Everyday home radon exposure is associated with altered structural brain morphology in youths

The refinement of brain morphology extends across childhood, and exposure to environmental toxins during this period may alter typical trends. Radon is a highly common radiologic toxin with a well-established role in cancer among adults. However, effects on developmental populations are understudied in comparison. This study investigated whether home radon exposure is associated with altered brain morphology in youths. Fifty-four participants (6-14yrs, M=10.52yrs, 48.15% male, 89% White) completed a T1-weighted MRI and home measures of radon. We observed a significant multivariate effect of home radon concentrations, which was driven by effects on GMV. Specifically, higher home radon was associated with smaller GMV (F=6.800, p=.012, ηp2=.13). Conversely, there was a trending radon-by-age interaction on WMV, which reached significance when accounting for the chronicity of radon exposure (F=4.12, p=.049, ηp2=.09). We found that youths with above-average radon exposure showed no change in WMV with age, whereas low radon was linked with normative, age-related WMV increases. These results suggest that everyday home radon exposure may alter sensitive structural brain development, impacting developmental trajectories in both gray and white matter.

Neurotoxic effects of home radon exposure on oscillatory dynamics serving attentional orienting in children and adolescents

Radon is a naturally occurring gas that contributes significantly to radiation in the environment and is the second leading cause of lung cancer globally. Previous studies have shown that other environmental toxins have deleterious effects on brain development, though radon has not been studied as thoroughly in this context. This study examined the impact of home radon exposure on the neural oscillatory activity serving attention reorientation in youths. Fifty-six participants (ages 6-14 years) completed a classic Posner cuing task during magnetoencephalography (MEG), and home radon levels were measured for each participant. Time-frequency spectrograms indicated stronger theta (3-7 Hz, 300-800 ms), alpha (9-13 Hz, 400-900 ms), and beta responses (14-24 Hz, 400-900 ms) during the task relative to baseline. Source reconstruction of each significant oscillatory response was performed, and validity maps were computed by subtracting the task conditions (invalidly cued - validly cued). These validity maps were examined for associations with radon exposure, age, and their interaction in a linear regression design. Children with greater radon exposure showed aberrant oscillatory activity across distributed regions critical for attentional processing and attention reorientation (e.g., dorsolateral prefrontal cortex, and anterior cingulate cortex). Generally, youths with greater radon exposure exhibited a reverse neural validity effect in almost all regions and showed greater overall power relative to peers with lesser radon exposure. We also detected an interactive effect between radon exposure and age where youths with greater radon exposure exhibited divergent developmental trajectories in neural substrates implicated in attentional processing (e.g., bilateral prefrontal cortices, superior temporal gyri, and inferior parietal lobules). These data suggest aberrant, but potentially compensatory neural processing as a function of increasing home radon exposure in areas critical for attention and higher order cognition.

Theta oscillatory dynamics serving cognitive control index psychosocial distress in youth

Background

Psychosocial distress among youth is a major public health issue characterized by disruptions in cognitive control processing. Using the National Institute of Mental Health's Research Domain Criteria (RDoC) framework, we quantified multidimensional neural oscillatory markers of psychosocial distress serving cognitive control in youth.

Methods

The sample consisted of 39 peri-adolescent participants who completed the NIH Toolbox Emotion Battery (NIHTB-EB) and the Eriksen flanker task during magnetoencephalography (MEG). A psychosocial distress index was computed with exploratory factor analysis using assessments from the NIHTB-EB. MEG data were analyzed in the time-frequency domain and peak voxels from oscillatory maps depicting the neural cognitive interference effect were extracted for voxel time series analyses to identify spontaneous and oscillatory aberrations in dynamics serving cognitive control as a function of psychosocial distress. Further, we quantified the relationship between psychosocial distress and dynamic functional connectivity between regions supporting cognitive control.

Results

The continuous psychosocial distress index was strongly associated with validated measures of pediatric psychopathology. Theta-band neural cognitive interference was identified in the left dorsolateral prefrontal cortex (dlPFC) and middle cingulate cortex (MCC). Time series analyses of these regions indicated that greater psychosocial distress was associated with elevated spontaneous activity in both the dlPFC and MCC and blunted theta oscillations in the MCC. Finally, we found that stronger phase coherence between the dlPFC and MCC was associated with greater psychosocial distress.

