Does Threat Have an Advantage After All? - Proposing a Novel Experimental Design to Investigate the Advantages of Threat-Relevant Cues in Visual Processing

The automatic visual attentional procession of threatening stimuli over non-threatening cues has long been a question. The so-called classical visual search task (VST) has quickly become the go-to paradigm to investigate this. However, the latest results showed that the confounding results could originate from the shortcomings of the VST. Thus, here we propose a novel approach to the behavioral testing of the threat superiority effect. We conducted two experiments using evolutionary relevant and modern real-life scenes (e.g., forest or street, respectively) as a background to improve ecological validity. Participants had to find different targets in different spatial positions (close to fovea or periphery) using a touch-screen monitor. In Experiment 1 participants had to find the two most often used exemplar of the evolutionary and modern threatening categories (snake and gun, respectively), or neutral objects of the same category. In Experiment 2 we used more exemplars of each category. All images used were controlled for possible confounding low-level visual features such as contrast, frequency, brightness, and image complexity. In Experiment 1, threatening targets were found faster compared to neutral cues irrespective of the evolutionary relevance. However, in Experiment 2, we did not find an advantage for threatening targets over neutral ones. In contrast, the type of background, and spatial position of the target only affected the detection of neutral targets. Our results might indicate that some stimuli indeed have an advantage in visual processing, however, they are not highlighted based on evolutionary relevance of negative valence alone, but rather through different associational mechanisms.

Increased expression of intercellular adhesion molecule-1 and mucosal adhesion molecule alpha4beta7 integrin in small intestinal mucosa of adult patients with food allergy

The mechanisms of adverse reactions to foods in the gastrointestinal tract are poorly understood. Previous studies of other atopic diseases and animal models suggest that adhesion molecules and mucosal lymphocytes may be implicated in the pathogenesis of food allergy (FA). The aim of our study was to investigate the expression of adhesion molecules and mucosal lymphocytes in duodena of patients with food allergies and of controls. Ten patients with FA to cereals (wheat, oats, and rye) or cow's milk and 9 control patients were included in the study. Quantitative analysis and immunohistochemical stainings for two pairs of adhesion molecules (intercellular adhesion molecule-1 (ICAM-1), lymphocyte function-associated antigen-1 (LFA-1), alpha4beta7 integrin, and mucosal addressin cell adhesion molecule (MAdCAM-1) and lymphocyte markers on endoscopic duodenal biopsy specimens were performed. The villous structure and density of LFA-1-positive cells were normal in every biopsy specimen, but the patients had significantly more alpha4beta7+ cells in the intraepithelial space (P = 0.01). The expression of ICAM-1 in the lamina propria of patients with FA was also substantially increased (P = 0.003); however, staining with MAdCAM showed no intergroup difference. Moreover, we found significantly increased CD4+ and HLA-DR+ cells in the lamina propria of patients, in comparison to the controls, P = 0.05 and P = 0.04, respectively. The densities of CD3, CD8, HLA-DP, T cell receptor alphabeta+ and gammadelta+ cells and IgA-, IgA1-, and IgA2-containing cells did not differ in the two groups studied. Our results suggest that the increased expression of ICAM-1 and alpha4beta7 integrin may play an important role in the pathogenesis of food hypersensitivity and with the elevation of CD4- and HLA-DR-positive cells reflect a stage of inflammation in the structurally normal intestines.

Jejuna of patients with insulin-dependent diabetes mellitus (IDDM) show signs of immune activation

The roles of enteric viruses and food antigens as possible triggers in human insulin-dependent diabetes mellitus and the evidence that mucosal-associated homing receptors are important in both human and experimental diabetes prompted us to undertake an immunohistochemical study of intestinal specimens from patients with IDDM. We studied jejunal morphology and immunohistochemistry in 26 patients with IDDM, 13 of whom had the HLA-DQB1*0201 gene and therefore a higher risk of coeliac disease. The findings were compared with those in specimens from age-matched controls. Villous structure and the density of the intraepithelial lymphocytes were normal in every biopsy specimen. The extent of positivity with anti-DR and -DP antibodies in the villous epithelium was significantly greater in the specimens from patients than in those from controls (P = 0.0002 in both comparisons). The crypts were also more positive: for DR P = 0.0001, and for DP P = 0.002. The densities of T cells, CD4+, CD8+, and T cell receptor alpha/beta+ and gamma/delta+ cells in the epithelium and lamina propria were similar in patients and controls, but the patients had significantly more alpha 4/beta 7 integrin+ cells in the lamina propria (P = 0.006). No difference was seen between HLA-DQB1*0201-positive and -negative patients. These findings reflect a stage of inflammation in the structurally normal intestines of patients with IDDM and suggest secretion of inflammatory Th1-type cytokines in the intestine.

