War and public health in democratic Republic of Congo.
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Biomedical subjects
Publications and source records attributed to E Schouten.
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The current study examined the anxiety sensitivity construct in a large sample of normal Dutch adolescents aged 13-16 years (n=819). Children completed the Childhood Anxiety Sensitivity Index (CASI; Silverman, W. K., Fleisig, W., Rabian, B. & Peterson, R. A. (1991). Journal of Clinical Child Psychology, 20, 162-168) and measures of trait anxiety, anxiety disorder symptoms and depression. Results showed that (1) anxiety sensitivity as indexed by the CASI seems to be a hierarchically organized construct with one higher-order factor (i.e., anxiety sensitivity) and three or four lower-order factors, (2) anxiety sensitivity and trait anxiety were strongly correlated, (3) anxiety sensitivity was substantially connected to symptoms of anxiety disorders (in particular of panic disorder and agoraphobia) and depression, and (4) anxiety sensitivity and trait anxiety both accounted for unique proportions of the variance in anxiety disorder symptoms. Altogether these findings are in agreement with those of previous research in adult and child populations, and further support the notion that anxiety sensitivity should be viewed as an unique factor of anxiety vulnerability.
RATIONALE AND OBJECTIVES: The authors performed this study to assess the performance of a computer-based classification system that uses gaze locations of observers to define the subspace for machine learning. MATERIALS AND METHODS: Thirty-two dental radiographs were classified by an expert viewer into four categories of disease of the periapical region: no disease (normal tooth), mild disease (widened periodontal ligament space), moderate disease (destruction of the lamina dura), and severe disease (resorption of bone in the periapical area). There were eight images in each category. Six observers independently viewed the images while their eye gaze position was recorded. They then classified the images into one of the four categories. A sample of image space was used as input to a machine learning routine to develop a machine classifier. Sample space was determined with three techniques: visual gaze, random selection, and constrained random selection. K analyses were used to compare classification accuracies with the three sampling techniques. RESULTS: With use of the expert classification as a standard of reference, observers classified images with 57% accuracy, and the machine classified images with 84% accuracy by using the same gaze-selected features and image space. Results of kappa analyses revealed mean values of 0.78 for gaze-selected sampling, 0.69 for random sampling, 0.68 for constrained random selection, and 0.44 for observers. The use of sample space selected with the visual gaze technique was superior to that selected with both random-selection techniques and by the observers. CONCLUSION: Machine classification of dental images improves the accuracy of individual observers using gaze-selected image space.
This study examined the structure of negative emotions in a sample of nonclinical adolescents, using an approach that exclusively relied on child self-report. A large sample of adolescents (N = 968) completed self-report questionnaires measuring symptoms of fear, anxiety, and depression. Confirmatory factor analysis provided support for the notion that fear, anxiety, and depression are distinct yet correlated components of negative emotions. This result is in agreement with recent empirical findings and current theoretical notions on the structure of negative emotions in children and should be taken as an encouragement for researchers to develop more specific measures for assessing fear, anxiety, and depression in children.
Low-fat diets, in which carbohydrates replace some of the fat, decrease serum cholesterol. This decrease is due to decreases in LDL-cholesterol but in part to possibly harmful decreases in HDL-cholesterol. High-oil diets, in which oils rich in monounsaturated fat replace some of the saturated fat, decrease serum cholesterol mainly through LDL-cholesterol. We used these two diets to investigate whether a change in HDL-cholesterol would change flow-mediated vasodilation, a marker of endothelial function. We fed thirty-two healthy volunteers two controlled diets in a weeks' randomised cross-over design to eliminate variation in changes due to differences between subjects. The low-fat diet contained 59.7 % energy (en%) as carbohydrates and 25.7 en% as fat (7.8 en% as monounsaturates); the oil-rich diet contained 37.8 en% as carbohydrates and 44.4 en% as fat (19.3 en% as monounsaturates). Average (sd) serum HDL-cholesterol after the low-fat diet was 0.21 (sd 0.12) mmol/l (8.1 mg/dl) lower than after the oil-rich diet. Serum triacylglycerols were 0.22 (sd 0.28) mmol/l (19.5 mg/dl) higher after the low-fat diet than after the oil-rich diet. Serum LDL and homocysteine concentrations remained stable. Flow-mediated vasodilation was 4.8 (SD 2.9) after the low-fat diet and 4.1 (SD 2.7) after the oil-rich diet (difference 0.7 %; 95 % CI -0.6, 1.9). Thus, although the low-fat diet produced a lower HDL-cholesterol than the high-oil diet, flow-mediated vasodilation, an early marker of cardiovascular disease, was not impaired.
