Learning Process During Risk Detection in Adolescents With ADHD

OBJECTIVE

To evaluate and describe the performance during the learning process of risk-detection versus risk-benefit processing in adolescents diagnosed with ADHD.

METHOD

Thirty-five adolescents with ADHD and 26 paired controls participated. The tests applied are Iowa-type children version paradigm and Stroop test.

RESULTS

Adolescents with ADHD exhibited lower risk-benefit processing capacity and lower ability to detect risk selections; main findings also indicate that adolescents with ADHD were slower to learn to avoid risk choices. In addition, they also presented a deficient inhibitory control.

CONCLUSION

Results confirm the presence of a deficit in advantageous choice in adolescents with ADHD. By providing a measure of risk choice-and not only a net score-we show that adolescents with ADHD also fail to avoid risk choices. This deficit is mainly because they are slower in learning how to avoid risk choices, and not simply deficient. Literature is scarce concerning studies with Iowa-type paradigms in samples intregated exclusively by adolescents. More research is needed to clarify the nature of these deficiencies.

[Disseminated acute encephalomyelitis in children]

INTRODUCTION

Disseminated acute encephalomyelitis (DAE) is an autoimmune inflammatory condition, usually monophasic with gradual resolution, polysymptomatic, usually in relation to a virus, bacteria or immunizations but may also occur in the absence of any obvious infection.

OBJECTIVE

To describe DAE, its aetiology, clinical features, diagnosis and treatment. Also to analyze these aspects with regard to a series of 13 children with DAE.

RESULTS

The clinical condition started with fever in 61% of the patients. The commonest neurological findings were sensory deterioration, convulsions and motor disorders (paresias). The cerebrospinal fluid was abnormal in four patients. MR showed hyperintense lesions of multifocal distribution, predominantly in the subcortical white matter. All patients were treated with intravenous methylprednisolone at a dose of 20 30 mg/kg. Clinical follow up showed complete recovery in 11/13 patients and mild sequelae in two cases.

CONCLUSIONS

Diagnosis of DAE is based on suggestive clinical data and MR findings. MR is very sensitive in detecting demyelinating lesions and is the method of choice for confirmation of the diagnosis. DAE is characterized by a satisfactory clinical course with simultaneous resolution of the demyelinating lesions.

Synthesis of phosphatidyl-dCMP in human lymphocytes and its enhancement by chlorpromazine

When phytohemagglutinin-stimulated lymphocytes are labelled with [3H]deoxycytidine (dCyd), a compound soluble in organic solvents is formed. Several analytical procedures such as thin-layer chromatography and alkaline hydrolysis of the product obtained after labeling of stimulated lymphocytes with [14C]glycerol and [3H]dCyd, suggest that the product synthesized is phosphatidyl-dCMP. This compound is synthesized in much smaller amounts than when permeabilized lymphocytes and [3H]dCTP as a precursor are used. The synthesis of phosphatidyl-dCMP is highly enhanced by chlorpromazine, phosphatidic acid and arachidonic acid, whereas addition of inositol diminishes the amount of detected phosphatidyl-dCMP. It is suggested that this compound would be a precursor of phosphatidylinositol.

Synthesis of phosphatidly-dCMP in permeabilized normal human lymphocytes

When peripheral lymphocytes stimulated with phytohemagglutinin were permeabilized in vitro, (3H) dCTP acted as a precursor for DNA synthesis, but the formation of a compound soluble in organic solvents could also be demonstrated. The structure of the latter compound was studied analyzing the products formed after alkaline hydrolysis or an enzymatic treatment with nucleotide pyrophosphatase. Both treatments led to the formation of (3H)dCMP. When stimulated lymphocytes were labeled in vivo with (14C)glycerol before permeabilization and ulterior labeling with (3H)dCTP a double labeled compound was obtained. When this compound was submitted to alkaline hydrolysis, (3H)dCMP and (14C)glycerol-3-phosphate were obtained. It was concluded that the compound soluble in organic solvents was phosphatidyl-dCMP.

Synthesis of DNA in human lymphocytes: possible control mechanism

Partially purified, isolated nuclei from lymphocytes either stimulated or not stimulated by phytohemagglutinin can equally well synthesize DNA when [(3)H]dTTP is used as precursor. Studies of DNA polymerase activity in nuclei and cytoplasm from these cells showed that the enzyme can be detected in either stimulated or nonstimulated lymphocytes. In nonstimulated lymphocytes the uptake of thymidine is very low. The use of inhibitors such as cycloheximide, arbinosylcytosine, and actinomycin D showed that a parallel existed between thymidine uptake and DNA synthesis. All the conditions in which DNA synthesis was inhibited resulted also in an inhibition of thymidine uptake.