Peer reinforcement control of classroom problem behavior

Peer and teacher interactions with five "disruptive" children were studied in an elementary school classroom. The intent of the study was to analyze experimentally peer reinforcement control of the disruptive children's problem behaviors. Social attention provided by all peers was found to be directed exclusively to the problem behaviors during baseline. Following baseline, several manipulations of selected peer social attention demonstrated the reinforcement function of this stimulus class.

Total-hip arthroplasty: periprosthetic indium-111-labeled leukocyte activity and complementary technetium-99m-sulfur colloid imaging in suspected infection

Indium-111-labeled leukocyte images of 92 cemented total-hip arthroplasties were correlated with final diagnoses. Prostheses were divided into four zones: head (including acetabulum), trochanter, shaft, and tip. The presence (or absence) and intensity of activity in each zone was noted, and compared to the corresponding contralateral zone. Though present in all 23 infected arthroplasties, periprosthetic activity was also present in 77% of uninfected arthroplasties, and was greater than the contralateral zone 51% of the time. When analyzed by zone, head zone activity was the best criterion for infection (87% sensitivity, 94% specificity, 92% accuracy). Fifty of the arthroplasties were studied with combined labeled leukocyte/sulfur colloid imaging. Using incongruence of images as the criterion for infection, the sensitivity, specificity, and accuracy of the study were 100%, 97%, and 98%, respectively. While variable periprosthetic activity makes labeled leukocyte imaging alone unreliable for diagnosing hip arthroplasty infection, the addition of sulfur colloid imaging results in a highly accurate diagnostic procedure.

Delayed biliary-to-bowel transit in cholescintigraphy after cholecystokinin treatment

The authors assessed the influence of cholecystokinin (CCK), administered before cholescintigraphy, on the biliary-to-bowel transit time (BBTT) of technetium-99m disofenin. Fourteen healthy volunteers underwent two separate cholescintigraphic studies with and without CCK treatment. BBTT was less than 1 hour in all 14 studies of subjects not treated with CCK. In 14 subjects treated with CCK, there was no tracer activity in the bowel up to 2 hours in seven (50%) (P = .006). Eighty-three cholescintigrams obtained in patients with suspected acute cholecystitis were also retrospectively analyzed. In 53 of 83 patients in whom the gallbladder was visualized within 1 hour, significantly delayed BBTT was found in 14 of 29 (48%) who received CCK, compared with the BBTT in one of 24 patients (4%) who did not receive CCK (P less than .001). In the 30 patients in whom the gallbladder was never visualized (n = 28) or was visualized after 1 hour (n = 2), BBTT was less than 30 minutes, regardless of whether patients were treated with CCK. Results show that CCK treatment causes significantly delayed BBTT in many cases, and this finding should not be interpreted as abnormal.

Serial dacryoscintigraphy before and after treatment with pseudoephedrine

Radionuclide dacryoscintigraphy is an accurate physiologic method for evaluating the nasolacrimal drainage apparatus. The following case report illustrates the role of this procedure in the initial workup of epiphora, as well as its value in assessing response to therapy with pseudoephedrine.

Effect of patient position on interpretation of lung images complicated by chest radiograph opacities

Lung images in which perfusion defects correspond to chest radiograph (CXR) opacities in size and location are generally classified as having an intermediate probability for pulmonary embolism, while those studies in which the perfusion defects are considerably smaller than the CXR opacities are classified as having a low probability for pulmonary embolism. A case is presented in which, by imaging a patient in both the erect and supine positions, the authors were able to change the interpretation of the study from intermediate probability (perfusion defect = CXR opacity) to low probability (perfusion defect less than CXR opacity).

Detection of abnormalities in febrile AIDS patients with In-111-labeled leukocyte and Ga-67 scintigraphy

Thirty-six patients with acquired immunodeficiency syndrome (AIDS), who were febrile but without localizing signs, underwent indium-111 leukocyte scintigraphy 24 hours after injection of labeled white blood cells (WBCs) and were restudied 48 hours after injection of gallium-67 citrate. Fifty-six abnormalities were identified as possible sources of the fever; 27 were confirmed with biopsy. Of these 27, 15 were identified only on In-111 WBC scans (including colitis, sinusitis, and focal bacterial pneumonia); six, only on Ga-67 scans (predominantly Pneumocystis carinii pneumonia and lymphadenopathy); and six, on both studies (predominantly pulmonary lesions). In-111 WBC scanning revealed 21 of 27 abnormalities (78%) and gallium scanning, 12 of 27 (44%). If only one scintigraphic study has been performed, particularly with Ga-67, a significant number of lesions would not have been detected. The authors believe radionuclide evaluation of the febrile AIDS patient without localizing signs should begin with In-111 WBC scintigraphy. Gallium scanning may be used depending on results of In-111 WBC scans or if there is a high index of suspicion for P carinii pneumonia.