Stimulation of the proximal tubule Na+-ATPase activity by adenosine A(2A) receptor

The aim of this work was to determine the molecular mechanism involved in the stimulation of the pig kidney proximal tubule Na+-ATPase by adenosine (Ado). To study the role of A2 Ado receptors, we added in all experiments 10(-6)M DPCPX, an A1 receptor-selective antagonist, since we have previously shown that Ado inhibits the enzyme activity through this receptor. Ado increased the Na+-ATPase activity with maximal effect observed at 10(-6)M. The presence of both A(2A) and A(2B) receptors were demonstrated by immunoblotting using specific polyclonal antibodies. The stimulatory effect of Ado was completely abolished by 5 x 10(-9)M DMPX, an antagonist of A2 receptor, and 10(-7)M SCH 58261, an A(2A) receptor-selective antagonist. DMPA (10(-7)M), a specific agonist of A(2A) receptor mimicked the stimulatory effect of Ado. Involvement of a Gs protein/adenylate cyclase/PKA pathway was evidenced by: (a) the reversion of Ado-induced effect by GDPbetaS; (b) stimulation of the Na+-ATPase activity in a similar and non-additive manner to Ado by 10(-8)M cholera toxin, 10(-7)M GTPgammaS, 10(-6)M forskolin, 10(-7)M cAMP or 1.25 U catalytic subunit of PKA; (c) the reversion of the stimulatory effect of Ado by 10(-8)M PKA inhibitor peptide; (d) Ado-produced two-fold increase of the PKA activity, which was completely reversed by 10(-6)M DMPX. These are the first evidences showing the modulation of a renal primary active sodium transporter by Ado through A(2A) receptor.

Using verbal autopsy to identify and proportionally assign cause of death in Ibadan, southwest Nigeria

Reliable and accurate data remain scarce on the cause and rates of mortality among adults in sub-Saharan Africa. The Idikan Adult Mortality Study, a prospective community-based study was initiated in order to obtain the overall as well as cause-specific mortality data for a community of adults (15 years and above). Standardised verbal autopsy questionnaire was used to investigate and assign the mode and cause of death. There were 232 reported deaths in the baseline population of 4127 adults over 5 years, giving an unadjusted death rate of 11.2 per 1000 per year. Thirty-nine (16.8% ) of these death occurred suddenly. The commonest known cause of death was due to cardiovascular disease, which was responsible for 43 (18.5% ) of all deaths. It was also the commonest known cause of sudden death accounting for 30.8% of such deaths. Infection was responsible for 28 (12.1% ) deaths while injury accounted for 7 (2.6% ) deaths. Subjects, 50 years and above were more likely to die and also die suddenly than were the younger subject (p<0.0001, p<0.0001) and significantly more death occurred in males than females (6.9% versus 4.7% ) (P<0.01). Deaths were also more likely to have occurred at home and outside the hospital, increasing the probability of these deaths being underreported. Following multivariate logistic regression analysis, respondents between the age of 20 -49 years had significantly reduced risk of dying (p=0.029), while cigarette smoking significantly increased the risk of dying (p=0.012). In the absence of the urgently needed vital statistics, use of verbal autopsies is a potentially useful investigative method for identifying and assigning cause of adult deaths in a community.

Co-ordination within and between verbal and visuospatial working memory: network modulation and anterior frontal recruitment

Attention switching between items being stored and manipulated in working memory (WM) is proposed to be an elementary executive function. Experiment 1 reveals a similar attentional limitation within and between verbal and visuospatial WM and identifies a supramodal switching process required for switching between WM items. By using functional magnetic resonance imaging, Experiment 2 investigated brain activation correlates of parametrically varied attention switching within and between these two WM modalities. Attention switching activation was broadly distributed, was quite similar across the three conditions, and, in almost all areas, increased with increasing switching demand, indicating that attention switching recruits and modulates the entire WM network. Dorsolateral prefrontal cortex was implicated in both within- and between-modality attention switching, but no significant activation was found in ventrolateral areas, supporting dorsal-ventral process models of prefrontal organization. A functional dissociation between anterior frontal and dorsolateral prefrontal cortex was found with the former being more activated when switching attention between modalities was required. The data challenge the notion of an anatomically separate attention switching executive function, but suggest that anterior frontal areas are recruited for the additional demand of coordinating the verbal and visuospatial WM slave systems.

