomes among patients with type 2 diabetes

OBJECTIVES

Examine the association between adherence to glucose-lowering agents (GLAs) and patient outcomes in an adult type 2 diabetes (T2D) population.

STUDY DESIGN

Retrospective analysis.

METHODS

Truven's Commercial Claims and Encounters database supplied data from July 1, 2009, to June 30, 2014. Patients 18 to 64 years with T2D were included if they received a GLA from July 1, 2010, through June 30, 2011. Multivariable analyses examined the relationships among 3-year patient outcomes and adherence, defined as proportion of days covered 80% or more. Outcomes included all-cause medical costs, acute care resource utilization, and acute complications.

RESULTS

Although there was no statistically significant difference in total costs when comparing adherent and nonadherent patients ($38,633 vs $38,357; P = .0720), acute care costs ($12,153 vs $8233; P <.0001) and outpatient costs ($16,964 vs $15,457; P <.0001) were significantly lower for adherent patients. Adherence was also associated with a lower probability of hospitalization (22.71% vs 17.65%; P <.0001) and emergency department (ED) visits (45.61% vs 38.47%; P <.0001), fewer hospitalizations (0.40 vs 0.27; P <.0001) and ED visits (1.23 vs 0.83; P <.0001), and a shorter hospital length of stay (2.16 vs 1.25 days; P <.0001). Adherent patients were also less likely to be diagnosed with an acute complication in the 3-year post period (12.54% vs 9.64%; P <.0001).

CONCLUSIONS

Compared with nonadherence, adherence to GLAs among patients with T2D was associated with a significant reduction in acute care costs and resource utilization, outcomes that may positively impact the welfare of patients.

Physician perceptions of GLP-1 receptor agonists in the UK

Objectives Glucagon-like peptide-1 (GLP-1) receptor agonists have been used to treat type 2 diabetes for almost a decade, and new treatments in this class have recently been introduced. The purpose of this study was to examine perceptions of GLP-1 receptor agonists among physicians who treat patients with type 2 diabetes in the UK. Methods A total of 670 physicians (226 diabetes specialists; 444 general practice [GP] physicians) completed a survey in 2014. Results Almost all physicians had prescribed GLP-1 receptor agonists (95.4% total sample; 99.1% specialists; 93.5% GP), most frequently to patients whose glucose levels are not adequately controlled with oral medications (85.9% of physicians) and obese/overweight patients (83.7%). Physicians' most common reasons for prescribing a GLP-1 receptor agonist were: associated with weight loss (65.8%), good efficacy (55.7%), less hypoglycemia risk than insulin (55.2%), not associated with weight gain (34.5%), and better efficacy than oral medications (32.7%). Factors that most commonly cause hesitation when prescribing this class were: not considered first line therapy according to guidelines (56.9%), injectable administration (44.6%), cost (36.7%), gastrointestinal side effects (33.4%), and risk of pancreatitis (26.7%). Almost all specialists (99.1%) believed they had sufficient knowledge to prescribe a GLP-1 receptor agonist, compared with 76.1% of GPs. Conclusions Results highlight the widespread use of GLP-1 receptor agonists for treatment of type 2 diabetes in the UK. However, almost a quarter of GPs reported that they do not have enough knowledge to prescribe GLP-1s, suggesting a need for increased dissemination of information to targeted groups of physicians. Study limitations were that the generalizability of the clinician sample is unknown; survey questions required clinicians to select answers from multiple response options rather than generating the responses themselves; and responses to this survey conducted in 2014 do not reflect perceptions of the most recently introduced GLP-1 receptor agonists.

Clustered randomised controlled trial of two education interventions designed to increase physical activity and well-being of secondary school students: the MOVE Project

OBJECTIVE

To assess the effectiveness of 2 interventions in improving the physical activity and well-being of secondary school children.

DESIGN

A clustered randomised controlled trial; classes, 1 per school, were assigned to 1 of 3 intervention arms or a control group based on a 2×2 factorial design. The interventions were peer-mentoring and participative learning. Year 7 children (aged 11-12) in the peer-mentoring intervention were paired with year 9 children for 6 weekly mentoring meetings. Year 7 children in the participative learning arm took part in 6 weekly geography lessons using personalised physical activity and Global Positioning System (GPS) data. Year 7 children in the combined intervention received both interventions, with the year 9 children only participating in the mentoring sessions.

PARTICIPANTS

1494 year 7 students from 60 schools in the North of England took part in the trial. Of these, 43 students opted out of taking part in the evaluation measurements, 2 moved teaching group and 58 changed school. Valid accelerometry outcome data were collected for 892 students from 53 schools; and well-being outcome data were available for 927 students from 52 schools.

MAIN OUTCOME MEASURES

The primary outcomes were mean minutes of accelerometer-measured moderate-to-vigorous intensity physical activity per day, and well-being as evaluated by the KIDSCREEN-27 questionnaire. These data were collected 6 weeks after the intervention; a 12-month follow-up is planned.

RESULTS

No significant effects (main or interaction) were observed for the outcomes. However, small positive differences were found for both outcomes for the participative learning intervention.

CONCLUSIONS

These findings suggest that the 2 school-based interventions did not modify levels of physical activity or well-being within the period monitored. Change in physical activity may require more comprehensive individual behavioural intervention, and/or more system-based efforts to address wider environmental influences such as family, peers, physical environment, transport and educational policy.

TRIAL REGISTRATION NUMBER

ISRCTN82956355.

Preference for pharmaceutical formulation and treatment process attributes

PURPOSE

Pharmaceutical formulation and treatment process attributes, such as dose frequency and route of administration, can have an impact on quality of life, treatment adherence, and disease outcomes. The aim of this literature review was to examine studies on preferences for pharmaceutical treatment process attributes, focusing on research in diabetes, oncology, osteoporosis, and autoimmune disorders.

METHODS

The literature search focused on identifying studies reporting preferences for attributes of the pharmaceutical treatment process. Studies were required to use formal quantitative preference assessment methods, such as utility valuation, conjoint analysis, or contingent valuation. Searches were conducted using Medline, EMBASE, Cochrane Library, Health Economic Evaluation Database, and National Health Service Economic Evaluation Database (January 1993-October 2013).

RESULTS

A total of 42 studies met inclusion criteria: 19 diabetes, nine oncology, five osteoporosis, and nine autoimmune. Across these conditions, treatments associated with shorter treatment duration, less frequent administration, greater flexibility, and less invasive routes of administration were preferred over more burdensome or complex treatments. While efficacy and safety often had greater relative importance than treatment process, treatment process also had a quantifiable impact on preference. In some instances, particularly in diabetes and autoimmune disorders, treatment process attributes had greater relative importance than some or all efficacy and safety attributes. Some studies suggested that relative importance of treatment process depends on disease (eg, acute vs chronic) and patient (eg, injection experience) characteristics.

CONCLUSION

Despite heterogeneity in study methods and design, some general patterns of preference clearly emerged. Overall, the results of this review suggest that treatment process has a quantifiable impact on preference and willingness to pay for treatment, even in many situations where safety and efficacy were the primary concerns. Patient preferences for treatment process attributes can inform drug development decisions to better meet the needs of patients and deliver improved outcomes.

Associations between adherence and outcomes among older, type 2 diabetes patients: evidence from a Medicare Supplemental database

OBJECTIVE

To examine the association between adherence to glucose-lowering agents and patient outcomes, including costs, acute-care resource utilization, and complications, in an older, type 2 diabetic population.

DATA AND METHODS

The study used Truven's Medicare Supplemental database from July 1, 2009 to June 30, 2014. Patients aged 65 years or older were included if they had at least two type 2 diabetes diagnoses and received a glucose-lowering agent from July 1, 2010 through June 30, 2011. Multivariable analyses examined the relationships among 3-year patient outcomes and levels of adherence, proxied by the proportion of days covered. Outcomes included all-cause medical costs, diabetes-related medical costs, acute-care resource utilization, and acute complications.

