The impact of reinforcement contingencies on AD/HD: a review and theoretical appraisal

One of the core deficits in attention deficit/hyperactivity disorder (AD/HD) is thought to be an aberrant sensitivity to reinforcement, such as reward and response cost. Twenty-two studies (N=1181 children) employing AD/HD and reinforcement contingencies are reviewed from vantage points: task performance, motivation, and psychophysiology. Results indicate that reinforcement contingencies have a positive impact on task performance and levels of motivation for both children with AD/HD and normal controls. There is evidence that the effect related to task performance is somewhat more prominent in AD/HD. There is some evidence that a high intensity of reinforcement is highly effective in AD/HD. Children with AD/HD prefer immediate over delayed reward. From a psychophysiological point of view, children with AD/HD seem less sensitive to reinforcement compared to controls. While comorbid disorders are suggested to be confounders of the dependent variables, many studies do not examine the effect of oppositional defiant disorder (ODD) and conduct disorder (CD). We discuss the implications of the findings for five theoretical frameworks, including the model by, the cognitive-energetic model (CEM), the dual-pathway model and the BIS/BAS model. Results show a discrepancy between the theoretical models and the behavioural findings.     

The influence of comorbid oppositional defiant disorder on white matter microstructure in attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) are highly comorbid disorders. ADHD has been associated with altered white matter (WM) microstructure, though the literature is inconsistent, which may be due to differences in the in- or exclusion of participants with comorbid ODD. WM abnormalities in ODD are still poorly understood, and it is unclear whether comorbid ODD in ADHD may have confounded the current ADHD literature. Diffusion Tensor Imaging (DTI) was used to compare fractional anisotropy (FA) and mean diffusivity (MD) between ADHD patients with (n = 42) and without (n = 117) comorbid ODD. All participants were between 8–25 years and groups did not differ in mean age or gender. Follow-up analyses were conducted to examine the role of antisocial behaviour (conduct problems) on FA and MD values in both groups. Comorbid ODD in ADHD was associated with lower FA in left frontotemporal WM, which appeared independent of ADHD symptoms. FA was negatively associated with antisocial behaviour in ADHD + ODD, but not in ADHD-only. Comorbid ODD is associated with WM abnormalities in individuals with ADHD, which appears to be independent of ADHD symptoms. Altered WM microstructure in comorbid ODD may play a role in inconsistencies in the current DTI literature in ADHD. Altered development of these tracts may contribute to social-emotional and cognitive problems in children with oppositional and antisocial behaviour.     

青心酮防治ApoE(-/-)小鼠主动脉粥样硬化斑块形成与脂氧素的关系

目的观察青心酮防治ApoE(-/-)小鼠主动脉粥样硬化(AS)病变形成与脂氧素的关系。方法取8只8周龄C57BL/6小鼠作空白对照组;取24只8周龄的ApoE(-/-)小鼠,♂,随机分成3组(每组8只):动脉硬化组(乙醇20 mg kg 1 d 1);青心酮组(青心酮20 mg kg 1 d 1);辛伐他汀组(辛伐他汀20 mg kg 1 d 1)。所有小鼠均以"西方类型膳食"饲养至16周。取血检测脂氧素、血脂和15-脂氧合酶蛋白的含量等;取主动脉根部行HE染色观察ApoE(-/-)主动脉粥样硬化病变情况;电镜观察斑块内皮细胞变化。Western blotting法测定血清中15-LO水平。结果青心酮组脂氧素增加,血脂含量降低,AS病灶形成减少,斑块内皮细胞损伤减轻,15-脂氧合酶含量减少。结论青心酮防治ApoE(-/-)小鼠AS病变,可能与其增加15-脂氧合酶途径产物——脂氧素有关。     

Interferon system status in hemodialysis patients infected with hepatitis B and C viruses]

The production of alpha- and gamma-interferon (IFN) by peripheral blood cells in vitro and the concentration of serum IFN were studied in patients treated by hemodialysis at the Pelgulinna Tallinn Hospital and compared to controls. Out of 108 patients on hemodialysis, 19.4% were infected with hepatitis B (HBV), and antibodies to hepatitis C virus (HCV) were detected in 7.4%. During 3.5 years of observation, cases of hepatitis B and C infection among patients and medical staff were rare. The production of alpha- and gamma-IFN in 23 patients with HBV and/or HCV markers on hemodialysis and in 38 patients without markers was similarly decreased in comparison with the controls and the titers of serum IFN were similarly increased. Lack of reliable difference between IFN status of two groups of patients may be explained by the absence of clinical symptoms of hepatitis, confirmed by laboratory findings.     