Measurement of offline exhaled nitric oxide in a study of community exposure to air pollution

As part of a large panel study in Seattle, Washington, we measured levels of exhaled nitric oxide (eNO) in children's homes and fixed-site particulate matter with aerodynamic diameters of 2.5 micro m or less (PM(2.5)) outside and inside the homes as well as personal PM(2.5) during winter and spring sessions of 2000-2001. Nineteen subjects 6-13 years of age participated; 9 of the 19 were on inhaled corticosteroid (ICS) therapy. Exhaled breath measurements were collected offline into a Mylar balloon for up to 10 consecutive days. Mean eNO values were 19.1 (SD +/- 11.4) ppb in winter sessions and 12.5 +/- 6.6 ppb in spring sessions. Fixed-site PM(2.5) mean concentrations were 10.1 +/- 5.7 microg/m(3) outside homes and 13.3 +/- 1.4 inside homes; the personal PM(2.5) mean was 13.4 +/- 3.2 microg/m(3). We used a linear mixed-effects model with random intercept and an interaction term for medications to test for within-subject-within-session associations between eNO and various PM(2.5) values. We found a 10 microg/m(3) increase in PM(2.5) from the outdoor, indoor, personal, and central-site measurements that was associated with increases in eNO in all subjects at lag day zero. The effect was 4.3 ppb [95% confidence interval (CI), 1.4-7.29] with the outdoor monitor, 4.2 ppb (95% CI, 1.02-7.4) for the indoor monitor, 4.5 ppb (95% CI, 1.02-7.9) with the personal monitor, and 3.8 ppb (95% CI, 1.2-6.4) for the central monitors. The interaction term for medication category (ICS users vs. nonusers) was significant in all analyses. These findings suggest that eNO can be used as an assessment tool in epidemiologic studies of health effects of air pollution.

A midline dissociation between error-processing and response-conflict monitoring

Midline brain activation subsequent to errors has been proposed to reflect error detection and, alternatively, conflict-monitoring processes. Adjudicating between these alternatives is challenging as both predict high activation on error trials. In an effort to resolve these interpretations, subjects completed a GO/NOGO task in which errors of commission were frequent and response conflict was independently varied by manipulating response speeds. A mixed-block and event-related fMRI design identified task-related, tonic activation and event-related activations for correct and incorrect trials. The anterior cingulate was the only area with error-related activation that was not modulated by the conflict manipulation and hence is implicated in specific error-related processes. Conversely, activation in the pre-SMA was not specific to errors but was sensitive to the conflict manipulation. A significant region by conflict interaction for tonic activation supported a functional dissociation between these two midline areas. Finally, an intermediate, caudal cingulate area was implicated in both error processing and conflict monitoring. The results suggest that these two action-monitoring processes are distinct and dissociable and are localised along the midline.

Host and geographic range extensions of the North American strain of viral hemorrhagic septicemia virus

Viral hemorrhagic septicemia virus (VHSV) was isolated from populations of Pacific sardine Sardinops sagax from the coastal waters of Vancouver Island, British Columbia, Canada, and central and southern California, USA. The virus was also isolated from Pacific mackerel Scomber japonicus in southern California, from eulachon or smelt Thaleichthys pacificus, and surf smelt Hypomesus pretiosus pretiosus from Oregon, USA. Mortality and skin lesions typical of viral hemorrhagic septicemia in other marine fish species were observed among sardine in Canada and in a few surf smelt from Oregon, but the remaining isolates of VHSV were obtained from healthy appearing fish. The prevalence of VHSV among groups of apparently healthy sardine, mackerel and smelt ranged from 4 to 8%, in California and Oregon. A greater prevalence of infection (58%) occurred in groups of sardine sampled in Canada that sustained a naturally occurring epidemic during 1998-99. A captive group of surf smelt in Oregon exhibited an 81% prevalence of infection with clinical signs in only a few fish. The new isolates were confirmed as North American VHSV and were closely related based on comparisons of the partial nucleotide sequence of the glycoprotein (G) gene. The VHSV isolates from sardine in Canada and California were the most closely related, differing from isolates obtained from other marine fish species and salmonids in British Columbia, Canada, Alaska and Washington, USA. These new virus isolations extend both the known hosts (sardine, mackerel and 2 species of smelt) and geographic range (Oregon and California, USA) of VHSV.

