Effects of solar UV radiation and climate change on biogeochemical cycling: interactions and feedbacks.

Solar UV radiation, climate and other drivers of global change are undergoing significant changes and models forecast that these changes will continue for the remainder of this century. Here we assess the effects of solar UV radiation on biogeochemical cycles and the interactions of these effects with climate change, including feedbacks on climate. Such interactions occur in both terrestrial and aquatic ecosystems. While there is significant uncertainty in the quantification of these effects, they could accelerate the rate of atmospheric CO(2) increase and subsequent climate change beyond current predictions. The effects of predicted changes in climate and solar UV radiation on carbon cycling in terrestrial and aquatic ecosystems are expected to vary significantly between regions. The balance of positive and negative effects on terrestrial carbon cycling remains uncertain, but the interactions between UV radiation and climate change are likely to contribute to decreasing sink strength in many oceanic regions. Interactions between climate and solar UV radiation will affect cycling of elements other than carbon, and so will influence the concentration of greenhouse and ozone-depleting gases. For example, increases in oxygen-deficient regions of the ocean caused by climate change are projected to enhance the emissions of nitrous oxide, an important greenhouse and ozone-depleting gas. Future changes in UV-induced transformations of aquatic and terrestrial contaminants could have both beneficial and adverse effects. Taken in total, it is clear that the future changes in UV radiation coupled with human-caused global change will have large impacts on biogeochemical cycles at local, regional and global scales.

Does the type of CIA policy significantly affect bar and restaurant employment in Minnesota cities?

Clean indoor air (CIA) policies that include free-standing bars and restaurants have been adopted by communities to protect employees in all workplaces from exposure to environmental tobacco smoke, most notably employees working in restaurants and free-standing bars. However, due to the perception of negative economic effects on alcohol-licensed hospitality businesses, partial CIA policies (those that provide an exemption for free-standing bars) have been proposed as a means to reduce the risk of economic effects of comprehensive CIA policies applied to all worksites. Bar and restaurant employment per capita were used to determine if partial CIA policies produced differential economic effects compared to comprehensive CIA policies. Ten cities in the state of Minnesota were studied from 2003-2006. Economic data were drawn from monthly employment in bars and restaurants, and a pooled time-series was completed to evaluate three types of local CIA policies: Comprehensive, partial, or none beyond the state law. Communities with a comprehensive CIA policy had a decrease of 9 employees per 10,000 residents compared with communities with partial CIA policies (p = 0.10). Communities with any type of CIA policy (partial or comprehensive) had an increase of 3 employees per 10,000 residents compared to communities without any CIA policies (p = 0.36). There were no significant differential economic effects by CIA policy type in Minnesota cities. These findings support the adoption of comprehensive CIA policies to provide all employees protection from environmental tobacco smoke exposure.

The relationship between local clean indoor air policies and smoking behaviours in Minnesota youth.

BACKGROUND: While clean indoor air (CIA) policies are intended to reduce exposure to second-hand smoke in the workplace, restrictions in public workplaces have the potential to discourage youth smoking. There is growing evidence from cross-sectional and ecological studies, but limited evidence from longitudinal studies that this is so. OBJECTIVE: To evaluate the association between local CIA policies and smoking behaviours among Minnesota youth over time. DESIGN, SETTING AND SUBJECTS: A cohort of 4233 Minnesota youths, ages 11 to 16 at baseline, was interviewed via telephone for 6 years (2000-2006). Individual, family and community level variables were collected from participants every 6 months. A generalised estimating equation (GEE) logistic regression was used to assess the relationship between CIA policies and past-month smoking in youth over time. The analysis was controlled for potential confounders at individual and community levels. RESULTS: There was not significant association between CIA policies and youth smoking behaviours in the multivariate analyses. At the individual level, parental smoking significantly increased the odds of smoking nearly 40% and close friend smoking increased the odds of past-month smoking by nearly 100% for each close friend. Banning smoking in the home was significantly associated with a 12% reduction in the odds of past-month smoking. CONCLUSION: After accounting for other community and individual level factors known to be associated with youth smoking, there was no significant association between CIA policies and past-month smoking for youth over time.

Interactive effects of solar UV radiation and climate change on biogeochemical cycling.