RESULTS

In this study (N=123,235), higher adherence was linked to reduced costs and improved health outcomes. For example, comparing an individual with adherence of proportion of days covered <20% to one with proportion of days covered ≥80% illustrates an average saving of $28,824 in total 3-year costs. Furthermore, a 1% increase in adherence among 1,000 patients was associated with all-cause savings of $65,464 over 3 years. The probability of a hospitalization, an emergency room (ER) visit, or an acute complication decreased monotonically as adherence levels got higher, as did the number of hospitalizations, ER visits, and days hospitalized (P<0.005).

CONCLUSION

Higher adherence was associated with substantially less need for acute care, as indicated by a lowered probability of hospitalization or ER use, a reduced risk of an acute complication, and a decreased number of hospitalizations, ER visits, and days hospitalized. Higher adherence was also generally associated with lower all-cause and diabetes-related total costs, despite higher drug costs. These lower total costs were driven by the diminished acute care and outpatient costs. Results suggest that higher glucose-lowering agent adherence is associated with significant benefits for payers and older patients with type 2 diabetes.

Evaluating preferences for profiles of GLP-1 receptor agonists among injection-naïve type 2 diabetes patients in the UK

OBJECTIVE

To use a discrete choice experiment (DCE) to evaluate preferences for the actual treatment features and overall profiles of two injectable glucagon-like peptide-1 receptor agonists (dulaglutide and liraglutide) among patients with type 2 diabetes mellitus (T2DM) in the UK.

METHODS

In-person interviews were conducted in the UK to administer a DCE to patients with self-reported T2DM, naïve to treatment with injectable medications. The DCE examined six attributes of T2DM treatment each described by two levels: "dosing frequency," "hemoglobin A1c change," "weight change," "type of delivery system," "frequency of nausea," and "frequency of hypoglycemia." Part-worth utilities were estimated using random effects logit models and were used to calculate relative importance (RI) values for each attribute. A chi-square test was used to determine differences in preferences for dulaglutide versus liraglutide profiles.

RESULTS

A total of 243 participants [mean age: 60.5 (standard deviation 10.9) years; 76.1% male; mean body mass index: 29.8 (standard deviation 5.4) kg/m(2)] completed the study. RI values for the attributes in rank order were: "dosing frequency" (41.6%), "type of delivery system" (35.5%), "frequency of nausea" (10.4%), "weight change" (5.9%), "hemoglobin A1c change" (3.6%), and "frequency of hypoglycemia" (3.0%). Significantly more participants preferred the dulaglutide profile (83.1%) compared with the liraglutide profile (16.9%; P<0.0001).

CONCLUSION

This study elicited patients' preferences for attributes and levels representing the actual characteristics of two specific glucagon-like peptide-1 medications. In this context, dosing frequency and type of delivery system were most important, accounting for over 75% of the RI. While previous studies have identified efficacy as highly important in T2DM medication decisions, this study suggests that when differences in efficacy between medications are small, other treatment features (eg, dosing frequency and delivery system) are of much greater importance to patients.

A model of mild hypoglycemia

OBJECTIVE

To investigate the impact associated with mild hypoglycemia among patients with type 2 diabetes (T2DM) in the United States and to identify risk factors among different subpopulations.

METHODS

We performed a literature search to gather available data allowing estimation of rates of mild hypoglycemia. Because risk factors are interdependent, risk factors included in the model were based on those reported within multivariate analyses or judged to be biologically plausible by the medical community. Based on literature search results, we built a mathematical model predicting the rates of mild hypoglycemia in individual patients as a function of the patient's antidiabetic medications, hemoglobin A1c levels, duration of diabetes, kidney function, and body mass index.

RESULTS

We estimated an overall average rate of mild hypoglycemia among US patients with T2DM of 2.2 ± 0.8 events per person per year. Patients taking oral antidiabetic medications only had an average rate of 1.9 ± 0.8 events per person per year. The average rate for all patients taking insulin, including those combining it with other antidiabetic medications, was 4.9 ± 2.0 events per person per year. Mild hypoglycemia rates increased with age, with 80-year-old patients experiencing 1.5 times the risk of 40-year-old patients. Based on published values for direct and indirect medical costs for mild hypoglycemia events, we determined that the economic impact in the US of mild hypoglycemic events is approximately $900 million per year, roughly equal to that of severe hypoglycemic events. One of the key limitations to our model is that it applies to the US population under standard medical care and not to clinical trials and does not include certain known risk factors such as rigorous exercise.

CONCLUSIONS

Understanding the benefit versus risk of glycemic control and hypoglycemia is fundamental to the successful management of patients with T2DM. Our validated hypoglycemia model is an important step in addressing this issue and may be helpful to researchers, clinicians, and payers to determine the patients who are at the highest risk for hypoglycemia, whether a patient is experiencing events at 'higher-than-expected' rates, and the corresponding economic burden.

'Therapeutic landscapes' and the importance of nostalgia, solastalgia, salvage and abandonment for psychiatric hospital design

We examine emotional reactions to changes to medical spaces of care, linked with past experiences. In this paper we draw on findings from a qualitative study of the transfer of psychiatric inpatient care from an old to a newly built facility. We show how the meanings attributed to 'therapeutic landscapes' from one׳s past can evoke emotions and memories, manifesting in ideas about nostalgia, solastalgia, salvage and abandonment, which can impinge on one׳s present therapeutic experience. We reflect on how consideration of these ideas might contribute to better future design of psychiatric inpatient facilities and the wellbeing of those using them.

Spaces for smoking in a psychiatric hospital: social capital, resistance to control, and significance for 'therapeutic landscapes'

This paper reports on research framed by theories of therapeutic landscapes and the ways that the social, physical and symbolic dimensions of landscapes relate to wellbeing and healing. We focus especially on the question of how attributes of therapeutic landscapes are constructed in different ways according to the variable perspectives of individuals and groups. Through an ethnographic case study in a psychiatric hospital in the North of England we explore the perceived significance for wellbeing of 'smoking spaces' (where tobacco smoking is practiced in ways that may, or may not be officially sanctioned). We interpret our findings in light of literature on how smoking spaces are linked to the socio-geographical power relations that determine how smoking is organised within the hospital and how this is understood by different groups using the hospital building. We draw on qualitative research findings from discussion groups, observations, and interviews with patients, carers and staff. These focused on their views about the building design and setting of the new psychiatric hospital in relation to their wellbeing, and issues relating to smoking spaces emerged as important for many participants. Creating and managing smoking spaces as a public health measure in psychiatric hospitals is shown to be a controversial issue involving conflicting aims for health and wellbeing of patients and staff. Our findings indicate that although from a physical health perspective, smoking is detrimental, the spaces in which patients and staff smoke have social and psychological significance, providing a forum for the creation of social capital and resistance to institutional control. While the findings relate to one case study setting, the paper illustrates issues of wider relevance and contributes to an international literature concerning the tensions between perceived psychological and psychosocial benefits of smoking vs. physical harm that smoking is likely to cause. We consider the implications for hospital design and the model of care.