Conclusions

Greater psychosocial distress was marked by alterations in spontaneous and oscillatory theta activity serving cognitive control, along with hyperconnectivity between the dlPFC and MCC.

Effects of chronic home radon exposure on cognitive, behavioral, and mental health in developing children and adolescents

Introduction

It is well-established that chronic exposure to environmental toxins can have adverse effects on neuropsychological health, particularly in developing youths. However, home radon, a ubiquitous radiotoxin, has been seldom studied in this context. In the present study, we investigated the degree to which chronic everyday home radon exposure was associated with alterations in transdiagnostic mental health outcomes.

Methods

A total of 59 children and adolescents ages 6- to 14-years-old (M = 10.47 years, SD = 2.58; 28 males) completed the study. Parents completed questionnaires detailing aspects of attention and executive function. We used a principal components analysis to derive three domains of neuropsychological functioning: 1) task-based executive function skills, 2) self-and emotion-regulation abilities, and 3) inhibitory control. Additionally, parents completed a home radon test kit and provided information on how long their child had lived in the tested home. We computed a radon exposure index per person based on the duration of time that the child had lived in the home and their measured home radon concentration. Youths were divided into terciles based on their radon exposure index score. Using a MANCOVA design, we determined whether there were differences in neuropsychological domain scores across the three groups, controlling for age, sex, and socioeconomic status.

Results

There was a significant multivariate effect of radon group on neuropsychological dysfunction (λ = 0.77, F = 2.32, p = 0.038, ηp2 = 0.12). Examination of univariate effects revealed specific increases in self-and emotion-regulation dysfunction among the youths with the greatest degree of chronic home radon exposure (F = 7.21, p = 0.002, ηp2 = 0.21). There were no significant differences by group in the other tested domains.

Discussion

The data suggest potential specificity in the neurotoxic effects of everyday home radon exposure in developing youths, with significant aberrations in self-and emotion-regulation faculties. These findings support the need for better public awareness and public health policy surrounding home radon safety and mitigation strategies.

Developmental alterations in the neural oscillatory dynamics underlying attentional reorienting

The neural and cognitive processes underlying the flexible allocation of attention undergo a protracted developmental course with changes occurring throughout adolescence. Despite documented age-related improvements in attentional reorienting throughout childhood and adolescence, the neural correlates underlying such changes in reorienting remain unclear. Herein, we used magnetoencephalography (MEG) to examine neural dynamics during a Posner attention-reorienting task in 80 healthy youth (6-14 years old). The MEG data were examined in the time-frequency domain and significant oscillatory responses were imaged in anatomical space. During the reorienting of attention, youth recruited a distributed network of regions in the fronto-parietal network, along with higher-order visual regions within the theta (3-7 Hz) and alpha-beta (10-24 Hz) spectral windows. Beyond the expected developmental improvements in behavioral performance, we found stronger theta oscillatory activity as a function of age across a network of prefrontal brain regions irrespective of condition, as well as more limited age- and validity-related effects for alpha-beta responses. Distinct brain-behavior associations between theta oscillations and attention-related symptomology were also uncovered across a network of brain regions. Taken together, these data are the first to demonstrate developmental effects in the spectrally-specific neural oscillations serving the flexible allocation of attention.

Psychological research on the martial arts: an addendum to Fuller's review

Most psychological research on the martial arts has been conducted from a positivist stance, and Fuller's (1988) review of research reflected a positivist tone while suggesting that therapeutic influences may be achieved from martial arts training methods abstracted from their traditional setting. This addendum cites two important contextual problems influencing martial arts research. First, the martial arts are influenced by Oriental styles of thinking such as Taoism and Zen Buddhism that are difficult to grasp from a Western positivist point of view. We suggest that phenomenology seems to have some stylistic parallels with Oriental thinking and appears to offer the Westerner a point of entry toward understanding the martial arts as Oriental arts. Second, the cultural and psychological values and meanings of the Oriental martial arts may change when situated in a Western context, thus changing their method, content, and therapeutic influence. We suggest that a non-positivist and context-sensitive approach such as phenomenology might clarify the contextual intricacy of the martial arts and thereby facilitate improved theoretical foundations and empirical research of martial arts participation as a psychological phenomenon.