This report assesses research on the interactions of UV radiation (280-400 nm) and global climate change with global biogeochemical cycles at the Earth's surface. The effects of UV-B (280-315 nm), which are dependent on the stratospheric ozone layer, on biogeochemical cycles are often linked to concurrent exposure to UV-A radiation (315-400 nm), which is influenced by global climate change. These interactions involving UV radiation (the combination of UV-B and UV-A) are central to the prediction and evaluation of future Earth environmental conditions. There is increasing evidence that elevated UV-B radiation has significant effects on the terrestrial biosphere with implications for the cycling of carbon, nitrogen and other elements. The cycling of carbon and inorganic nutrients such as nitrogen can be affected by UV-B-mediated changes in communities of soil organisms, probably due to the effects of UV-B radiation on plant root exudation and/or the chemistry of dead plant material falling to the soil. In arid environments direct photodegradation can play a major role in the decay of plant litter, and UV-B radiation is responsible for a significant part of this photodegradation. UV-B radiation strongly influences aquatic carbon, nitrogen, sulfur and metals cycling that affect a wide range of life processes. UV-B radiation changes the biological availability of dissolved organic matter to microorganisms, and accelerates its transformation into dissolved inorganic carbon and nitrogen, including carbon dioxide and ammonium. The coloured part of dissolved organic matter (CDOM) controls the penetration of UV radiation into water bodies, but CDOM is also photodegraded by solar UV radiation. Changes in CDOM influence the penetration of UV radiation into water bodies with major consequences for aquatic biogeochemical processes. Changes in aquatic primary productivity and decomposition due to climate-related changes in circulation and nutrient supply occur concurrently with exposure to increased UV-B radiation, and have synergistic effects on the penetration of light into aquatic ecosystems. Future changes in climate will enhance stratification of lakes and the ocean, which will intensify photodegradation of CDOM by UV radiation. The resultant increase in the transparency of water bodies may increase UV-B effects on aquatic biogeochemistry in the surface layer. Changing solar UV radiation and climate also interact to influence exchanges of trace gases, such as halocarbons (e.g., methyl bromide) which influence ozone depletion, and sulfur gases (e.g., dimethylsulfide) that oxidize to produce sulfate aerosols that cool the marine atmosphere. UV radiation affects the biological availability of iron, copper and other trace metals in aquatic environments thus potentially affecting metal toxicity and the growth of phytoplankton and other microorganisms that are involved in carbon and nitrogen cycling. Future changes in ecosystem distribution due to alterations in the physical and chemical climate interact with ozone-modulated changes in UV-B radiation. These interactions between the effects of climate change and UV-B radiation on biogeochemical cycles in terrestrial and aquatic systems may partially offset the beneficial effects of an ozone recovery.

Therapeutic electrical stimulation of the hypoglossal nerve in obstructive sleep apnea.

BACKGROUND: Hypoglossal nerve stimulation has been demonstrated to relieve upper airway obstruction acutely, but its effect on obstructive sleep apnea is not known. OBJECTIVE: To determine the response in obstructive sleep apnea to electrical stimulation of the hypoglossal nerve. METHODS: Eight patients with obstructive sleep apnea were implanted with a device that stimulated the hypoglossal nerve unilaterally during inspiration. Sleep and breathing patterns were examined at baseline before implantation and after implantation at 1, 3, and 6 months and last follow-up. RESULTS: Unilateral hypoglossal nerve stimulation decreased the severity of obstructive sleep apnea throughout the entire study period. Specifically, stimulation significantly reduced the mean apnea-hypopnea indices in non-rapid eye movement (mean +/- SD episodes per hour, 52.0 +/- 20.4 for baseline nights and 22.6 +/- 12.1 for stimulation nights; P<.001) and rapid eye movement (48.2 +/- 30.5 and 16.6 +/- 17.1, respectively; P<.001) sleep and reduced the severity of oxyhemoglobin desaturations. With improvement in sleep apnea, a trend toward deeper stages of non-rapid eye movement sleep was observed. Moreover, all patients tolerated long-term stimulation at night and did not experience any adverse effects from stimulation. Even after completing the study protocol, the 3 patients who remained free from stimulator malfunction continued to use this device as primary treatment. CONCLUSION: The findings demonstrate the feasibility and therapeutic potential for hypoglossal nerve stimulation in obstructive sleep apnea.

Posttraumatic stress disorder and depression symptomatology in a sample of Gulf War veterans: a prospective analysis.

The authors examined the relationship over time of posttraumatic stress disorder (PTSD) and depression symptoms in a sample of Gulf War veterans. A large sample (N = 2,949) of Gulf War veterans was assessed immediately following their return from the Gulf region and 18-24 months later. Participants completed a number of self-report questionnaires including the Mississippi Scale for Combat-Related PTSD (T. M. Keane, J. M. Caddell, & K. L. Taylor, 1988) and the Brief Symptom Inventory (L. R. Derogatis & N. Melisaratos, 1983) at both time points and an extended and updated version of the Laufer Combat Scale (M. Gallops, R. S. Laufer, & T. Yager, 1981) at the initial assessment. A latent-variable, cross-lag panel model found evidence for a reciprocal relation between PTSD and Depression. Follow-up models examining reexperiencing, avoidance-numbing, and hyperarousal symptoms separately showed that for reexperiencing and avoidance-numbing symptoms, the overall reciprocal relation held. For hyperarousal symptoms, however, the association was from early hyperarousal to later depression symptoms only.