Neighbourhood deprivation and adolescent self-esteem: exploration of the 'socio-economic equalisation in youth' hypothesis in Britain and Canada

Material deprivation is an important determinant of health inequalities in adults but there remains debate about the extent of its importance for adolescent wellbeing. Research has found limited evidence for an association between adolescent health and socio-economic status, leading authors to suggest that there is an ‘equalisation’ of health across socio-economic groups during the adolescent stage of the life-course. This paper explores this ‘equalisation’ hypothesis for adolescent psychological wellbeing from a geographical perspective by investigating associations between neighbourhood deprivation and self-esteem in Britain and Canada. Data from the British Youth Panel (BYP) and the National Longitudinal Survey of Children and Youth (NLSCY) on adolescents aged 11–15 for the time period 1994–2004 were used to estimate variations in low self-esteem between neighbourhoods using multilevel logistic regression. Models were extended to estimate associations between self-esteem and neighbourhood deprivation before and after adjustment for individual and family level covariates. Moderation by age, sex, urban/rural status, household income and family structure was investigated. There were no significant differences in self-esteem between the most deprived and most affluent neighbourhoods (Canada unadjusted OR = 1.00, 95% CI 0.76, 1.33; Britain unadjusted OR = 1.25, 95% CI 0.74, 2.13). The prevalence of low self-esteem was higher (in Canada) for boys in the least deprived neighbourhoods compared to other neighbourhoods. No other interactions were observed. The results presented here offer some (limited) support for the socio-economic equalisation in youth hypothesis from a geographical perspective: with specific reference to equalisation of the relationship between neighbourhood deprivation and self-esteem and psychological health in early adolescence. This contrasts with previous research in the United States but supports related work from Britain. The lack of interactions with key social and economic variables suggests that findings might apply across a range of family circumstances and different communities in Britain and Canada. Policy implications are discussed.

Creating 'therapeutic landscapes' for mental health carers in inpatient settings: a dynamic perspective on permeability and inclusivity

Although there has been a shift toward treatment in the home and the community, in the UK, inpatient facilities are still important in modern mental health care. 'Informal carers', including family members, often play an essential role, not only in providing care in the community but also in care of patients during periods of hospitalisation. UK National Health Service policies increasingly consider the position of these carers as 'partners' in the care process, but relatively little attention has been paid to their position within the hospital settings where treatment is provided for inpatients. This paper contributes to geographical work on carers experiences, by reporting how this issue emerged through a study focused on perceptions of a newly built hospital, compared with the inpatient facilities it replaced. We draw on qualitative research findings from discussion groups and interviews with informal carers. The material considered here focused especially on carers' views of aspects of the hospital environment that were important for wellbeing of carers and the people they look after. The carers' views were supplemented by relevant material drawn from other interviews from our wider study, which included service users and members of hospital staff. These accounts revealed how informal carers experienced the hospital environment; we interpret our findings through a conceptual framework that emphasises carers' experiences of a 'journey' along a 'caring pathway' to and through the hospital space. This perspective allows us to make a connection between three bodies of literature. The first relates to phenomenological interpretations of one's environmental perception, formed as one moves through the world. The second derives from the literature concerning 'permeability' of hospital institutions. Bringing these ideas together provides an innovative, dynamic perspective on a third strand of literature from health geography that examines hospitals as 'therapeutic landscapes'. The analysis helps to explore the extent to which carers in this study were positioned as 'outsiders' in the hospital space.

Effects of floor space during transport and journey time on indicators of stress and transport losses of market-weight pigs

The effects of floor space on the trailer and journey time during transport from the farm to the packing plant on indicators of stress (open-mouth breathing, muscle tremors, and skin discoloration) and on the incidence of transport losses (dead on arrival, nonambulatory, noninjured, and nonambulatory, injured) were evaluated in a study involving 160 loads of market-weight pigs (BW 124.7 ± 4.38 kg) using a split-plot design with a 2 × 6 factorial arrangement of treatments: 1) journey time [main plot; short (<1 h) and long (3 h)] and 2) floor space (subplot; 0.396, 0.415, 0.437, 0.462, 0.489, and 0.520 m(2)/pig, which is equivalent to 0.317, 0.332, 0.350, 0.370, 0.391, and 0.416 m(2)/100 kg of BW, respectively). Two consecutively loaded trailers were randomly allotted to journey time treatment. Floor space treatments were compared in the front 3 compartments on the top and bottom decks of the trailer and were created by varying the number of pigs per compartment, which confounds the effect of floor space with group size. Of the 17,652 pigs transported in 954 test compartments, 0.24% died or became nonambulatory. Neither journey time nor floor space had an effect (P > 0.05) on the incidence of dead and nonambulatory, injured pigs, or on total transport losses. There were interactions (P < 0.05) between journey time and floor space treatments for the incidences of nonambulatory, noninjured pigs and open-mouth breathing. For 2 of the smallest floor spaces (0.415 and 0.437 m(2)/pig), the incidence of nonambulatory, noninjured pigs was greater on short than on long journeys; for the other 4 floor spaces there was no effect (P > 0.05) of journey time. The incidence of open-mouth breathing for the 3 smallest floor spaces was greater (P < 0.05) for short than long journeys, whereas there was no effect (P > 0.05) of journey time for the 3 greatest floor spaces. The frequency of skin discoloration was greater (P < 0.001) for pigs transported at the 2 smallest floor spaces compared with the other 4 floor spaces. In summary, short journey time increased the frequency of indicators of stress after unloading at the plant for pigs transported at smaller floor spaces and also increased the incidence of nonambulatory, noninjured pigs at 2 of the 3 smallest floor spaces. However, neither transport floor space nor journey time had an effect on total losses.

The geography of institutional psychiatric care in France 1800-2000: historical analysis of the spatial diffusion of specialised facilities for institutional care of mental illness

As in other European countries, specialised psychiatric hospitals were established throughout France during the 19th Century. The construction of these hospitals can be considered as the concrete expression of a therapeutic innovation which recognized insanity as an illness that could be treated in such specialised institutions. The spatial diffusion of these innovative institutions through 19th and 20th century France is analysed and we explore how far this can be understood through theories of diffusion of innovations including geographical models of hierarchical and expansion diffusion (or whether other conceptual models are more appropriate). The research reported here particularly focuses on the period 1800-1961. It involved the construction of an original historical database of both psychiatric hospitals and information on the cities where these institutions were located. This was used to examine and interpret the different phases of development of psychiatric institutions and the parts of the country and types of geographical setting where they were concentrated. A multiple correspondence analysis was then performed to examine the connections between different aspects of the diffusion process. The study shows the limitations of classical models of spatial diffusion, which are found to be consistent with some, but not all aspects of the development of psychiatric institutions in France. An alternative political ecology approach seems more appropriate to conceptualise the various processes involved; national policies, social representations, medicalisation of care of mental illness, and urban and economic growth all seem to be associated with the emergence of a variable and complex pattern. This paper also opens a large field of research. Compared with other western countries, the geography of French psychiatric care is relatively under-researched, although there has been a strong spatial dimension to mental health policy in the country. This analysis provides a context for studies of more contemporary processes of French deinstitutionalisation, which is strongly structured by the past heritage of these large asylum facilities.

Isolation and sequence of the gene for the large subunit of ribulose-1,5-bisphosphate carboxylase from the cyanobacterium Anabaena 7120

Cloned DNA probes containing genes coding for the large subunit of ribulose-1,5-bisphosphate carboxylase (rbcA) of corn and of Chlamydomonas were used to identify, by heterologous hybridization, DNA fragments from Anabaena 7120 carrying the corresponding gene sequence. The same probes were used to isolate, from a recombinant lambda library, a 17-kilobase-pair EcoRI Anabaena DNA fragment containing the coding sequence for the rbcA gene. The entire coding sequence, as well as 210 base pairs of 5' flanking region and 210 base pairs of 3' flanking region, was determined. Comparison of the nucleotide and amino acid sequences with those of corn, spinach, Chlamydomonas, and Synechococcus rbcA genes revealed homology of 71-77% at the nucleotide level and 80-85% at the amino acid level. Conservation of sequence is lost immediately outside the coding region on either side. Codon usage in the Anabaena rbcA gene is not significantly different from that in the Anabaena genes for nitrogenase reductase and nitrogenase beta subunit.

