Interhemispheric transfer time and concussion in adolescents: A longitudinal study using response time and event-related potential measures

Introduction

Concussion in children and adolescents is a public health concern with higher concussion incidence than adults and increased susceptibility to axonal injury. The corpus callosum is a vulnerable location of concussion-related white matter damage that can be associated with short- and long-term effects of concussion. Interhemispheric transfer time (IHTT) of visual information across the corpus callosum can be used as a direct measure of corpus callosum functioning that may be impacted by adolescent concussion with slower IHTT relative to matched controls. Longitudinal studies and studies testing physiological measures of IHTT following concussion in adolescents are lacking.

Methods

We used the N1 and P1 components of the scalp-recorded brain event-related potential (ERP) to measure IHTT in 20 adolescents (ages 12–19 years old) with confirmed concussion and 16 neurologically-healthy control participants within 3 weeks of concussion (subacute stage) and approximately 10 months after injury (longitudinal).

Results

Separate two-group (concussion, control) by two-time (3 weeks, 10 months) repeated measures ANOVAs on difference response times and IHTT latencies of the P1 and N1 components showed no significant differences by group (ps ≥ 0.25) nor by time (ps ≥ 0.64), with no significant interactions (ps ≥ 0.15).

Discussion

Results from the current sample suggest that measures of IHTT may not be strongly influenced at 3 weeks or longitudinally following adolescent concussion using the current IHTT paradigm.

The relationship between acute stress and neurophysiological and behavioral measures of food-related inhibitory control: An event-related potential (ERP) study

Stress influences many health-related behaviors including diet and nutrition intake, often resulting in increased calorie intake, fewer healthy eating behaviors, and poorer nutrition. Food intake is modulated by inhibitory control and has important implications for our physical, mental, and emotional health. Yet, little is known about the relationship between stress and food-related inhibitory control. We tested the influence of a short-term experimental stressor on behavioral and event-related potential (ERP; N2 and P3 components) measures of food-related inhibitory control. Ninety-seven healthy participants were randomly assigned to complete the Trier Social Stress Test (TSST) (n = 48, 27 females [52.9%]) or a neutral control condition (n = 49, 35 females [70%]) immediately followed by food-specific go/no-go and neutral go/no-go tasks while electroencephalogram (EEG) data were recorded. Stress levels were successfully manipulated, with heightened self-report and physiological measures (heart rate and systolic blood pressure) of the stress response in individuals who completed the TSST compared to control. As expected, the high calorie food-specific go/no-go task elicited larger N2 amplitude than the neutral task. N2 component amplitude was also significantly larger following the TSST relative to the control task. There were no significant between-group or task differences for P3 amplitude or behavioral measures. Findings suggest heightened N2 amplitude following psychological stress that is not specific to food or inhibition processes and may reflect heightened arousal following stress. Future research in individuals with overweight/obesity or experiencing chronic stress will further clarify the role of stress in food-related inhibitory control.

Neural mechanisms that promote food consumption following sleep loss and social stress: An fMRI study in adolescent girls with overweight/obesity

STUDY OBJECTIVES

Insufficient sleep and social stress are associated with weight gain and obesity development in adolescent girls. Functional magnetic resonance imaging (fMRI) research suggests that altered engagement of emotion-related neural networks may explain overeating when under stress. The purpose of this study is to explore the effects of acute sleep restriction on female adolescents' neural responding during social evaluative stress and their subsequent eating behavior.

METHODS

Forty-two adolescent females (ages 15-18 years) with overweight or obesity completed a social stress induction task in which they were told they would be rated by peers based on their photograph and profile. Participants were randomly assigned to one night of sleep deprivation or 9 hours of sleep the night before undergoing fMRI while receiving positive and negative evaluations from their peers. After which, subjects participated in an ad libitum buffet.

RESULTS

Sleep deprived, relative to non-deprived girls had distinct patterns of neural engagement to positive and negative evaluation in anterior, mid, and posterior aspects of midline brain structures. Moreover, a sleep deprivation-by-evaluation valence-by-caloric intake interaction emerged in bilateral dorsal anterior cingulate. Among sleep deprived girls, greater engagement during negative, but not positive, feedback was associated with lower caloric intake. This was not observed for non-sleep deprived girls.

CONCLUSIONS

Results suggest an interaction between acute sleep loss and social evaluation that predicts emotion-related neural activation and caloric intake in adolescents. This research helps to elucidate the relationship between sleep loss, social stress, and weight status using a novel health neuroscience model.

Five types of African-American marriages

This study developed a marital typology based on a nonrandom, national sample of 415 African-American couples who took the Enriching Relationship Issues, Communication and Happiness (ENRICH) marital assessment inventory. Five types of African-American marriages were identified through cluster analysis using the positive couple agreement (PCA) scores in 10 relationship domains. Relationships between marital satisfaction, marital stability, and the five marital types were then analyzed. The five types (from highest marital satisfaction to lowest) were labeled as vitalized, harmonious, traditional, conflicted, and devitalized. The results were similar to findings in studies of ethnically mixed (predominantly European-American) marital samples including the number and characteristics of marital types.