Coping with Gulf War combat stress: mediating and moderating effects.

The authors examined relationships between method of coping with combat-related stress and psychological symptoms among Gulf War Army personnel (N = 1,058). Participants were surveyed on return from the Gulf region (Time 1) with the Coping Responses Inventory (R. Moos, 1990) and a measure of combat exposure. Outcomes were symptom measures of posttraumatic stress disorder (PTSD) and depression. At Time 2 (18-24 months) participants completed the same symptom measures and an index of postwar stress. Higher proportions of approach-based coping in the war zone were related to lower levels of psychological symptoms. Combat exposure moderated the effects of coping on Time 1 PTSD. Coping predicted changes in symptoms of depression but not PTSD. Combat exposure affected changes in depression through postwar stress but had a direct negative effect on PTSD.

An investigation of the impact of posttraumatic stress disorder on physical health.

In a large sample of Gulf War veterans (N = 2301) we examined the relations between PTSD symptoms assessed immediately upon returning from the Gulf War and self-reported health problems assessed 18-24 months later. PTSD symptomatology was predictive of self-reported health problems over time for both men and women veterans, even after the effects of combat exposure were removed from the analysis. Female veterans reported significantly more health problems than male veterans, however, there was no interactive effect of gender and PTSD on health problems. These findings provide further support for the theory that psychological response to stressors impacts health outcome.

Posttraumatic stress disorder and retrospectively reported stressor exposure: a longitudinal prediction model.

There has been recent concern about the degree to which posttraumatic stress disorder (PTSD) symptomatology influences reports of prior exposure to highly stressful life events. In this longitudinal study of 2,942 male and female Gulf War veterans, the authors documented change in stressor reporting across 2 occasions and the association between change and PTSD symptom severity. A regression-based cross-lagged analysis was used to examine the relationship between PTSD symptom severity and later reported stressor exposure. Shifts in reporting over time were modestly associated with PTSD symptom severity. The cross-lagged analysis revealed a marginal association between Time 1 PTSD symptom severity and Time 2 reported stressor exposure for men and suggested that later reports of stressor exposure are primarily accounted for by earlier reports and less so by earlier PTSD symptomatology.

Course and predictors of posttraumatic stress disorder among Gulf War veterans: a prospective analysis.

Rates and predictors of posttraumatic stress disorder (PTSD) over time are not well understood. This study is the first to look at the rates of PTSD immediately following war and 2 years later using a large cohort (N = 2,949) of Gulf War veterans. Using a cut score to indicate presumptive PTSD, 3% of participants exceeded the cutoff at Time 1 compared with 8% at Time 2. Those who exceeded the cutpoint at Time 1 were up to 20 times more likely to exceed the cutpoint at Time 2 than those who did not exceed the cutpoint at Time 1. Women and those with high levels of combat exposure were at increased risk for PTSD at both times. Being young, being single, and having previous combat experience were associated with increased risk at Time 1 only, whereas reservists and enlisted personnel were at increased risk at Time 2 only. These findings indicate that, although low initially, rates of PTSD increased substantially over time.

Relationship of psychiatric status to Gulf War veterans' health problems.

OBJECTIVE: A growing body of research has shown that there are important links between certain psychiatric disorders and health symptom reporting. Two disorders in particular (posttraumatic stress disorder (PTSD) and major depression) have been the most widely implicated to date, and this association has sometimes been used to explain the occurrence of ill-defined medical problems and increased somatic symptoms in certain groups, most recently Gulf War veterans. METHODS: Structured psychiatric diagnostic interviews were used to examine the presence of major psychiatric (axis I) disorders and their relation to health symptom reporting in a well-characterized, stratified subset of Gulf War veterans and a non-Gulf-deployed veteran comparison group. RESULTS: Rates of most psychiatric disorders were substantially lower than national comorbidity estimates, consistent with prior studies showing heightened physical and emotional well-being among active-duty military personnel. Rates of PTSD and major depression, however, were significantly elevated relative to the veteran comparison group. The diagnosis of PTSD showed a small but significant association with increased health symptom reports. However, nearly two-thirds of Gulf participants reporting moderate to high health symptoms had no axis I psychiatric diagnosis. CONCLUSIONS: Results suggest that rates of psychiatric illness were generally low with the exception of PTSD and major depression. Although PTSD was associated with higher rates of reported health problems, this disorder did not entirely account for symptoms reported by participants. Factors other than psychiatric status may play a role in Gulf War health problems.

Prospective analysis of the relation between DSM-III anxiety disorders and alcohol use disorders.