Frequency of the HAL-1843 mutation of the ryanodine receptor gene in dead and nonambulatory-noninjured pigs on arrival at the packing plant

Four Midwestern packing plants (designated as plants A, B, C, and D) were visited on 53 occasions, and tissue samples were collected postmortem from a total of 2,019 pigs to determine the frequency of the HAL-1843 mutation of the ryanodine receptor gene in dead (DOA), nonambulatory-noninjured (NANI), and normal animals. The sampled pigs came from approximately 130,000 animals from 454 farms and were transported on 861 trailer loads, with an average of 152 pigs/load and an average pig live BW/load of 125 (SD 7.02) kg/pig. Frequency of animals with the HAL-1843 mutation was low, with only 2.7% of the pigs being either homozygous recessives (nn, 0.45%) or carriers (Nn, 2.3%) for the mutation and 97.3% of the pigs being homozygous for the normal allele (NN). The mutation was present in all 3 classes of pig, with 1.8% of normal, 1.8% of NANI, and 4.7% of DOA animals having at least 1 copy. Two of the plants (A and C) had a greater frequency (P < 0.05) of carrier (3.7 and 3.5 vs. 1.1 and 1.0 for plants A and C vs. B and D, respectively) and homozygous recessive (1.0 and 0.9 vs. 0.0 and 0.0, respectively) animals than the others (plants B and D). There was a greater frequency (P < 0.05) of carriers in DOA animals than in the normal or NANI pigs (3.7 vs. 1.7 and 1.5 for DOA vs. normal and NANI, respectively). The 55 pigs that had at least 1 copy of the mutation came from 53 farms; therefore, the mutation was relatively widespread, being present in approximately 11% of the farms sampled. Although the HAL-1843 mutation is still present in commercial pig populations in the United States, its low frequency in DOA and NANI pigs suggests that it is not a major cause of these transport losses.

Space allowance for dry, pregnant sows in pens: Body condition, skin lesions, and performance1

Different floor space allowances for dry, pregnant sows in pens were evaluated to determine the impacts of space on sow performance, productivity, and body lesions during 2 consecutive farrowings. Treatment groups of 5 sows/pen were assigned to 1.4, 2.3, or 3.3 m(2) of floor space/sow or of 5 sows in individual stalls (1.34 m(2)). The experiment consisted of 6 replications (blocks 1 to 6), and within each block measurements were recorded for 2 consecutive pregnancies and farrowings. A total of 152 sows were measured at 1 farrowing, and 65 of those sows were measured at the successive farrowing (n = 217 records). Performance traits were BCS, BW, backfat (BF), days until rebred, and proportion culled. Litter traits were number of piglets born alive, male:female ratio, and proportions of stillborn, mummified, or dead piglets after birth. Litter performance measures were mean piglet BW and gain and litter BW. Lesion scores were assessed for several body regions. There were treatment and parity effects and interactions for several traits. An interaction of space treatment and parity occurred for sow mean BW, d-110 BW, BF, litter size, and litter and piglet BW and gain, with most effects in parity 2, 3, and 4 sows. Space affected sow mean (P < 0.001) and d-110 BW (P < 0.05) and mean BF and adjusted BF (P < 0.001); sows in pens at </=2.3 m(2) of space had greater (P < 0.05) BW and BF depth, and primiparous sows had less (P < 0.05) BW than greater parity sows. Few differences were found for litter traits, except for litter size, litter weaning BW, and pig BW gain. Sows in pens at 3.3 m(2) had the largest (P < 0.05) litters. Weaning BW was greater (P < 0.05) for litters born to sows that gestated in stalls. Sow BCS and lesion score were affected by floor space (P < 0.001) and parity (P < 0.01); BCS was reduced in sows in pens at 1.4 m(2), and their lesion score was consistently greater (P < 0.05) than that of other space allowances. Primiparous sows often had the least (P < 0.05) lesion scores. For sows in pens, linear and quadratic responses were detected for many of the traits assessed. As floor space increased, BW and BF increased (P < 0.01), but as space decreased, lesion scores increased. Although the effects of gestation system were found and lesion scores often were greater as space decreased, differences in productivity traits were unremarkable with respect to sow welfare or performance compared with industry norms.

Effects of proportion of pigs removed from a group and subsequent floor space on growth performance of finishing pigs1

The effects of the proportion of pigs removed from an established group and subsequent floor space on growth performance during the final 19 d of the finishing period were evaluated using 28 pens of mixed-sex crossbred pigs (mean initial BW = 113.4 +/- 0.57 kg; n = 1,456; approximately 52 pigs per pen). A randomized block design was used with four pig-removal treatments: 1) 0% of pigs removed [Control], 2) approximately 25% of pigs removed, 3) approximately 50% of pigs removed, and 4) approximately 50% of pigs removed and floor and feeder spaces/pig decreased to equal those of Control. A block consisted of four pens with the same number of pigs and sex ratio per pen and with similar initial BW. Pens within blocks were randomly allocated to treatment, and the heaviest animals were removed from Treatments 2, 3, and 4 at the start of the study. Group size and floor space/pig for Treatments 1, 2, 3, and 4 were 52 and 0.65 m(2), 39 and 0.87 m(2), 26 and 1.30 m(2), and 26 and 0.65 m(2), respectively. Each pen contained a six-place feeder that provided 212 cm of total trough space; however, only three-places were accessible to pigs on Treatment 4. Compared with Controls, removing 25 or 50% of pigs resulted in increased (P < 0.001) ADG by 20.6 and 21.0%, ADFI by 10.8 and 7.9%, and G:F by 7.7 and 14.3%, respectively. Average daily gain by pigs on Treatment 4 (50% removal rate and decreased floor and feeder spaces) was greater (P < 0.05) than that of the Controls, but lower (P < 0.05) than that of Treatment 3 pigs (50% removal rate, no adjustment in floor or feeder spaces). No differences were observed among treatments for either morbidity or mortality. These results indicate that removing 25 or 50% of the heaviest pigs from groups of finishing pigs increased growth rate of the remaining pigs, and that the improved performance was only partly due to increased floor and feeder spaces.

Effect of restricted postweaning growth resulting from reduced floor and feeder-trough space on pig growth performance to slaughter weight in a wean-to-finish production system

The effect of reduced pig growth rate postweaning as a result of restricted floor space and feeder trough space on subsequent growth to slaughter was investigated in a wean-to-finish system. Crossbred pigs (n = 1,728) were used in a randomized block design with a 2 x 2 x 2 factorial arrangement of treatments: 1) floor space (high [0.630 m2/pig] vs. low floor space [0.315 m2/pig]), 2) feeder trough space (unrestricted [4 cm/pig] vs. restricted feeder trough space [2 cm/pig]), and 3) period of imposing floor- and feeder-trough-space treatments (12 vs. 14 wk postweaning). Growth performance was measured from weaning (5.5 +/- 0.01 kg of BW; 17 d of age) to slaughter (the end of wk 25 postweaning). From the end of the treatment period to the end of wk 25, pigs on all treatments had the same floor and feeder trough space. Pigs with low floor space had lower (P < 0.01) ADG, ADFI, and gain:feed ratio than those with high floor space, and were therefore lighter (P < 0.05) at the end of the postweaning treatment period. Pigs given the restricted feeder trough space had lower (P < 0.05) ADFI, similar (P > 0.05) ADG, and higher (P < 0.01) gain:feed ratio than those with unrestricted feeder trough space during the treatment period. Pigs in the 14-wk treatment period had higher (P < 0.01) ADG and ADFI, but lower gain:feed than those in the 12-wk treatment during that period. In the subsequent period, from the end of treatment to wk 25, there was an interaction (P < 0.05) between floor space and treatment period; the difference in ADG and gain:feed for pigs on low vs. high floor space was greater for the 14-wk than the 12-wk treatment period. However, low-floor-space pigs tended (P = 0.06) to be lighter than high-floor-space pigs at the end of wk 25 postweaning. Neither feeder trough space nor treatment period affected pig growth performance during the period from the end of treatment to wk 25. Carcass backfat and longissimus depths at the end of wk 25 were not influenced (P > 0.05) by treatment. In summary, pigs with restricted growth due to low floor space until either 12 or 14 wk postweaning had increased growth and feed efficiency in the subsequent period to wk 25 postweaning, with only a slight effect on BW and no effect on carcass measures.