The treatment of rigid metatarsus adductovarus with the use of a new hinged adjustable shoe orthosis

A retrospective review of the early results of treatment of metatarsus adductovarus with a new hinged adjustable shoe orthosis, the Bebax shoe, is presented. The results in 120 cases (210 feet) are included in the study. Criteria for severity of the initial deformity were developed, and all cases of true clubfoot and those cases with prior treatment were excluded. The average age at institution of treatment was 4.5 months, and treatment time averaged 2.7 months (range 1-7 months). Overall, 96% of the cases were completely resolved with the use of the orthotic alone, 3% required additional casting, and 1% required a bar and shoes for complete correction of the deformity. No treatment complications were encountered except some minor problems with hinge loosening, particularly in the child of walking age. We believe that the Bebax shoe is a lightweight, convenient, safe, and both cost- and treatment-effective device in the management of metatarsus adductovarus.

The relative frequencies and distribution of immunoglobulin-bearing cells in the intestinal mucosa of neonatal and weaned pigs and their significance in the development of secretory immunity

A comparative immunohistochemical study has been made of cells containing immunoglobulins IgM; IgA and IgG in the intestines of pigs varying in age from 2 days to 12 weeks. Cells with cytoplasmic IgM appeared in the lamina propria earlier than those containing either IgA or IgG. The duodenum appeared to be the preferred site of infiltration, the numbers of cells occurring in duodenal mucosa were consistently higher than at other levels of intestine irrespective of immunoglobulin class. Igm cells formed the majority of immunoglobulin contained cells in the lamina propria of the small bowel in suckling pigs upto 4 weeks of age. But in the weaned animal the proportion of IgM cells gradually declined with maturity until by the time the pigs were 12 weeks old nearly 90 per cent of the cells contained IgA.

Intestinal immune response to E. coli antigens in the germ-free chicken

The secretory intestinal immune response to live and heat-inactivated E. coli 02 has been studied in young germ-free chicks. A response to live organisms was evident from an infiltration of the intestinal mucosa with IgA and IgM immunoglobulin-producing cells (IPC). Antibody associated with both immunoglobulin classes which was specific for E. coli 02 was demonstrated in saline extracts of contents from the small intestine. Repeated oral immunization with heat-killed E. coli 02 failed to stimulate serum or intestinal antibody. This finding reflected the complete absence of IPC within the intestinal mucosa of these birds. The IPC profile of unimmunized germ-free chicks was identical to that seen in chicks orally immunized with inactivated E. coli. An interesting feature of all gnotobiotic birds was a considerable elevation of serum IgM levels, compared to those of conventional birds, which was unassociated with immunization procedures. Serum IgG and IgA levels in gnotobiotes were much lower than those in the serum of conventional birds of comparable age. Studies on the fate of orally administered antigen using radiolabelled E. coli endotoxin indicated that a proportion remained intact as far down the intestinal tract as the caecum. However, unaccountably high levels of low mol. wt antigen in the faeces suggested degradation, intestinal absorption and subsequent excretion of endotoxin fragments in the urine. The differences between the avian response and that observed in mammals are discussed in relation to the comparative roles of Peyer's patches and the bursa of Fabricius in initiating intestinal immununity.

Significance of immune mechanisms in relation to enteric infections of the gastrointestinal tract in animals

The impact of bacterial colonization on the alimentary tract in early life is reflected in gross changes in morphology. Subsequent health, if not survival, may largely be determined by a continuum of local intestinal immune mechanisms and it is essential for antibody development during the neonatal period to compensate adequately for declining passive maternal antibody. Consequent upon the development of the gut microflora the lamina becomes infiltrated with immunocytes in which the dominant immunoglobulins produced are IgM and IgA. Both immunoglobulins are transported across the epithelium by a process involving membrane-bound vesicles. Germ-free and fistulated pigs and calves are shown to be able to respond to oral immunization with Escherichia coli O somatic antigens during the first week of life. Resistance to infection with enteropathogenic E. coli was significantly enhanced, along with other parameters of nutrition and performance. However, in the young chick, although the intestinal response to infection with E. coli was similar to that in the mammal, no response to E. coli O antigens could be determined on oral administration in germ-free or local intestinal applications in fistulated birds. In the mammalian intestine secretory antibodies participate in the control of pathogenic E. coli by blocking adhesion to the mucosal epithelium, interfering with the elaboration of surface antigens, inhibiting toxins, and facilitating rapid elimination from the alimentary tract by agglutination and bacteriostasis. In consequence fewer enteropathogens are excreted into the environment, an important feature in modern intensive systems of animal production.