Exposure to ambient fine particulate matter and primary cardiac arrest among persons with and without clinically recognized heart disease

The authors studied the association between incidence of primary cardiac arrest and daily measures of fine particulate matter (</=2.5 micro m) using a case-crossover study of 1,206 Washington State out-of-hospital cardiac arrests (1985-1994) among persons with (n = 774) and without (n = 432) clinically recognized heart disease. The authors compared particulate matter levels on the day of the cardiac event and the 2 days preceding the event with levels from matched reference days. The estimated relative risk for a 13.8- micro g/m(3) increase in fine particulate matter (nephelometry: 0.54 x 10(-1) km(-1 )bsp) on the day prior to cardiac arrest was 0.94 (95% confidence interval: 0.88, 1.02). Pollutant levels measured on the same day as the event and on the 2 days preceding the event demonstrated similar results. No increased risk was found among all cases with preexisting cardiac disease (odds ratio = 0.97, 95% confidence interval: 0.89, 1.07); however, an unexpected association appeared between current smokers with preexisting heart disease and increased particulate matter levels 2 days prior to the event (odds ratio = 1.29, 95% confidence interval: 1.06, 1.55). This association was not present in the 0- or 1-day lag analyses or in persons with other diseases. There was no consistent association between increased levels of fine particulate matter and risk of primary cardiac arrest.

Prevalence of cardiovascular risk factors in an African, urban inner city community

With the epidemiological transition phenomenon, more countries are expected to move from a disease pattern dominated by infectious diseases to one characterised by non-communicable diseases. Many developing countries are contending with infectious diseases as well as non-communicable diseases, yet little is known about the prevalence of cardiovascular risk factors in poor urban communities in developing countries. The objective of this community based study was to determine the prevalence of selected cardiovascular risk factors in an urban inner city community which had been followed up prospectively from 1993 to 1998. Results show that the prevalence of hypertension (Blood Pressure BP > 160/95 mm Hg) was 12.4 percent with an age-adjusted rate of 7.4 percent. This is higher than what is found in the rural parts of the country but much lower than what is generally observed in industrialized countries of the world. Though there was no significant difference in the proportion with hypertension by gender (P > 0.05), the mean systolic BP was significantly higher for men (123.9 +/- 23.9) mm Hg) than for women (120.6 +/- 26.8 mg Hg) t = 2.93, p < 0.01. The mean diastolic BP was similarly higher for men (75.8 +/- 14.9) mm Hg than women (74.0 +/- 14.9) mm Hg t = 2.76 p < 0.01). Eight percent of the study population were obese (BMI > 30), and generally, more women than men were obese. However, at ages 15-19 significantly more males than females were obese (X2 = 73, p < 0.01). Both mean systolic and diastolic BP increased with increasing weight. When adjusting for gender, the association between hypertension and other CVD risk factors remained similar for males and females and gender was not a modifier of the factors. Of the CVD risk factors studied, Age > 40 years and obesity, were significantly associated with the presence of hypertension in this community (P < 0.0001 and P < 0.0001), smoking, alcohol intake and gender were not (P > 0.05). It is necessary to implement a national plan for the control of cardiovascular diseases in order to reduce and keep to minimum cardiovascular diseases and its complications in the country.

Effects of early stress on brain structure and function: implications for understanding the relationship between child maltreatment and depression

Child abuse is associated with markedly elevated rates of major depression (MDD) in child, adolescentt, and adult cohorts. This article reviews preclinical (e.g., animal) studies of the effects of early stress and studies of the neurobiological correlates of MDD in adults and children, and it highlights differences in the neurobiological correlates of MDD and stress at various developmental stages. The preclinical studies demonstrate that stress early in life can alter the development multiple neurotransmitter systems and promote structural and functional alterations in brain regions similar to those seen in adults with depression. Preclinical and clinical studies suggest, however, that long-term neurobiological changes associated with early stress can be modified by familial/genetic factors, the quality of the subsequent caregiving environment, and pharmacological interventions. Little is known about how developmental factors interact with experiences of early stress and these other modifying factors. Moreover, in cases of child maltreatment, the effects of early abuse are often exacerbated by failures in the child protection system and repeat out-of-home placements. Given the number of factors that impact on the long-term outcome of maltreated children, multidisciplinary research efforts are recommended to address this problem-with foci that span from neurobiology to social policy.

School-associated violent deaths in the United States, 1994-1999

CONTEXT

Despite the public alarm following a series of high-profile school shootings that occurred in the United States during the late 1990s, little is known about the actual incidence and characteristics of school-associated violent deaths.

OBJECTIVE

To describe recent trends and features of school-associated violent deaths in the United States.

DESIGN, SETTING, AND SUBJECTS

Population-based surveillance study of data collected from media databases, state and local agencies, and police and school officials for July 1, 1994, through June 30, 1999. A case was defined as a homicide, suicide, legal intervention, or unintentional firearm-related death of a student or nonstudent in which the fatal injury occurred (1) on the campus of a public or private elementary or secondary school, (2) while the victim was on the way to or from such a school, or (3) while the victim was attending or traveling to or from an official school-sponsored event.