Impact of early postweaning growth rate as affected by diet complexity and space allocation on subsequent growth performance of pigs in a wean-to-finish production system

The objective was to evaluate the effect of restricted early postweaning growth rate due to diet complexity, pen space, or both on subsequent growth to market in a wean-to-finish system. Pigs (n = 1,728) were used in a randomized block design with a 2 x 2 factorial arrangement of treatments: 1) diet complexity (Complex vs Simple) and 2) space allocation (Unrestricted vs Restricted). Treatments were imposed for the first 8 wk after weaning (period 1) and growth was measured from weaning (5.0 +/- 0.01 kg body weight; 15 d of age) to the end of wk 23 postweaning. The Simple diet was based on corn-soybean meal with minimal inclusion of milk products, processed cereals, and animal protein-based ingredients compared to the Complex diet. Floor and feeder-trough spaces were 0.63 m2 and 4 cm and 0.21 m2 and 2 cm per pig for Unrestricted and Restricted space treatments, respectively. From the end of wk 8 to end of wk 23 (period 2), pigs on all treatments had the same floor and feeder spaces and were fed common diets. There was no interaction (P > 0.05) between diet and space treatments. In period 1, Simple diets resulted in similar average daily feed intake (ADFI; 639 vs 650 +/- 5.4 g; P > 0.05), but lower average daily gain (ADG; 408 vs 424 +/- 3.8 g; P < 0.01) and gain:feed ratio (0.64 vs 0.65 +/- 0.002; P < 0.001), and lighter body weight (2.8%; P < 0.01) compared to the Complex diets. In period 2, growth was not affected (P > 0.05) by previous diet complexity, and pig body weight was similar (114.4 vs 114.4 +/- 0.37 kg, P > 0.05) at the end of wk 23. In period 1, pigs with Restricted space had lower ADG (398 vs 434 +/- 3.8 g; P < 0.001), ADFI (621 vs 668 +/- 5.4 g; P < 0.001), and gain:feed ratio (0.64 vs 0.65 +/- 0.002; P < 0.01), and were lighter at the end of wk 8 (6.5%; P < 0.001) than those with Unrestricted space. However, in period 2, pigs with Restricted space had higher (P < 0.01) ADG (3%), ADFI (2%), and gain:feed ratio (3%) than those with Unrestricted space, and body weight was similar (114.5 vs 114.3 +/- 0.37 kg; P > 0.05) at end of wk 23. Carcass backfat and loin-eye depth at market body weight were influenced by neither diet nor space treatment. Using a simple diet program and restricted space allowance immediately postweaning resulted in a lower early growth rate, but had no impact on pig body weight or carcass measures at market.

Effects of feeder-trough space and variation in body weight within a pen of pigs on performance in a wean-to-finish production system

Two studies were carried out with the same group of pigs within a wean-to-finish system. In Study 1 (weaning to wk 8 postweaning), the effect of feeder-trough space in pens that were double-stocked on pig growth was evaluated. In Study 2 (end of wk 8 to 112 +/- 1.5 kg BW), the effect of variation in pig BW within a pen on growth was investigated. In Study 1, a randomized block design was used to compare two feeder-trough space treatments (Double [4 cm/pig] vs Control [2 cm/pig]). Pigs (n = 1,728) were randomly allocated at weaning (5.4 +/- 0.01 kg BW; 16 d of age) to mixed-sex pens (8 pens/treatment) of 108 pigs/pen on the basis of BW. Floor-space (0.30 m2/pig) and drinker allocation (13 pigs/drinker) were the same for both treatments. Two six-place (35 cm/place) feeders were positioned together in the center of each pen and were accessible from both sides. For the Double treatment, both feeders contained feed, whereas for the Control only one feeder contained feed. In Study 2, a randomized block design was used to compare three BW/variation in BW treatments: 1) Heavy BW/Low variation, 2) Light BW/Low variation, and 3) Mixed BW/Normal variation. The double-stocked pens of pigs from within previous feeder-trough space treatment were split into two groups of 54 pigs (equal sex ratio) having either high or low BW variation within pen. Pigs had free access to feed and water throughout the studies. In Study 1, doubling feeder-trough space did not affect (P > 0.05) pig growth from weaning to the end of wk 6. From wk 6 to 8, pigs on the Double treatment compared to the Control treatment had higher (P < 0.05) ADG and were heavier (P < 0.05), but had similar (P > 0.05) ADFI and gain:feed ratio. In Study 2, pen-BW treatment did not impact (P > 0.05) ADG or gain:feed ratio; however, Heavy/Low had greater (P < 0.01) ADFI than Light/Low with Mixed/Normal being intermediate for ADFI. At 112 kg BW, CV of BW within a pen was similar (P > 0.05) across treatments; however, days to market BW was greater (P < 0.001) for Light/Low than Heavy/ Low with Mixed/Normal being intermediate. In summary, increasing feeder-trough space from 2 to 4 cm per pig increased daily gain after wk 6 postweaning in double-stocked pens of pigs; however, sorting pigs on the basis of BW when splitting pens did not impact growth rate or variation in BW within a pen at market BW.

Effects of double stocking and weighing frequency on pig performance in wean-to-finish production systems

Two studies were carried out in different wean-to-finish barns to determine the effects of double stocking on pig growth performance. In Study 1, pigs (n = 1,560) were used in a randomized complete block design with a 2 x 2 factorial arrangement of treatments: initial stocking treatment (Single [52 pigs/pen] vs Double [104 pigs/pen] stocked for 10 wk after weaning) and weighing frequency (High [12 times during the study] vs Low [3 times]) on pig performance from weaning (5.9+/-0.01 kg BW; 17 d of age) to harvest (114+/-0.67 kg BW). Floor and feeder space per pig were 0.650 m2 and 4 cm and 0.325 m2 and 2 cm for the single- and double-stocked treatments, respectively. In Study 2, pigs (n = 1,458) were used in a randomized complete block design to evaluate two initial stocking treatments (Single [27 pigs] vs Double [54 pigs] stocked for 10 wk after weaning) on pig performance from weaning (4.8+/-0.01 kg BW; 15 d of age) to harvest (24 wk after weaning). Floor and feeder space per pig were 0.640 m2 and 3.4 cm and 0.320 m2 and 1.7 cm for single- and double-stocked pens, respectively. In both studies, double-stocked pigs were split at the end of wk 10 into two equal-sized groups of similar mean BW and CV of BW, and one group was moved to a different pen in the same building. In Study 1, performance was not affected (P > 0.10) by frequency of weighing. For the first 10 wk after weaning, the Double compared to the Single treatment had lower ADG (7.7 and 7.9%, for Studies 1 and 2, respectively; P < 0.001) and lighter pigs at wk 10 (6.8 and 7.3%, respectively; P < 0.001). During the first 10 wk in Study 1, Double compared to the Single pigs had lower ADFI (7%; P < 0.001) but similar gain:feed (P > 0.10). From wk 11 to harvest, pigs on Double and Single treatments had similar (P > 0.10) ADG in both studies and, in Study 1, ADFI was unaffected by initial stocking treatment, but double-stocked pigs had greater gain:feed (4%, P < 0.01). Double-stocked pigs required an additional 2 d to reach a fixed harvest BW (P < 0.05) in Study 1 and were lighter (4%; P < 0.05) at 24 wk after weaning in Study 2. Carcass measures were similar (P > 0.10) for double- and single-stocked pigs. Double-stocked pigs that were moved at the end of 10 wk had growth performance similar (P > 0.10) to those that remained in the original pen. In summary, double stocking reduced growth rate to 10 wk after weaning but subsequently had no effect on growth rate and improved feed efficiency.