Solid fats are used in food manufacturing to provide texture and firmness to foods. Such fats are rich in either saturated or trans-fatty acids, both of which increase the risk of coronary heart disease. Epidemiological and experimental studies suggest that trans-fatty acids increase risk more than do saturates because they lower serum high density lipoprotein (HDL) cholesterol. However, there appear to be differences between saturates in their effect on HDL cholesterol. We investigated whether the consumption of a solid fat rich in lauric acid (C12:0) would result in a more favorable blood lipid profile than the consumption of a solid fat rich in trans-fatty acids. We fed 32 healthy men and women two controlled diets in a 2 x 4-wk randomized crossover design. The diets consisted of a background diet supplemented with margarines. In the trans-diet, 9.2% of energy was provided by trans-fatty acids and 12.9% by saturated fatty acids. In the Sat-diet, energy intake was 0% from trans-fatty acids and 22.9% from saturated fatty acids. Lauric acid composed one third of all saturates in the Sat-diet. Serum HDL cholesterol was 0.36 mmol/L lower at the end of the trans-diet than at the end of the Sat-diet (95% confidence interval, -0.46 to -0.26), whereas serum low density lipoprotein cholesterol and triglyceride concentrations remained stable. Serum total cholesterol was 0.31 mmol/L (95% confidence interval, -0.48 to -0.14) lower at the end of the trans-diet than at the end of the Sat-diet. Consumption of a solid fat rich in lauric acid gives a more favorable serum lipoprotein pattern than consumption of partially hydrogenated soybean oil rich in trans-fatty acids. Thus, solid fats rich in lauric acids, such as tropical fats, appear to be preferable to trans-fats in food manufacturing, where hard fats are indispensable.
Little is known about the nature of the depressive symptomatology preceding myocardial infarction (MI). Specification of the depressive symptomatology is important for the development of hypotheses about the biological mechanisms relating depressive symptoms to MI. To test the hypothesis that feelings of fatigue and loss of energy have the strongest predictive power of all depressive symptoms, the authors reanalyzed data from a prospective study of 3877 healthy men aged 40 to 65 years. The men's mental state was assessed using the Maastricht Questionnaire, a scale that measures vital exhaustion, which is characterized by unusual fatigue and lack of energy, increased irritability, and depressive symptoms, including demoralization. Oblique factor analysis was used to validate these dimensions. Results of Cox's regression analyses showed that the fatigue subscale has the strongest predictive power for incident MI and that depression and irritability subscales lose their predictive power when controlled for fatigue.
OBJECTIVE: Although self-esteem and overconcern with body shape and weight are considered to be closely connected in bulimia nervosa, little empirical research has been done to investigate the alleged link. METHOD: In this study, we examined experimentally whether overconcern with body shape and weight was connected with self-esteem in an analogue sample of high restrained eaters by means of a subliminal lexical decision task. RESULTS: It could indeed be demonstrated that low self-esteem and overconcern with body shape and weight are associated in high restrained eaters: after priming low self-esteem, the accessibility of subliminally presented body shape and weight stimuli was increased. The effect was not found with a supraliminal lexical decision task. DISCUSSION: Apparently, the automatic, nonconscious processing of body shape and weight words was influenced in high restrained eaters with a low state self-esteem, whereas the strategic, conscious processing was not. As soon as the body shape and weight stimuli were processed consciously, the initial increased accessibility was countered and the effect disappeared.
A fat-rich meal increases activated factor VII (FVIIa), but it is not clear whether this increase depends on the fatty acid composition of the meal. Therefore, we studied the FVIIa response to fat-rich meals with different fatty acid composition in a randomized controlled crossover trial and investigated whether this response is mediated by an increase in serum triglycerides. Elderly women (> 60 years, n=91) received on separate days four different fat-rich breakfasts (50 energy percent [en%] of fat) and a control breakfast (1.5 en% fat; crossover). The fat-rich breakfasts differed in fatty acid composition: one rich in palmitic acid (21.7 g), one in stearic acid (18.6 g), and the other two in linoleic and linolenic acid-one with a ratio 3:1 (12.5/3.9 g) and the other with a ratio of 15:1 (18.8/1.2 g). At 8 AM before the breakfast (fasting) and at 1 and 3 PM, blood samples were taken, in which FVIIa and serum triglycerides were measured. FVIIa response to the fat-rich meals ranged from 11.6 mU/mL (95% confidence interval: 8.3,14.9) on the stearic meal to 15.9 mU/mL (12.0,19.8) on the linoleic/linolenic 15:1 meal at 1 PM and from 14.9 mU/mL (10.6,19.2) to 21.1 mU/mL (16.6,25.6) for the same meals at 3 PM. The responses did not differ between the fat-rich meals. After the control breakfast, FVIIa decreased, with 6.3 mU/mL (3.9,8.7) at 1 PM and 8.7 mU/mL (6.3,11.1) at 3 PM. The triglyceride response was lower after both linoleic/linolenic rich breakfasts compared with the palmitic and stearic breakfast (P<.05) and was not associated with the FVIIa response at any of the blood sampling occasions. The results of this study show that the response of FVIIa to a fat-rich meal is independent of its fatty acid composition and is not mediated by serum triglycerides.