Density of gamma/delta+ T cells in the jejunal epithelium of patients with coeliac disease and dermatitis herpetiformis is increased with age

Increased density of gamma/delta T cell receptor (TCR)+ intraepithelial lymphocytes is the only characteristic in the jejunum of patients with coeliac disease and dermatitis herpetiformis which is not normalized on a gluten-free diet. We explored the age-dependent changes in intraepithelial gamma/delta and alpha/beta TCR+ cells from 137 biopsies from patients with coeliac disease and dermatitis herpetiformis and from controls. Biopsy specimens from 100 patients with coeliac disease and dermatitis herpetiformis and from 37 controls were studied with an immunohistochemical method using MoAbs to T cell receptors and peroxidase staining. An increase in the density of intraepithelial gamma/delta T cells above the mean +2 s.d. of the density in controls was present in 97 of 100 specimens from patients with coeliac disease and dermatitis herpetiformis. The density of gamma/delta+ cells of patients with coeliac disease and dermatitis herpetiformis on a normal gluten-containing diet showed a positive correlation with age (r = 0.45, P < 0.0001). In controls, the density of gamma/delta+ cells remained low throughout the age-range studies, from age 0.6-57 years. In controls, alpha/beta+ cells increased with age (r = 0.57, P < 0.001). The increase in density of intraepithelial lymphocytes with age is in agreement with their thymus-independent character and local proliferation.

Immunohistochemical findings in jejunal specimens from patients with IgA deficiency

Jejunal biopsy specimens from 25 patients with IgA deficiency (IgAd) were studied immunohistochemically to find markers of inflammation. Five of the 25 patients had coeliac disease (CD): they were on a gluten free diet and had normal jejunal morphology. Only two of 15 specimens from control subjects had CD25+ cells in the surface epithelium, while this was seen in 19 out of 20 specimens from IgAd patients (p < 0.0001). A significant increase of CD25+ cells was also noted in the lamina propria of IgAd patients. The median percentage of crypt cells in mitosis (Ki67+ cells) was higher in the specimens from IgAd patients (26%) than in those from controls (13%, p < 0.001). The densities of gamma delta T cell receptor positive cells in the surface epithelium and lamina propria did not differ in the specimens from IgAd patients and those of controls nor was the expression of HLA class II antigens augmented in the surface epithelium. These findings were similar for the IgAd patients whether or not the patient had DQB 0201 allele, a genetic marker which is strongly associated with CD. The inadequacy of the local immunoglobulins in patients with IgAd may lead to increased T cell activation, which is accompanied by the appearance of intraepithelial CD25+ cells and with an increase in the mitotic rate in the crypts.

Crypt hyperplasia related to increased lymphocyte activation in the rectal mucosa of children with ulcerative colitis

The presence of cells positive for interleukin-2 receptors (CD25) and the proportion of Ki-67 positive dividing cells in the crypts were studied with monoclonal antibodies using sensitive immunohistochemical techniques in the rectal biopsy specimens taken from 13 children with inflammatory bowel disease (4 Crohn's disease and 9 ulcerative colitis) and 10 controls. In all specimens, but one, from patients CD25+ cells were found in the surface and crypt epithelium, while in none of controls were seen such cells. The mean percentage of dividing crypt cells was significantly higher in ulcerative colitis (36.0%) and in Crohn's disease (34.6%) than in controls (18.4) (p < 0.001 in both comparisons). In ulcerative colitis, a correlation between CD25/CD3 ratios in the surface and crypt epithelium and the percentage of dividing crypt cells was found. We conclude that activated lymphocytes have a role in the crypt hyperplasia of ulcerative colitis.