Effect of group size on pig performance in a wean-to-finish production system

Crossbred pigs (n = 1,400) were used to evaluate the effect of group size (25 vs 50 vs 100 pigs/pen) in a wean-to-finish production system on growth performance and carcass measures. Pigs were weaned at 17 d (range = 15 to 19) of age with a mean initial BW of 5.9 +/- 0.02 kg and taken to a final mean pen weight of 116 +/- 0.9 kg. A 10-phase dietary regimen was used, and pigs had free access to feed and water. Feeder-trough space (4.3 cm/pig) and floor-area allowance (0.68 m2/pig) were the same for all group sizes. Compared to groups of 25, pigs in groups of 50 and 100 animals were lighter (P < 0.001) at the end of wk 8 after weaning and had lower (3%, P < 0.01) ADG and gain:feed (G/F) but similar (P > 0.05) ADFI during the first 8 wk of the study. At the end of the study, pig weight and the coefficient of variation in pig weight within a pen were similar (P > 0.05) across group sizes. During the period from 8 wk after weaning to the end of the study, pigs in groups of 100 compared to 50 animals had greater (3%, P < 0.01) ADG, and pigs in groups of 25 were intermediate for ADG. Average daily feed intake during this period was similar (P > 0.05) for all group sizes; however, G/F was greater (3%, P < 0.01) for groups of 100 compared to 25 or 50 animals. For the overall study period, ADG, ADFI, and G/F from weaning to slaughter weight were similar across group sizes (P > 0.05; 655, 648, and 658 g; 1,759, 1,755, and 1,759 g; and 0.37, 0.37, and 0.37; for ADG, ADFI, and G/F, respectively, for groups of 25, 50, and 100 pigs, respectively). Mortality was similar (P > 0.05) across group sizes; however, morbidity (pigs removed due to poor health or injury) was higher in groups of 25 pigs compared to the other two group sizes (7.0, 3.5, and 3.9% for groups of 25, 50, and 100, respectively; P < 0.05). Group-size treatment did not affect (P > 0.05) carcass dressing percentage, backfat thickness, or loin-eye depth. In summary, growth performance from weaning to market weight was not affected by group size.

A screen for sequences up-regulated during heterocyst development in Anabaena sp. strain PCC 7120

A plasmid library of small genomic fragments from the cyanobacterium Anabaena sp. strain PCC 7120 was screened for sequences whose transcripts increase in abundance during a heterocyst development time course. A total of 350 clones were analyzed, representing 1-2% of the Anabaena sp. strain PCC 7120 genome. Twenty-seven clones (8%) showed some degree of up-regulation after nitrogen starvation. The increase in transcript abundance ranged from 1.2-fold to 3.5-fold. Further analysis of the expression of some of the sequences using Northern blots suggested that the up-regulation values calculated from the screen are underestimates. The collection of up-regulated clones includes novel genes, previously characterized genes, and genes identifiable by similarity to known genes. One of the novel genes has been shown to be required for heterocyst function, and the sequence similarities and expression patterns of some of the others suggest that they may play a role in heterocyst development.

Feeder location did not affect performance of weanling pigs in large groups

Crossbred pigs weaned at 17 d of age (n = 1,760; mean initial BW = 5.6 +/- 0.7 kg) were used in two 4-wk trials (four replicates per trial) to evaluate the effects of three pen designs on pig performance. The designs were 1) large group size (100 pigs/pen) with five two-sided feeders in a single, central location in the pen; 2) large group size (100 pigs/pen) with five two-sided feeders in multiple (five) locations in the pen; and 3) small group size (20 pigs/pen) with a single two-sided feeder in a central location in the pen. Each feeder provided two 20.3-cm-wide feeding places on each side. Pigs had free access to feed and water. Feeder-trough space (4 cm/pig) and floor-area allowance (0.17 m2/pig) were the same for all treatments. Pigs in the large-group treatments were lighter (15.6 and 15.6 vs 16.0 kg; P < 0.01) at the end of wk 4 and had lower ADG (358 and 357 vs 373 g; P < 0.01) and ADFI (510 and 521 vs 544 g; P < 0.01) during wk 2 through 4 than pigs in small groups. Gain:feed ratio was similar (P > 0.05) for all treatment groups throughout the study. For large groups, feed disappearance from each of the five feeders was similar (P > 0.05) for both multiple- and single-location treatments. In summary, large group size reduced pig growth performance, but the approach to providing multiple feeding locations that was employed in this experiment did not increase feed intake or growth performance of pigs in the large groups.

Group size and floor-space allowance can affect weanling-pig performance

Crossbred weanling piglets (n = 1,920; mean initial BW, 5.3 +/- .7 kg) were used in two 9-wk trials employing a randomized block design in a 2 x 2 factorial arrangement of treatments to determine effects of group size (20 [Small = S] or 100 [Large = L] pigs/pen) and floor-space allowance (calculated requirement [CR] or calculated requirement less 50% of estimated "free space" [CR-50]) on growth performance. Free space was estimated for each group size. From wk 1 through 4 after weaning, S and L groups at CR were allowed a floor space of .17 m2/pig, and at CR-50, S and L groups were allowed .15 m2/pig and .13 m2/pig, respectively. From wk 5 through 9 after weaning, all CR treatment pigs were provided a floor space of .38 m2/pig, and for the CR-50 treatment, S and L pigs were allowed .32 m2/pig and .28 m2/pig, respectively. Piglets had free access to feed and water. Feeder-trough space per pig was the same for both group sizes. Feed-intake data were collected for only wk 1 through 4. Group size by floor-space allowance interactions (P < .05) were found for gain/feed ratio (G/F) for wk 1 and wk 2 through 4, but not for wk 1 through 4. Piglets in L groups were lighter (P < .001) at the end of wk 1, 4, and 9 by 2, 4, and 5%, respectively, and had lower ADG (6%; P < .001) throughout the trial than S piglets. During wk 1 through 4, feed intake was lower (7%, P < .001) in L piglets than in S piglets, but G/F was similar (P > .05). Piglets in CR groups had greater ADG (5%; P < .01) throughout the trial, with a greater G/F (P < .05) for wk 1 through 4, and were heavier (P < .01) than those in CR-50 groups at the end of wk 4 (3%) and 9 (4%). Pigs in L groups had a greater within-pen coefficient of variation in BW at the end of wk 9 than pigs in S groups. Large groups and reduced floor-space allowance reduced piglet growth performance in the nursery.

Characterization of devH, a gene encoding a putative DNA binding protein required for heterocyst function in Anabaena sp. strain PCC 7120

The devH gene was identified in a screen for Anabaena sp. strain PCC 7120 sequences whose transcripts increase in abundance during a heterocyst development time course. The product of devH contains a helix-turn-helix motif similar to the DNA binding domain of members of the cyclic AMP receptor protein family, and the protein is most closely related to the cyanobacterial transcriptional activator NtcA. devH transcripts are barely detectable in vegetative cells and are induced approximately fivefold after nitrogen starvation. This induction is absent in the two developmental mutants hetR and ntcA. The gene is expressed as monocistronic transcripts with multiple 5' termini, and the approximately 500-bp region 5' to devH was shown to have promoter activity in vivo. The devH gene was insertionally inactivated by the integration of plasmid sequences within the open reading frame. Nitrogen starvation of the devH mutant induces heterocysts of wild-type morphology, but the mutant is inviable in the absence of fixed nitrogen and unable to reduce acetylene aerobically.