Evidence for the secretory transport mechanism of intestinal immunoglobulin. The ultrastructural distribution of IgM

The intracellular localization of IgM in porcine intestinal tissue has been studied by immunoelectron microscopy and immunofluorescence. IgM was demonstrated in vesicles in the cytoplasm of crypt epithelial cells particularly in the supranuclear region. It was also shown in the ergastoplasmic cisternae of plasma cells in the intercryptal lamina propria. The findings are compared with those of a previous similar study on secretory IgA and their implications for possible mechanisms of selective transport are discussed.

Localization of immunoglobulins in intestinal mucosa and the production of secretory antibodies in response to intraluminal administration of bacterial antigens in the preruminant calf

Immunofluorescent studies of intestinal tissues from young preruminant calves demonstrate the presence of two main populations of immunocytes synthesizing IgA and IgM. These cells had infiltrated the lamina propria of the intestine as early as 4 days of age. There was little evidence of any significant involvement of IgG1 in intestinal immune synthesis of calves at this age although activity was demonstrable in the ileum and colon of one calf. In general there were more IgG2-synthesizing cells than IgG1, but these were few compared with the main populations of IgA and IgM cells. Local antigenic stimulus to the intestinal mucosa of young fistulated calves using extracts of heat-killed Gram-negative bacteria produced antibody in the secretions over a period of approximately 3 weeks. A second administration of a similar antigenic dose produced a similar response indicating the requirement for continuous stimuli to maintain a measurable level of antibody secretion. Gel filtration and antiglobulin assays indicated that the antibacterial activity was predominantly associated with IgA and that IgM also played a significant role. Oral administration of bacterial antigens to colostrum-fed calves from 5 to 8 days of age produced a faecal antibody response, indicating that intestinal secretion could be successfully interrelated with the declining passive antibody to maintain an almost continuous level of intestinal antibody in early life.

Intestinal antibody secretion in the young pig in response to oral immunization with Escherichia coli

Intestinal immunoglobulins and antibodies in the local immune response to E. coli O somatic antigens have been studied in young fistulated pigs. Antibody levels in intestinal secretion were raised for approximately 2–3 weeks following a single local antigenic challenge with a heat-killed aqueous suspension of E. coli. A second challenge provoked a similar response suggesting a lack of immunological memory.

Antibody activity in the secretions was predominantly associated with IgA and immunofluorescent studies of biopsy specimens from young fistulated animals indicated that intestinal synthesis and secretion of IgA had commenced by the 10th day of life. Studies of piglets reared with the sow indicated that oral immunization with E. coli antigen after 10 days of age stimulated intestinal antibody secretion before weaning at 3 weeks.

The response of gnotobiotic pigs to oral immunization and infection was evaluated by immunofluorescent histology of the intestinal mucosa. Repeated oral administration of heat-killed E. coli O8 resulted in an immunocyte response in the lamina propria numerically comparable with that produced by infection with the live organism. The early response was dominated by cells of the IgM class whereas after 3 weeks IgA cells predominated. In the germ-free animal very few immunoglobulin-containing cells were detected.

In vitro studies of antibacterial activity indicated that the most probable mechanism of immunological control in the alimentary tract is bacteriostasis.

Localization of intracellular immunoglobulin A in porcine intestinal mucosa using enzyme-labelled antibody. An ultrastructural study

The intracellular localization of IgA in porcine intestinal tissue has been studied by immuno-electron microscopy and immunofluorescence.

IgA was demonstrated in vesicles occurring in the cytoplasm of crypt epithelial cells and in the intercellular spaces. It was also shown in the ergastoplasmic cisternae of plasma cells in the intercryptal lamina propria.

A model of the selective transport mechanism for IgA, based on these observations is proposed which is consistent with the findings of relatively large amounts of IgA in exocrine secretions and very little in the circulation.

The relative distribution of IgM and IgA cells in intestinal mucosa and lymphoid tissues of the young unweaned pig and their significance in ontogenesis of secretory immunity

A comparative study of cells synthesizing immunoglobulins IgA and IgM in intestinal mucosa and various lymphoid tissues of unweaned piglets has been made by immunofluorescence.

The lamina propria of the small intestine contained as many cells synthesizing IgM as those producing IgA. In all other lymphoid organs examined, including Peyer's patches, the number of IgM cells was significantly higher.

The largest population of intestinal immunocytes occurred in the lamina propria of the duodenum where the counts were ten times greater than in the jejunum or ileum.

The relevance of these findings to the earliest stages of development of secretory immunity in the young pig are considered.