Confirmatory factor analyses were done in an attempt to replicate the factor structure of the Aggression Questionnaire constructed by Buss and Perry (1992) [Journal of Personality and Social Psychology, 63, 452-459] in a Dutch sample. The findings indicated that the Buss and Perry 4-factor model provided a poor fit to the full 29-item questionnaire. Although generally confirming the 4-factor structure, subsequent analyses revealed that a better fit was obtained by omitting 3 items (1 Verbal Aggression and 2 Hostility items). In general, the present findings are rather similar to previous research and emphasize the importance of assessing not only overall aggression but also its separate components.
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In order to test the hypothesis that low levels of endogenous opioids (endorphins) predispose to strong conditioning effects, female Ss (N = 36) were assigned to a placebo group, a low-dose naltrexone group, or a high-dose naltrexone group and then underwent a classical conditioning procedure. This procedure consisted of an acquisition phase in which all Ss received 5 pairings of a CS+ (neutral picture) and a UCS (100 dB white noise). The CS- (neutral picture) was never followed by a UCS. During extinction, Ss received 4 unreinforced presentations of CS+ and CS-. Throughout the experiment, skin conductance responses (SCRs) to the CSs and UCSs were recorded. Acquisition was successful in that CS+ slides elicited stronger SCRs than CS- slides. However, during acquisition, there was no interaction between drug and differential response (CS+ vs CS-). During extinction, there was no overall remaining effect of conditioning. Again, no evidence was found to suggest that (remaining) effects of conditioning were stronger in the naltrexone treated Ss than in the placebo Ss. If anything, the opposite seemed to be true with especially high-dose naltrexone Ss showing relatively weak conditioning effects.
In a prospective study of 3877 males, aged 39-65, the predictive power of complaints indicating problems falling or staying asleep and of the feeling of waking up exhausted was investigated. It was hypothesized that especially those who wake up exhausted but do not complain about problems falling or staying asleep are at increased risk of myocardial infarction. After controlling for age, blood pressure, smoking, cholesterol and the use of anti-hypertensive drugs, the relative risk was found to be 2.74 (95% confidence interval 1.28-5.83) for a years follow-up and 6.50 for the first year of follow-up. These findings indicate that waking up exhausted belongs to the short-term risk indicators of myocardial infarction.
Children with Plasmodium falciparum infections in Western Province, Kenya, were studied in 1987 for their parasitological, clinical and haematological response to chloroquine, to amodiaquine and to pyrimethamine-sulfadoxine plus quinine. Ninety-eight children under 5 years of age were treated in 1 of 2 hospitals. Of the 56 patients treated with chloroquine base 25 mg/kg, 91% had resistant infections, with 36% having no significant decrease in parasitaemia (RIII resistance); however, 69% responded clinically within a week. Of the 27 patients treated with amodiaquine base 25 mg/kg, 67% had resistant infections, with 7% RIII resistant; 81% responded clinically. The parasites cleared in all 15 children given pyrimethamine-sulfadoxine plus 3 days of quinine. Only when parasites cleared did patients have improved haemoglobins and haematocrits. This study shows that parasitaemia in children hospitalized in western Kenya responds poorly to 4-aminoquinolines, although the patients improve clinically, at least during the first 7 days. Young children may need to clear parasites to avoid the risk of severe anemia and the need for blood transfusions.
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During the preparation of a prospective study of exhaustion as a precursor of myocardial infarction (MI), the authors found that many coronary patients said that they had been burned out at some time in their lives. Therefore, the question, "Have you ever been burned out?" was included in the study. The cohort was formed by 3,877 men, aged 39 to 65, and was followed up on for 4.2 years. Among the men who were free of coronary heart disease (CHD) at screening, 59 subjects experienced a fatal or nonfatal myocardial infarction during follow-up. Those who endorsed the above question when they entered the study were found to be at increased risk for myocardial infarction when the authors controlled for age, blood pressure, smoking, and cholesterol; RR (relative risk) = 2.13; p less than .01. About one third of those who were exhausted before myocardial infarction had been burned out at some time in their lives, chi 2 = 7.09, p less than .01. The data indicate that a state of exhaustion before myocardial infarction is often a reactivation of earlier periods of breakdown in adaptation to stress.
In the match/mismatch model, recently formulated by Rachman and coworkers, it is stated that incorrectly predicted aversive experiences are generally followed by an immediate adjustment of the predictions concerning aversiveness of the next experience. This model can be considered to reflect a psychological process of the formation of expectations. In the present article it is argued that a simple H0 model, assuming that predictions are completely randomly generated by the subject, may account for the same effects. This H0 model is used in a stringent test of empirical data to determine if there are any effects of the discrepancy between prediction and experience on next prediction that exceed the effects explained by the H0 model. Although the H0 model produces effects very similar to the empirically observed effects, there is clear support for the hypothesized influence of the discrepancy between prediction and experience. Therefore, the model appears to reflect 'real' psychological processes and not chance findings.