Endothelial modulation of neural sympathetic vascular tone in canine skeletal muscle

The effect of nitric oxide synthase (NOS) inhibition and endothelin-A (ETA)-receptor blockade on neural sympathetic control of vascular tone in the gastrocnemius muscle was examined in anesthetized dogs under conditions of constant flow. Muscle perfusion pressure (MPP) was measured before and after NOS inhibition (Nomega-nitro-L-arginine methyl ester; L-NAME) and ETA-receptor blockade [cyclo-(D-Trp-d-Asp-Pro-D-Val-Leu); BQ-123]. Zero and maximum sympathetic nerve activities were achieved by sciatic nerve cold block and stimulation, respectively. In group 1 (n = 6), MPP was measured 1) before nerve cold block, 2) during nerve cold block, and 3) during nerve stimulation. Measurements under these conditions were repeated after L-NAME and then BQ-123. The same protocol was followed in group 2 (n = 6) except that the order of L-NAME and BQ-123 was reversed. MPP and muscle vascular resistance (MVR) increased after L-NAME and then decreased to control values after BQ-123. MVR decreased after BQ-123 alone and, with the addition of L-NAME, increased to a level not different from that observed during the control period. MVR fell during nerve cold block. This response was not affected by administration of L-NAME followed by BQ-123, but it was attenuated by administration of BQ-123 before L-NAME. The constrictor response during sympathetic nerve stimulation was enhanced by L-NAME; no further effect was observed with BQ-123, nor was the response affected when BQ-123 was given first. These findings indicate that endothelin contributes to 1) basal vascular tone in skeletal muscle and 2) the increase in skeletal muscle vascular resistance after NOS inhibition. Finally, nitric oxide "buffers" the degree of constriction in skeletal muscle vasculature during maximal sympathetic stimulation.

Toppled television sets cause significant pediatric morbidity and mortality

OBJECTIVE

To quantify pediatric injuries and deaths that result from toppled television sets.

DESIGN

Retrospective analysis of incident files compiled by the US Consumer Product Safety Commission (CPSC) data systems and The Children's Hospital of Alabama (TCHA) inpatient medical records.

SETTING

United States, January 1990-June 1997. TCHA, May 1995-October 1997.

MAIN OUTCOME MEASURES

Morbidity or mortality as a result of a television set falling onto a child.

RESULTS

Over the 7-year period from January 1990 to June 1997, 73 cases that involved falling television sets were reported to the CPSC, including 28 deaths. The mean age of all victims was 36 months (SD +/- 25.4 months). The mean age of those who died was 31 months (SD +/- 22 months). Females accounted for 42 incidents (58%) and 19 deaths (68%). The most common anatomic site of injury was the head, which accounted for 72% of cases investigated by CPSC personnel. Of the 14 deaths further investigated by the CPSC, head injury was responsible for 13, with a generalized crushing injury accounting for the other. Of the 45 cases in which data were available, dressers or stands were identified as the television support 76% of the time. The TCHA database yielded five additional cases, including one death, with demographics similar to the CPSC data.

CONCLUSION

Serious injury and death can occur as a result of children toppling television sets from elevated locations in the home. The furniture on which a television set is situated is of fundamental importance. An estimate of overall risk to the population is impossible to determine from these data. In light of 73 reported cases with 28 deaths; however, injury prevention counseling and other strategies supporting in-home safety should include a secure and child-safe location for television sets. Attention should be paid to safer design and placement of this ubiquitous product. television, wounds and injuries, accidents, human, infants, children.

Raising P50 increases tissue PO2 in canine skeletal muscle but does not affect critical O2 extraction ratio

Affinity of hemoglobin (Hb) for O2 determines in part the rate of O2 diffusion from capillaries to myocytes by altering capillary PO2. We hypothesized that a decrease in Hb O2 affinity (increased P50) would increase capillary and tissue PO2 (PtiO2) and improve O2 consumption during ischemia. To test this hypothesis, blood flow to the pump-perfused left hindlimb of 18 anesthetized and paralyzed dogs was progressively decreased over 90 min while hindlimb O2 consumption and O2 delivery (QO2) and PtiO2 were measured at the muscle surface. Arterial PO2 was maintained at 150 +/- 10 Torr in all dogs. We increased P50 by 12.3 +/- 0.9 (SE) Torr in nine dogs with RSR-13, an allosteric modifier of Hb. This decreased arterial O2 saturation to 90-92% but increased mean PtiO2 from 35.5 +/- 11.6 to 44.1 +/- 15.2 (SD) Torr (P < 0.05) with no change in controls (n = 9). O2 extraction ratio at critical QO2 was 74 +/- 2% in controls and 79 +/- 1% in RSR-13-treated dogs (P = not significant). PtiO2 was 30-40% higher in the RSR-13-treated group at any QO2 above critical but did not differ between groups below critical QO2. Perfusion heterogeneity and convergence of the dissociation curves near critical QO2 may have mitigated any effect of increased P50 on O2 diffusion. Still, increasing P50 by 12 Torr with RSR-13 significantly increased PtiO2 at QO2 values above critical.

ATP-sensitive K+ channel blockade impairs O2 extraction during progressive ischemia in pig hindlimb

Tissues maintain O2 consumption (VO2) when blood flow and O2 delivery (DO2) are decreased by better matching of blood flow to meet local cellular O2 demand, a process that increases extraction of available O2. This study tested the hypothesis that ATP-sensitive K+ channels play a significant role in the response of pig hindlimb to ischemia. We pump perfused the vascularly isolated but innervated right hindlimb of 14 anesthetized pigs with normoxic blood while measuring hindlimb DO2, VO2, perfusion pressure, and cytochrome aa3 redox state. In one-half of the pigs, the pump-perfused hindlimb was also infused with 10 micrograms.min-1.kg-1 of glibenclamide, a potent blocker of ATP-sensitive K+ channels. Control animals were infused with 5% glucose solution alone. Blood flow was then progressively reduced in both groups in 10 steps at 10-min intervals. Glibenclamide had no effect on any preischemic hindlimb or systemic measurements. Hindlimb VO2 and cytochrome aa3 redox state began to decrease at a significantly higher DO2 in glibenclamide-treated compared with control pigs. At this critical DO2, the O2 extraction ratio (VO2/DO2) was 53 +/- 4% in the glibenclamide group and 73 +/- 5% in the control group (P < 0.05). Hindlimb vascular resistance increased significantly with ischemia in the glibenclamide group but did not change in the control group. We conclude that ATP-sensitive K+ channels may be importantly involved in the vascular recruitment response that tried to meet tissue O2 needs as blood flow was progressively reduced in the pig hindlimb.

Effects of nitric oxide synthase inhibition on regional hemodynamics and oxygen transport in endotoxic dogs

Nitric oxide synthase (NOS) inhibition has been used to increase blood pressure in humans with septic shock despite a lack of data regarding its effects on O2 delivery (QO2). We studied the effects of NG-nitro-L-arginine methyl ester (L-NAME) on systemic, gut, and hindlimb circulations of endotoxic dogs. Twelve dogs were infused with 2 mg/kg of LPS over 1 h followed by 60 mL/kg of 6% dextran over 2 h. Six dogs also received 20 mg/kg of L-NAME, LPS caused mean arterial pressure (MAP), flow and QO2 to whole body, hindlimb and gut to decrease, but O2 uptake (VO2) did not change. Dextran resuscitation alone produced a hyperdynamic state with increased blood flow to or above baseline. With L-NAME, systemic and regional resistances increased twofold and MAP returned to near baseline. Late in the study, these dogs had significantly lower blood flow and QO2 to the gut but maintained VO2 by increasing oxygen extraction to near critical levels. These data suggest that in acute endotoxicosis, L-NAME may significantly improve blood pressure but may markedly encroach on O2 transport reserves to the gut.