OBJECTIVE: Cross-sectional studies show a robust association between anxiety disorders and alcohol use disorders (comorbidity); however, this methodology does not allow for the testing of causal models. The authors attempted to overcome this limitation by examining comorbid relationships prospectively. METHOD: Male and female college students were assessed as freshmen (year 1), and then again at years 4 and 7, for selected 12-month anxiety disorders (generalized anxiety disorder, agoraphobia, and social phobia or panic) diagnosed according to the National Institute of Mental Health Diagnostic Interview Schedule (DIS) and DSM-III and for 12-month DIS/DSM-III alcohol use disorders (alcohol dependence alone and alcohol abuse or dependence). RESULTS: Cross-sectionally, the odds of having either an anxiety disorder or an alcohol use disorder were two- to fivefold greater when the other condition was present. Prospectively, the odds of developing a new alcohol dependence diagnosis at year 7 increased from 3.5 to five times for those diagnosed with an anxiety disorder at years 1 or 4. Conversely, the odds of developing a new anxiety disorder at year 7 increased by about four times for those diagnosed with alcohol dependence at years 1 or 4. When alcohol abuse and dependence were combined, the pattern of findings was similar, albeit weaker. Multivariate path models provide similar results and highlight the reciprocal influence of alcohol use disorders and anxiety disorders. CONCLUSIONS: Alcohol use disorders (especially alcohol dependence) and anxiety disorders demonstrate a reciprocal causal relationship over time, with anxiety disorders leading to alcohol dependence and vice versa.

Predicting academic problems in college from freshman alcohol involvement.

OBJECTIVE: The present article examines the relation of problematic alcohol use to collegiate academic problems based on a systematic assessment of problematic alcohol use and college transcript data. The degree to which this prospective association can be explained by reference to third variables is also explored. These third variables include: students' high school academic achievement and aptitude, concurrent drug use, participation in deviant behaviors and students' investment or participation in the college experience. METHOD: A sample of 444 (240 female) college freshman recruited for a longitudinal study of alcohol use was followed for 6 years. Alcohol and drug involvement, general deviance, academic investment, campus involvement and several background variables were assessed during the freshman year. Additional measures of high school aptitude and achievement as well as collegiate performance were calculated based on college transcript data from all institutions attended. RESULTS: A latent variable structural equation model revealed that problematic alcohol use during the freshman year correlated +.32 with collegiate academic problems. No evidence was found for a unique association between the two constructs when additional constructs were included in the model. Specifically, the association was substantially reduced when preexisting student differences traditionally associated with academic failure in college were taken into account. The inclusion of concurrent drug use and deviance also resulted in a significant reduction in the magnitude of the association. CONCLUSIONS: Although a substantial bivariate association exists between problematic alcohol use and academic problems during college, much of this association appears attributable to preexisting student differences on admission to college.

A prospective, high-risk study of the relationship between tobacco dependence and alcohol use disorders.

This study examined the extent to which tobacco dependence (TD) and alcohol use disorders (AUDs) reciprocally influenced each other in a mixed-gender sample of 452 individuals (n = 232 biological family history of paternal alcoholism, n = 220 no first- or second-degree family history of alcoholism) who were assessed once early in their freshman year of college, approximately 3 years later when many were college seniors, and approximately 3 years later when many had entered or were entering the work force. AUDs were more prevalent in men than women, in individuals with a family history of alcoholism, and decreased overall with time. TD was more prevalent in those with a family history of alcoholism, showed increasing rates of use over time, and was less prevalent but more stable than AUDs. Transitional probabilities indicated that although a previous AUD or TD diagnosis increased the likelihood of being diagnosed with the other disorder at a later time, comorbid AUDs and TD did not significantly affect the likelihood of recovery from either disorder. Finally, path analysis revealed significant reciprocal relationships between AUDs and TD diagnoses (each predicting the other over time), and significant prediction of AUDs and TD by family history of alcoholism at the first and third times of assessment. Findings supported two general models of AUD/TD comorbidity: a shared vulnerability model and a reciprocal influence model.

Myelolipoma of the adrenal gland: a case report.

Adrenal myelolipomas are rare benign neoplasms composed of mature fat and bone marrow elements. Most are asymptomatic tumors found incidentally at postmortem examinations. We report the natural history of an adrenal myelolipoma in a middle-aged man over a 6-year interval.

Primary carcinoid tumor of the testis.

We have presented a case of primary testicular carcinoid in an otherwise asymptomatic 50-year-old white man treated by right orchiectomy; a postoperative abdominal CT scan was normal. Histologically and cytologically the tumor resembled carcinoids of midgut origin. Most primary testicular carcinoid tumors are not clinically functional, and thus the diagnosis is not suspected preoperatively.

Exercise for the Older Adult.

Exercise at my age? This report provides ammunition to help physicians convince themselves and their patients that exercise for the older adult is healthy and necessary.