Early referral and planned initiation of dialysis: what impact on quality of life?

BACKGROUND: Early patient referral correlates with improved patient survival on dialysis. We examine whether early referral and a planned first dialysis affect quality of life (QoL). METHODS: All patients commencing dialysis in nine centres in seven European countries between 1 July 1998 and 31 October 1999 were recruited. Definitions: early referral=followed by a nephrologist >1 month before first dialysis (<1 month=late referral); planned=early referral and previous serum creatinine >300 micro mol/l and non-urgent first dialysis (early referral and no creatinine >300 micro mol/l or urgent first dialysis=unplanned). QoL was measured at 8 weeks using a visual analogue scale (VAS) and Short Form 36 (SF-36). RESULTS: VAS was significantly higher in early referral patients [mean (SD) 58.4 (20) vs 50.4 (19), P=0.005], particularly if the first dialysis was planned [60.7 (20) vs 54.2 (20), P=0.03]. Planned patients also had higher SF-36 mental summary scores [45.4 (12) vs 39.7 (11), P=0.003], role emotional scores [58.0 (43) vs 30.9 (38), P=0.003], and mental health scores [63.7 (24) vs 54.6 (22), P=0.01] than unplanned patients. Adjusting for centre and other confounding variables showed that having a planned first dialysis had an independent effect on QoL (VAS, and the SF-36's mental summary score, physical functioning, role physical, general health, role emotional and mental health). Early referral had no independent effect on QoL. Socio-economic status had an important positive effect on physical QoL. CONCLUSIONS: While the effect of early referral to a nephrologist on QoL appeared centre dependent, a smooth transition onto dialysis was associated with significantly better early QoL, independent of other variables.     

Clinical characteristics of ulcerative colitis in Singapore,a multiracial city-state

BACKGROUND: Ulcerative colitis (UC) is rare in Asia. Singapore is an ethnically heterogeneous city-state with a population made up of Chinese (77%), Indians (7.5%), and Malays (14%). This study describes and compares the characteristics of Chinese, Malay, and Indian patients with UC. STUDY: Retrospective chart review was performed of 235 patients seen in the largest tertiary care hospital in Singapore between 1971 and June 2000. RESULTS: There were 169 (72%) Chinese, 24 (10%) Malays, and 42 (18%) Indians with UC. Male-to-female ratio was 1.8:1 (150:85). Most patients in all three races presented between the ages of 20 and 39 years. No bimodal peak in the age at presentation was seen. The median period from onset of symptoms to diagnosis was 1 month in all three races. More Malay (57%) and Indian (55%) patients had colitis extending proximal to splenic flexure at presentation compared with Chinese (32%) patients (p = 0.04). There were more Indian patients (29%) with severe disease at onset compared with Chinese (12%) and Malay (22%) patients (p = 0.035). Thirty-one percent of patients had only one episode of colitis, 12% were steroid dependent, and 4% were steroid refractory. Proctocolectomy was needed in 31 (18.3%) Chinese, 3 (12.5%) Malay, and 4 (9.5%) Indian patients. Extraintestinal manifestations were found in 6% of the Chinese, 12% of Malay patients, and 14% of Indian patients. The most common extraintestinal manifestation was arthritis, present in 6.4% of patients. CONCLUSION: There were more Indians with UC than expected in this population. Whereas Indian and Malay patients have more extensive and severe disease at presentation than Chinese patients, this does not predict for more refractory disease or a greater need for surgery.