Role of the vascular endothelium in O2 extraction during progressive ischemia in canine skeletal muscle

O2 extraction during progressive ischemia in canine skeletal muscle, J. Appl. Physiol. 79(4): 1351-1360, 1995.--O2 uptake (VO2) is defended during decreased O2 delivery (QO2) by an increase in the O2 extraction ratio (O2ER, VO2/QO2), presumably by recruitment of capillaries. This study tested the hypothesis that activity of the microvascular endothelium plays a necessary role in achievement of maximal O2ER. We pump perfused the vascularly isolated hindlimbs of 24 anesthetized and paralyzed dogs at progressively lower flows over a 90-min period. In eight dogs, hindlimb vascular endothelium was removed by injection of deoxycholate (DOC) into the perfusing artery before the ischemic challenge. DOC treatment resulted in loss of normal in vivo and in vitro endothelium-dependent dilatory responses to acetylcholine, but endothelium-independent vascular smooth muscle responses were intact. Eight other dogs were pretreated with nitro-L-arginine methyl ester plus indomethacin (L+I group) to block the synthesis of the vasodilators nitric oxide and prostacyclin. L+I and DOC treatment were associated with increases in hindlimb vascular resistance of 168 +/- 17 and 63 +/- 12%, respectively. O2ER at critical QO2 (QO2 at which VO2 begins to decrease) was 81 +/- 2% in eight control dogs, 66 +/- 6% in L+I, and 42 +/- 4% in DOC, indicating a significant O2 extraction defect in the two treatment groups. These data suggest that products of the vascular endothelium play an important role in the matching of O2 supply to demand during supply limitation in skeletal muscle.

Role of endothelial factors in active hyperemic responses in contracting canine muscle

We investigated whether endothelium-derived relaxing factor (EDRF) and prostaglandins, which may be released under conditions of increased blood flow, contribute to the active hyperemia in contracting muscle of anesthetized dogs. The venous outflow from the left gastrocnemius muscle was isolated and measured. The tendon was cut and placed in a force transducer. One group served as a control (Con; n = 9); EDRF synthesis was inhibited using N omega-nitro-L-arginine methyl ester (L-NAME) in a second group (n = 9), and a third group (n = 7) received L-NAME and indomethacin (L-NAME+Indo) to inhibit prostaglandin synthesis. After resting measurements, the distal end of the cut sciatic nerve was stimulated to produce isometric contractions at 1, 2, 4, and 6 twitches/s for 6-8 min, separated by 25-min recovery periods. Blood flow and O2 uptake increased linearly from resting values of 11.8 +/- 2.4 and 0.3 +/- 0.05 ml.100 g-1.min-1, respectively, to maximal values of 84.2 +/- 5.1 and 11.1 +/- 0.7 ml.100 g-1.min-1 in the Con group; neither these values nor those for tension development were different from values observed at comparable contraction frequencies in the L-NAME and L-NAME+Indo groups. At rest, resistance was greater (P < 0.05) in both the L-NAME and L-NAME+Indo groups compared with Con, the highest value (P < 0.05) occurring in the L-NAME+Indo group. Muscle resistance decreased (P < 0.05) in all groups at all contraction frequencies; the values were not different among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypoxic vasodilation does not require nitric oxide (EDRF/NO) synthesis

Our question was whether inhibition of nitric oxide [endothelium-derived relaxing factor (EDRF)/NO] production in an in situ vascularly isolated but innervated canine hindlimb would prevent hypoxic vasodilation or interfere with O2 extraction during ischemic (IH) or hypoxic hypoxia (HH). After a control period, we gave NG-nitro-L-arginine methyl ester (L-NAME, 20 mg/kg i.v.) to two of four groups of six dogs before a 30-min period of IH or HH. In IH, arterial inflow from a pump-membrane oxygenator system was lowered from 65 to 35 ml.min-1.kg-1 with PO2 maintained at approximately 110 Torr. In HH, PO2 was lowered from 107 to 28 Torr with flow at 78 ml.min-1.kg-1. Total O2 delivery was lowered to approximately 5 ml.min-1.kg-1 in all groups during hypoxia. Hindlimb vascular resistance (LVR) increased from 1.11 +/- 0.09 to 2.21 +/- 0.25 peripheral resistance units (PRU; P < 0.05) after L-NAME infusion and hindlimb O2 uptake increased from 3.9 +/- 0.2 to 4.5 +/- 0.3 ml.min-1.kg-1 (P < 0.05). In controls, LVR decreased from 1.10 +/- 0.06 to 0.63 +/- 0.04 PRU with HH (P < 0.05) and from 1.03 +/- 0.06 to 0.82 +/- 0.02 PRU (P = NS) with IH. In L-NAME-treated dogs, LVR decreased from 2.38 +/- 0.37 to 1.07 +/- 0.13 PRU with HH (P < 0.05) and from 2.04 +/- 0.29 to 1.41 +/- 0.13 PRU (P = NS) with IH. There were no differences in O2 extraction ratio (0.72) or in O2 uptake between groups during hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

Canine hindlimb blood flow and O2 uptake after inhibition of EDRF/NO synthesis

The nitric oxide synthase (NOS) inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) was used to determine whether the decrease in canine hindlimb blood flow (QL) with NOS inhibition would limit skeletal muscle O2 uptake (VO2). Arterial inflow and venous outflow from the hindlimb were isolated, and the paw was excluded from the circulation. Pump perfusion from the right femoral artery kept the hindlimb perfusion pressure near the auto-perfused level. Six anesthetized dogs received L-NAME (20 mg/kg i.v.), whereas another group of five dogs received the stereospecific enantiomer N omega-nitro-D-arginine methyl ester (D-NAME 20 mg/kg i.v.). Efficacy of NOS inhibition was tested with intra-arterial boluses of acetylcholine. QL was measured continuously, and whole body and hindlimb VO2 were measured 60 and 120 min after L-NAME or D-NAME. Whole body VO2 remained at control levels, but cardiac output decreased from 117 +/- 17 to 57 +/- 7 ml.kg-1.min-1 60 min after L-NAME (P < 0.05) and remained at that level for the duration of the experiment. Cardiac output was significantly higher in the D-NAME group than in the L-NAME group at 60 min. After L-NAME, QL fell 24% but VO2 increased from 5.2 +/- 0.4 to 7.4 +/- 0.6 ml.kg-1.min-1 (P < 0.05). No change in QL or VO2 occurred after D-NAME. NOS inhibition did not limit hindlimb VO2, despite decreases in blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Gut and muscle tissue PO2 in endotoxemic dogs during shock and resuscitation

There is indirect evidence that tissue hypoxia occurs in human sepsis and surface measures of muscle tissue PO2 (PtiO2) in hypodynamic endotoxic animals are decreased. This study assessed systemic and regional tissue oxygenation in a more relevant model of hyperdynamic endotoxicosis. We isolated venous outflow from the left hindlimb and a segment of ileum in six anesthetized dogs to measure muscle and gut O2 delivery and uptake (VO2) and lactate flux, gut intramucosal pH (pHi) by tonometry, and PtiO2 by multi-point surface electrodes placed on mucosal and serosal surfaces of gut and on muscle. We then infused Escherichia coli lipopolysaccharide (LPS; 2 mg/kg) over 1 h followed by a 2-h infusion of dextran (0.5 ml.kg-1.min-1). LPS infusion significantly decreased systemic and gut VO2, cardiac output (Q), and blood pressure and increased arterial lactate and gut lactate flux. Resuscitation increased Q to above baseline and restored systemic VO2. In response to LPS and then resuscitation, muscle PtiO2 distribution did not change, suggesting little microcirculatory disturbance, although mean PtiO2 first decreased and then increased. In contrast, gut VO2 and pHi remained low and lactate output remained high, despite restoration of gut blood flow. Gut VO2, lactate flux, pHi, and PtiO2 histograms were consistent with a marked redistribution of blood flow within the gut wall, away from the mucosa and toward the muscularis. These data show that, in hyperdynamic acute endotoxemia, skeletal muscle PtiO2 and VO2 are well maintained, but blood flow within the gut is significantly disturbed with mucosal hypoxia.