Flow-dependence of extravascular thermal volume as an index of pulmonary edema

Using a double indicator (dye and heat) dilution technique of extravascular lung water measurement, we examined the effect of a reduction in cardiac output and positive pressures on the extravascular thermal volume (EVTV) in dogs. Following baseline EVTV measurements, cardiac output was lowered by inflation of balloons in the superior and inferior vena cavas, as well as by bleeding, and positive pressures were applied to the airways. There was good agreement between the baseline EVTV and post-mortem lung water; however, as the cardiac output was lowered there was a reduction in the measured EVTV. In other animals following application of positive airway pressure there was a decrease in the EVTV which appeared to be related to the reduction in cardiac output caused by positive airway pressure. At least in part, loss of thermal indicator appeared to explain the reduction in EVTV. Measurement of EVTV as an index of pulmonary edema may not be accurate in the face of a changing cardiac output.

Closing volumes with variations in pulmonary capillary wedge pressure

Increased closing volumes have been documented in patients in whom there was suspected to be early pulmonary edema due to increased pulmonary capillary wedge pressure. However, the relationship between the actual pulmonary capillary wedge pressure and closing volume has not been established. To attempt to define this relationship and to determine whether the closing volume might be a useful indicator of the onset of pulmonary edema, we measured the closing volume in dogs while sequentially increasing the pulmonary capillary wedge pressure by way of a left atrial balloon. We found a small but significant increase in closing volume (p less than 0.01) when a pulmonary capillary wedge pressure of 25 mm Hg was achieved, and it was at this pressure that pulmonary edema would hypothetically be expected to begin.

Effect of methylprednisolone on experimental noncardiogenic pulmonary edema

Methylprednisolone, 30 mg/kg body weight, was given to dogs 30 min and 4 h after injection of monocrotaline to produce noncardiogenic pulmonary edema. Control animals received monocrotaline but not corticosteroids. After 6 h the steroid-treated animals demonstrated significantly butter gas exchange and significantly less pulmonary edema. A possible mechanism of this beneficial effect of steroids is inhibition of complement-leukocyte interactions which may mediate pulmonary microvascular injury. The results lend some support to the clinical practice of short-term pharmacologic doses of steroids in noncardiogenic pulmonary edema.

Effect of PEEP on lung water content in experimental noncardiogenic pulmonary edema

After administration of monocrotaline to dogs to produce noncardiogenic pulmonary edema, one-half of the animals (controls) were treated with intermittent positive pressure breathing (IPPV), and one-half with that ventilation plus the addition of 10 cm H2O of positive end-expiratory pressure (PEEP). After 6 h, the animals treated with PEEP demonstrated significantly better arterial oxygenation and reduced AaDO2, but lung water, quantitated either postmortem or in vivo by indicator-dilution techniques, was no less than controls. Although PEEP improves gas exchange, it fails to modify the degree of pulmonary edema represent.

A comparison of oral terbutaline and fenoterol in asthma

The effects of fenoterol and terbutaline, new beta 2 selective bronchodilators each administered orally in five mgm doses, was assessed in 33 asthmatics treated for six weeks. Both agents appeared to be equally potent bronchodilators with equally prolonged duration of action. Adrenergic side effects were half as frequent with fenoterol as compared to terbutaline. With both agents statistically significant drug tolerance developed--the clinical significance of which is unknown.

Respiratory failure in cancer patients

A review of 180 cancer patients requiring mechanical ventilation disclosed that 26% survived to extubation, and 13% and 7% were alive at two and six months, respectively. Mortality was related to several factors individually and the cumulative number of organ systems dysfunctioning in a given patient. Compared with general intensive care patients, those with respiratory failure and neoplastic disease demonstrated a high incidence of drug-induced pulmonary disease, hematologic abnormalities, pneumothorax, and infections with multiple and unusual organisms--all of which alter the approach to management. Although the long-term survival was poor, immediate survival was comparable with that of many groups of patients with respiratory failure.

Inhaled atropine in asthma

Ten adult asthmatics inhaled atropine and isoproterenol to determine the site of action in the airways and relative effectiveness of the two drugs. The two agents were equal in their effect on lung volumes and airway resistance but isoproterenol produced significantly better flows. Atropine was shown to be an effective bronchodilator with a predominant site of action in large airways. The authors believe atropine and atropine derivatives deserve ongoing investigation, especially regarding potential side effects of retarding mucociliary clearance and the clinical significance of apparent failure to dilate small airways.