MAIN OUTCOME MEASURES

National estimates of risk of school-associated violent death; national trends in school-associated violent deaths; common features of these events; and potential risk factors for perpetration and victimization.

RESULTS

Between 1994 and 1999, 220 events resulting in 253 deaths were identified; 202 events involved 1 death and 18 involved multiple deaths (median, 2 deaths per multiple-victim event). Of the 220 events, 172 were homicides, 30 were suicides, 11 were homicide-suicides, 5 were legal intervention deaths, and 2 were unintentional firearm-related deaths. Students accounted for 172 (68.0%) of these deaths, resulting in an estimated average annual incidence of 0.068 per 100 000 students. Between 1992 and 1999, the rate of single-victim student homicides decreased significantly (P =.03); however, homicide rates for students killed in multiple-victim events increased (P =.047). Most events occurred around the start of the school day, the lunch period, or the end of the school day. For 120 (54.5%) of the incidents, respondents reported that a note, threat, or other action potentially indicating risk for violence occurred prior to the event. Homicide offenders were more likely than homicide victims to have expressed some form of suicidal behavior prior to the event (odds ratio [OR], 6.96; 95% confidence interval [CI], 1.96-24.65) and been bullied by their peers (OR, 2.57; 95% CI, 1.12-5.92).

CONCLUSIONS

Although school-associated violent deaths remain rare events, they have occurred often enough to allow for the detection of patterns and the identification of potential risk factors. This information may help schools respond to this problem.

Examination of predictors of severe violence in combat-exposed Vietnam veterans

This study examined several proposed predictors of severe wartime violence in a randomly selected, nationally representative sample of 1,125 Vietnam veterans. Participation in severe acts of violence during wartime was reported by 7.6% of the sample. Disruptive behavior before the age of 15 and increased combat exposure were both significant predictors of severe wartime violence. Childhood contextual factors were indirectly related to severe wartime violence via prewar disruptive behavior. The classification rate of perpetrators of severe violence was comparable to rates from studies of less severe forms of violence. The implications of these results and suggestions for future research in this area are discussed.

Comorbidity of mood and anxiety disorders

This article reviews data on the prevalence of panic, social phobia, generalized anxiety, and posttraumatic stress disorder, and research documenting the comorbidity of these disorders with major depression (MDD). These anxiety disorders are frequently comorbid with MDD, and 50-60% of individuals with MDD report a lifetime history of one or more of these anxiety disorders. The anxiety disorders are also highly correlated with one another, and approximately one-quarter to one-half of individuals with each of the anxiety disorders report a lifetime history of an alcohol or substance use disorder. Anxiety disorders rarely exist in isolation, with several studies reporting that over 90% of individuals with anxiety disorders have a lifetime history of other psychiatric problems. Implications for research are discussed, including the potential benefit of using combined categorical and dimensional rating scale approaches in future genetic, biochemical, neuroimaging, and treatment studies. The clinical implications of the findings are also discussed, and the results of recent clinical trials summarized. Available data suggests selective serotonin reuptake inhibitors are the first-line pharmacological treatment for these disorders, and that newer serotonin and norepinephrine reuptake inhibitors show significant promise, especially for comorbid cases. Comorbidity among depression and anxiety disorders is associated with greater symptom severity, and a considerably higher incidence of suicidality. Increased public awareness about these disorders and the availability of effective treatments is sorely needed.

Screen for Child Anxiety-Related Emotional Disorders (SCARED): convergent and divergent validity

The purpose of this study was to examine the Screen for Child Anxiety-Related Emotional Disorders' (SCARED) divergent and convergent validity and its ability to identify anxious children. The SCARED, the Child Behaviour Checklist (CBCL), and the State-Trait Anxiety Inventory for Children (STAIC) were administered to children, adolescents (n = 295), and their parents attending an outpatient mood and anxiety disorders clinic. DSM-IIIR/IV diagnoses were made using a semistructured interview (n = 130) or a symptom checklist (n = 165). The Multi-Trait Multi-Method Matrix was used to assess construct validity, and Receiver Operating Curve analysis was used to assess the sensitivity and specificity of the SCARED, CBCL, and STAIC. The SCARED correlated significantly better with the CBCL's internalizing factors than with the externalizing factors. In addition, parent and child forms of the SCARED correlated significantly with the trait and state subscales of the STAIC. Children with an anxiety disorder scored significantly higher on the SCARED than children with depression only or disruptive disorders only (P < 0.05), thus demonstrating the discriminant validity of the SCARED. The SCARED is a reliable and valid screening tool for clinically referred children and adolescents with anxiety disorders.

