Functionality of the pneumococcal antibody response in Down syndrome subjects.

We investigated the anti-polysaccharide antibody responses in subjects with Down syndrome (DS) because DS subjects show decreased peripheral B-lymphocyte numbers in all age groups, and a clinical picture of recurrent respiratory tract infections and increased incidence of autoimmune diseases which is reminiscent of common variable immunodeficiency disorders (CVID)-like disease. We determined titers and opsonophagocytosis in response to conjugated and unconjugated pneumococcal serotypes in 18 DS subjects aged 6-24 years. The results show adequate serotype-specific antibody titers in response to all conjugated and almost all unconjugated serotypes used. Opsonophagocytosis activity as measured against pneumococcal serotypes 9N, 19F and 23F was also found to be intact. We conclude that DS subjects do not have a clear defect in their anti-polysaccharide antibody response.

Differential effects of 7-OH-DPAT on amphetamine-induced stereotypy and conditioned place preference.

Low doses of the dopamine D3-preferring agonist 7-hydroxy-N,N-di-n-propyl-2-aminotetralin (7-OH-DPAT) produce a behavioral profile that is opposite to that produced by the psychomotor stimulants cocaine and amphetamine. For example, low doses of 7-OH-DPAT produce conditioned place aversion and hypolocomotion, whereas psychomotor stimulants produce conditioned place preference (CPP) and hyperlocomotion. In experiment 1, the effects of low doses of 7-OH-DPAT (0.01-0.1 mg/kg) on d-amphetamine-induced (1 mg/kg) motor behaviors and CPP were assessed. In experiment 2, the effects of 0.1 mg/kg 7-OH-DPAT on d-amphetamine (0-10 mg/kg) dose-response curves for the same behaviors were examined. During conditioning, drug injections were paired with a distinct compartment, whereas saline injections were paired with another compartment. Locomotion and headbobbing were measured following acute and repeated drug administration during conditioning and place conditioning was assessed 24 h following the last conditioning day. In experiment 1, d-amphetamine-induced locomotion was dose-dependently decreased by 7-OH-DPAT following repeated administration, which was probably due to the emergence of headbobbing, a behavior not observed with d-amphetamine alone. d-Amphetamine-CPP was not altered by co-administration of 0-0.03 mg/kg 7-OH-DPAT, but was attenuated by co-administration of 0.1 mg/kg 7-OH-DPAT. In experiment 2, 7-OH-DPAT co-administered with low doses of d-amphetamine (0-0.5 mg/kg) produced a decrease in locomotion following acute administration. However, 7-OH-DPAT produced sensitization of locomotion at the 0.5 mg/kg dose of d-amphetamine and an increase in headbobbing at the 0.5-10 mg/kg doses of d-amphetamine following repeated administration. In contrast, d-amphetamine-CPP was attenuated by co-administration of 7-OH-DPAT. These findings suggest that 0.1 mg/kg 7-OH-DPAT attenuates the reinforcing effects of d-amphetamine despite enhancing stereotypic behaviors.

An automatic prompting instrument to increase task-related responding in low-functioning individuals.

The present study was aimed at developing and assessing an automatic prompting instrument with three multihandicapped students who showed breaks in performance. The effects of the instrument were compared with the effects of manual prompting with simple tasks involving locomotion. The results indicated that manual and instrument prompting were both successful in reducing the amount of time spent in breaks. The effects of the instrument were replicated within subjects. The same effects were still visible during a follow-up assessment. The reliability and durability of those effects as well as the practical implications of automatic prompting are discussed.