Monocrotaline model of noncardiogenic pulmonary edema in dogs

Monocrotaline, a plant alkaloid shown histologically to produce pulmonary endothelial damage and edema, was used in dogs to produce an acute model of noncardiogenic pulmonary edema. Following intravenous injection there was no change in pulmonary vascular pressures or heart rate; cardiac output fell and pulmonary vascular resistance increased. After 2 h measurement of lung water demonstrated modest pulmonary edema in all animals. The degree of edema produced was more consistent and reproducible than that following alloxan or alpha-naphthylthiourea.

Contribution of systemic venous hypertension to the development of pulmonary edema in dogs

Systemic venous hypertension (SVH) is a frequent finding in pulmonary edema. To study the possible contributory or even causal role of SVH in pulmonary edema, a dog model was developed in which balloon catheters were placed in the left and right atria. Inflation of the left atrial balloon produced a tendency to pulmonary edema by causing pulmonary venous hypertension (PVH) (pulmonary artery wedge pressure of 20 mmHg). Inflation of the right atrial balloon produced SVH (central venous pressure of 15 mm Hg). After 2 hours, dogs with SVH with or without PVH demonstrated a greater amount of lung fluid accumulation (P less than 0.01) compared to controls or PVH alone. There was no significant difference in lung water in SVH dogs with or without PVH. Pulmonary blood flow was not significantly different between the experimental groups, each of which was less than control. Impairment of pulmonary lymphatic flow is one possible mechanism producing the worsening edema; however, bronchial venous hypertension or neurogenic reflexes cannot be excluded. We conclude that the contribution of systemic venous hypertension to the development of pulmonary edema may have therapeutic implications.

Minocycline treatment failure in pneumonia caused by minocycline-sensitive Streptococcus pneumoniae

A previously healthy 23-year-old white woman had fulminant pneumococcal pneumonia complicated by empyema and bilateral pneumothoraces. Despite early treatment with the recommended doses of minocycline, the disease progressed. The S pneumoniae isolate was resistant to a 30microgram tetracycline disk and showed an MIC of 3.13microgram/ml for minocycline and 12.5 microgram/ml for tetracycline; these levels are considered by the manufacturer to indicate sensitivity to minocycline and intermediate sensitivity to tetracycline. The tetracyclines, including minocycline, should not be used to treat bacterial pneumonia since resistant strains of pneumococci are not uncommon and inffective treatment can lead to rapid progression of the infection. This case suggests that the levels of minocycline considered to indicate sensitivity in vitro be reassessed.

Chemical pneumonitis secondary to inhalation of epoxy pipe coating

Two patients with chemical pneumonitis secondary to inhalation of an epoxy curing material used in the coating of pipes had similar patterns of cough, hemoptysis, and dyspnea associated with diffuse bilateral alveolar infiltrates shortly following the exposure. Pulmonary function studies showed a volume-restrictive defect with severe hypoxemia, but an elevated diffusing capacity. All lung function studies returned toward normal within 1 month of exposure. One patient underwent an open lung biopsy which showed changes consistent with a nonspecific injury to the alveolar wall. This epoxy curing material, trimellitic anhydride, represents another cause of diffuse lung injury that can result in pulmonary edema.

Left ventricular function during respiratory failure

Indirect measures of left ventricular function were studied in seven patients with respiratory failure secondary to chronic obstructive pulmonary disease to determine if there were a relationship between left ventricular function and treatment of the pulmonary disease. All patients were studied during acute episodes while in respiratory failure having arterial Pco2 (Paco2) values greater than 49 torr with no clinical evidence of left ventricular failure. Indirect methods to evaluate left ventricular function included the use of the Swan-Ganz catheter for pulmonary capillary wedge pressure measurement, systolic time intervals, and cardiac output. There was improvement in left ventricular function with treatment of the respiratory failure manifested by decreases in the wedge pressure and pre-ejection period/left ventricular ejection time ratio, and an increase in the dp/dt/pulmonary capillary wedge pressure with treatment of the chronic obstructive pulmonary disease. The improvement in left ventricular function suggests that there is a depression of left ventricular function in respiratory failure. The depressed function improved with therapy of the lung disease without additional medication directed at cardiac function.