Are child-, adolescent-, and adult-onset depression one and the same disorder?

This paper reviews prior research studies examining neurobiological correlates and treatment response of depression in children, adolescents, and adults. Although there are some similarities in research findings observed across the life cycle, both children and adolescents have been found to differ from depressed adults on measures of basal cortisol secretion, corticotropin stimulation post-corticotropin releasing hormone (CRH) infusion, response to several serotonergic probes, immunity indices, and efficacy of tricyclic medications. These differences are proposed to be due to 1) developmental factors, 2) stage of illness factors (e.g., number of episodes, total duration of illness), or 3) heterogeneity in clinical outcome (e.g., recurrent unipolar course vs. new-onset bipolar disorder). Relevant clinical and preclinical studies that provide support for these alternate explanations of the discrepant findings are reviewed, and directions for future research are discussed. To determine whether child-, adolescent-, and adult-onset depression represent the same condition, it is recommended that researchers 1) use the same neuroimaging paradigms in child, adolescent, and adult depressed cohorts; 2) carefully characterize subjects' stage of illness; and 3) conduct longitudinal clinical and repeat neurobiological assessments of patients of different ages at various stages of illness. In addition, careful attention to familial subtypes (e.g., depressive spectrum disorders vs. familial pure depressive disorders) and environmental factors (e.g., trauma history) are suggested for future investigations.

The CD40-CD40 ligand system: a potential therapeutic target in atherosclerosis

Atherosclerosis is a leading cause of cardiovascular disease in the westernized world. This review highlights emerging evidence linking atherosclerosis to the CD40-CD40 ligand (CD154) pathway. Recently, atherosclerosis has been associated with chronic inflammation, linking it to the immune system. This novel viewpoint may serve as an additional target for therapeutic intervention. CD40 and CD154 are highly expressed in atherosclerotic human plaques. Recent data from preclinical animal models of atherosclerosis show that disruption of the CD40-CD154 pathway can prevent atherosclerotic progression and may reverse established lesions. Blockade of the CD40-CD154 pathway by biologicals or small molecules may prove valuable in the treatment of atherosclerosis.

Comparison of self-report, video observation and direct measurement methods for upper extremity musculoskeletal disorder physical risk factors

The prevention of work-related musculoskeletal disorders has become a national priority in many countries. Increasingly, attempts are made to quantify those exposures that increase risk in order to set exposure limit values. This study used commonly employed field measurement methods and tools in order to perform an inter-method comparison between three primary methods of risk factor exposure assessment: self-report questionnaires, observational video analysis and direct measurement. Extreme posture duration, repetition, hand force (estimated from electromyography) and movement velocity were assessed for 18 subjects while performing each of three jobs processing tree seedlings. Results indicated that self-reports were the least precise assessment method, which consistently overestimated exposures for each of the measured risk factors. However, adjustment of the reports as psychophysical scales may increase agreement on a group level. Wrist flexion/extension duration and repetition were best measured by electrogoniometer. Electrogoniometric measures of wrist deviation duration and frequency were less precise than video analysis. Forearm rotation duration and repetition, grip force and velocity appeared to be best quantified by direct measurement as measured by electrogoniometer and electromyography (EMG) (as root-mean-square amplitude). The results highlight the fact that it is as important to consider and report estimated measurement error in order to reduce potential exposure misclassification in epidemiologic studies.

Referent selection in case-crossover analyses of acute health effects of air pollution

The case-crossover design was proposed for the study of a transient effect of an intermittent exposure on the subsequent occurrence of a rare acute-onset disease. This design can be an alternative to Poisson time series regression for studying the health effects of fine particulate matter air pollution. Characteristics of time-series of particulate matter, including long-term time trends, seasonal trends, and short-term autocorrelations, require that referent selection in the case-crossover design be considered carefully and adapted to minimize bias. We performed simulations to evaluate the bias associated with various referent selection strategies for a proposed case-crossover study of associations between particulate matter and primary cardiac arrest. Some a priori reasonable strategies were associated with a relative bias as large as 10%, but for most strategies the relative bias was less than 2% with confidence interval coverage within 1% of the nominal level. We show that referent selection for case-crossover designs raises the same issues as selection of smoothing method for time series analyses. In addition, conditional logistic regression analysis is not strictly valid for some case-crossover designs, introducing further bias.