Localization by immunofluorescence of secretory component and IgA in the intestinal mucosa of the young pig

The cellular distribution of IgA and secretory component in porcine intestinal mucosa has been studied by immunofluorescence. Secretory component was localized in crypt epithelium of all animals examined. It was also demonstrated in goblet cells on the villi of colostrum-fed neonates and of older animals, both colostrum-deprived and conventionally suckled, and in the crypt epithelial cells of an 80-day-old foetus and of colostrum-deprived new born animals. Sequential biopsy studies on a young fistulated animal demonstrated that the onset of active secretion of intestinal IgA did not occur before the second week of life. The significance of these findings is discussed in relation to the synthesis and transport of IgA.

Intestinal secretion of immunoglobulins in the preruminant calf

Intestinal immunoglobulins have been examined in secretions obtained from Thiry-Vella loops prepared in the mid-jejunum of six calves. Free secretory component and 11S IgA were demonstrated. Immunofluorescent studies of intestinal tissue confirmed the presence of a secretory IgA system similar to that described in other species. However quantitative assays showed that IgA was not at any time the predominant immunoglobulin in intestinal secretions. IgM consistently exceeded the level of IgA by approximately two-fold and its localization in lymphoid cells of the lamina propria and crypt epithelial cells suggested that IgM may normally play an important role in local intestinal defence in the calf.

IgG1 appeared in consistently low levels in intestinal secretions in spite of being the major serum immunoglobulin.

The demonstration of immunoglobulins in porcine intestinal tissue by immunofluorescence with observations on the effect of fixation

The localization of immunoglobulins IgA, IgG and IgM in porcine intestinal tissue by immunofluorescence is described and the influence of three fixatives, ethanol, methanol and acetone on the findings compared. Methanol was found to be the only fixative to give consistent results for IgM; it was also the reagent of choice for the localization of IgA in cells of the lamina propria. However ethanol and acetone were preferred for the demonstration of secretory IgA. Extravascular IgG was shown to be still soluble after fixation and capable of being removed from the tissue. The demonstration of IgM in intestinal crypt epithelium is reported and its possible role as a secretory antibody acting in concert with IgA is discussed.

Intestinal secretion of immunoglobulins and antibodies to Escherichia coli in the pig

Immunoglobulins and antibodies against Escherichia coli 0141 have been studied in porcine intestinal secretions obtained from Thiry Vella loops prepared in the mid jejunum of 4 animals.

The molecular size of the secreted immunoglobulins were investigated by gel filtration and sucrose density gradient ultra-centrifugation. Intestinal IgM was found to have 7S characteristics and intestinal IgA mainly 11S characteristics similar to secretory IgA isolated from porcine milk.

Immune inhibition studies with rabbit anti-IgA-globulin serum produced complete elimination of E. coli 0141 antibodies detected by direct haemagglutination. In one animal incomplete antibody assayed by antiglobulin haemagglutination was identified in fractions associated with IgM and IgG.

Immunofluorescent studies were made to correlate immunoglobulins in the small intestinal tissue with weaning.

Secretory IgA and antibodies to Escherichia coli in porcine colostrum and milk and their significance in the alimentary tract of the young pig

Specific antisera prepared in rabbits against porcine immunoglobulins have been used in the measurement of IgG, IgA and IgM in porcine colostrum and milk throughout the first weeks of lactation. The immunoglobulins account for more than 60 per cent of the colostral whey protein and approximately 80 per cent of the immunoglobulin is IgG. During the first 2–3 days of lactation IgG and IgM fall to approximately one-tenth of the original level but IgA shows only a two- to three-fold decrease and becomes the predominant immunoglobulin in sow milk.

Antibodies to Escherichia coli 0141 and 08 antigens were predominantly associated with IgA although IgM is an important antibody in colostrum. Immunofluorescent studies of IgA in mammary tissue provide some evidence for local synthesis.

The passage of sow milk IgA through the alimentary tract was studied in young pigs with re-entrant fistulae prepared in the small intestine. The observations are discussed in relation to the function of IgA as an antibody providing protection in the alimentary tract.

Immunoglobulin IgA in the urine of conventional and colostrum-deprived hypogammaglobulinaemic pigs

Immunoglobulin IgA has been identified in the urine of normal and hypogammaglobulinaemic pigs. Gel filtration studies using Sephadex G-200 indicate that the molecular size of urinary IgA is greater than serum IgA and similar to that of secretory IgA characterized in milk in the 11–18S range. Components having shared antigenic determinants with immunoglobulin IgG appear in the low molecular weight gel filtration peak approximately 1.5S, but 7S IgG could not be detected. In quantitative studies of normal and hypogammaglobulinaemic pigs the urinary ratio IgA/IgG with one exception exceeded the serum ratio. In three out of six urine samples from hypogammaglobulinaemic animals the ratio was greater than unity indicating a preferential excretion of IgA in the urine. The evidence suggests that IgA appears in the urine as a result of tubular secretion and not glomerular filtration. Immunofluorescent studies of the kidney have identified the molecule in the renal tubular epithelium.