Noninvasive determination of acetaminophen disposition in Down's syndrome.

In this study we evaluated subjects with Down's syndrome for the possibility that direct or indirect gene dosage effects of trisomy 21 alter the fate of acetaminophen. We also investigated the usefulness of noninvasive sampling techniques to obtain parameter estimates for drug disposition in these developmentally disabled individuals. After administration of 5 mg/kg and 20 mg/kg oral doses of acetaminophen, subjects with Down's syndrome resembled control subjects in most pharmacokinetic and metabolic parameters, including apparent half-life, volume of distribution per kilogram body mass, total body clearance per kilogram of body mass, extrapolated saliva concentration at time zero, and the urinary excretion of acetaminophen glucuronide and sulfate conjugates. Glutathione conjugation tended to increase and sulfate conjugation tended to decrease in all subjects as the acetaminophen dose increased from 5 mg/kg to 20 mg/kg. Results based on these samples of very limited size also suggest that acetaminophen metabolism to glutathione-derived conjugates may have been increased in subjects with Down's syndrome. The similarity of estimates of acetaminophen pharmacokinetics and data on metabolic fate between subjects with Down's syndrome and normal volunteers indicates that large effects of trisomy 21 on these processes are unlikely. Also, these results were in agreement with extensive data obtained with invasive techniques, indicating that simple noninvasive methodologies appear to be well suited for studying acetaminophen disposition in populations of developmentally disabled individuals.

Symptomatic atlantoaxial instability associated with medical and rehabilitative procedures in children with Down syndrome.

The Canadian College of Medical Genetics recently questioned the rationale for radiographic screening for atlantoaxial instability in Down syndrome. We report a case series of four children with Down syndrome with symptomatic atlantoaxial instability and followed for more than 5 years. In all cases a medical or rehabilitational procedure was associated with significant apnea, cardiopulmonary compromise, or severe neurological impairments. None of these patients were screened radiographically. The need for protocols to detect atlantoaxial instability in children with Down syndrome undergoing medical and rehabilitational procedures is highlighted by these cases.

Relationships between laterality of congenital upper limb reduction defects and school performance.

Eighty children (34 males, 46 females) with congenital upper limb reduction defects who attended a regional amputee clinic between 1956 and 1986 were classified as to whether they exhibited learning difficulties in school, as indicated by grade failure or by placement in learning disability classrooms. Children with right-sided defects were more likely to encounter learning difficulties than were children with left-sided defects (Chi-square = 6.8; df = 1; p less than 0.01). Children with right-limb defects also were more likely than children with left-limb defects to experience reading problems (Chi-square = 5.9; df = 1; p less than 0.05). These results suggest the need for neuropsychological and neurophysiological study of children with limb reduction defects.

Adult respiratory distress syndrome: radiologic manifestations and course.

During a 36-month period, the serial chest x-ray films of 26 patients with the adult respiratory distress syndrome (ARDS) were evaluated for the patterns of onset, course, and follow-up appearance when possible. An exudative phase appearance can be recognized, which can clear. The exudative phase appearances are (1) a bilateral, homogeneous, white-out alveolar appearance; (2) an asymmetric consolidative appearance; and (3) a central perihilar ("bat-wing") consolidative appearance. This progresses to a proliferative phase manifested on chest x-ray film as an interstitial appearance that must not be confused with fibrosis, as the chest x-ray film may return to normal.