Elderly care. Automatic implantable cardioverter defibrillators

The automatic implantable cardioverter defibrillators (AICD) is a commonly accepted treatment for an increasing number of elderly clients at high risk for ventricular dysrhythmias and sudden cardiac death. With increasingly successful use of AICDs, a unique group of gerontological patients has emerged with special physical, educational, psychosocial, and emotional needs. Gerontological nurses will encounter these clients in acute care settings as well as in home health care, nursing homes, senior citizen centers, and adult day health-care centers. Nurses need basic information about AICDs to plan for the continued care, teaching, guidance, and reassurance of these clients and their families.

Intestinal gamma/delta receptor-bearing T lymphocytes in celiac disease and inflammatory bowel diseases in children. Constant increase in celiac disease

We studied the numbers of T-cell receptor alpha/beta- and gamma/delta-bearing lymphocytes in 27 jejunal specimens from 19 celiac patients, 27 rectal and colonic specimens from 14 ulcerative colitis patients and four patients with Crohn's disease, and 24 control specimens. MAb and a three-layer peroxidase staining method were used. Only low numbers of gamma/delta + cells were seen in normal jejunum and rectum of controls, as well as in the specimens of patients with inflammatory bowel diseases. In the lamina propria of celiac patients, the mean number of gamma/delta + cells was significantly higher than in the controls before treatment, during gluten-free diet, and after the gluten challenge. Within the jejunal epithelium, the number of gamma/delta + cells was elevated before and during gluten elimination and after the challenge test. The absolute number of intraepithelial gamma/delta + cells remained constant during gluten elimination and provocation. We infer that the constantly elevated population of gamma/delta + T cells in the epithelium of celiac patients may play an important role in the pathogenesis of celiac disease.

IgG3 and IgG4 cells are increased in active ulcerative colitis

Cells containing various subclasses of IgG and IgA were counted in the rectal and colonic mucosae from 14 pediatric patients with ulcerative colitis (UC) and in rectal biopsy specimens from 10 control subjects using monoclonal antibodies and the peroxidase-staining method. In both the patients and controls, the IgG1 cells predominated. The numbers of IgG1, IgG2, IgG3 and IgG4 cells were highest in the colonic specimens of patients with UC. The numbers of IgG3- and IgG4-containing cells were increased in the rectal mucosa of untreated UC patients compared to controls. In the rectal mucosa of patients with UC, the percentage of IgG2 cells was decreased compared to the controls (20 vs. 28%; p less than 0.05). In the great majority (37 out of 40) of specimens the number of IgA1 cells was higher than that of IgA2. The median number of IgA1 cells in the rectal specimens of untreated patients was slightly higher than that in the rectal specimens of the controls, for IgA2 the numbers were similar. Accentuation of colorectal IgG3 and IgG4 responses may be characteristic early changes in UC.

HLA-DR expression, natural killer cells and IgE containing cells in the jejunal mucosa of coeliac children

The expression of HLA-DR by surface and crypt epithelium and the numbers of cells of natural killer (NK) phenotype and of IgE containing cells were studied with monoclonal antisera using the peroxidase technique. We examined 48 jejunal biopsy specimens taken from 35 coeliac children before treatment (11), during gluten free diet (20) and after gluten challenge (17), and 13 control specimens. The luminal surface of the epithelial cells stained with HLA-DR antiserum in all specimens, but the cytoplasm of the surface epithelial cells took up the stain more frequently in the specimens from the controls (5/13) than those from the coeliacs (2/48) (p less than 0.01). In 21/28 specimens taken from coeliacs when on a gluten containing diet the crypt epithelium showed strong HLA-DR expression, while only 4/20 (p less than 0.01) specimens of coeliacs on a gluten free diet and 1/13 specimens of controls had similar staining. Among the intraepithelial lymphocytes no cells of NK phenotype were found in specimens from patients or controls. As compared with control specimens biopsy specimens from untreated coeliac patients showed smaller numbers of NK cells in the lamina propria. No difference was found in the numbers of IgE containing cells between the patients and controls. The strong expression of HLA-DR by the crypt epithelial cells in coeliac children on a normal diet suggest that these cells are involved in the presentation of the antigen.