Growth Hormone Protects Against Ovariectomy-Induced Bone Loss in States of Low Circulating Insulin-like Growth Factor (IGF-1)*

Early after estrogen loss in postmenopausal women and ovariectomy (OVX) of animals, accelerated endosteal bone resorption leads to marrow expansion of long bone shafts that reduce mechanical integrity. Both growth hormone (GH) and insulin-like growth factor (IGF-1) are potent regulators of bone remodeling processes. To investigate the role of the GH/IGF-1 axis with estrogen deficiency, we used the liver IGF-1-deficient (LID) mouse. Contrary to deficits in controls, OVX of LID mice resulted in maintenance of cortical bone mechanical integrity primarily owing to an enhanced periosteal expansion affect on cross-sectional structure (total area and cortical width). The serum balance in LID that favors GH over IGF-1 diminished the effects of ablated ovarian function on numbers of osteoclast precursors in the marrow and viability of osteocytes within the cortical matrix and led to less endosteal resorption in addition to greater periosteal bone formation. Interactions between estrogen and the GH/IGF-1 system as related to bone remodeling provide a pathway to minimize degeneration of bone tissue structure and osteoporotic fracture. © 2010 American Society for Bone and Mineral Researc

Treating Excessively Slow Responding of a Young Man With Asperger Syndrome Using Differential Reinforcement of Short Response Latencies

Fjellstedt and Sulzer-Azaroff (1973) used differential reinforcement of short latencies to decrease a child's latency to comply with instructions. We replicated this contingency with a young man diagnosed with Asperger syndrome across two tasks (question answering and math problem solving). We added a differential reinforcement contingency to teach the participant to discriminate between math problems that could be answered rapidly and those that required more time for accurate performance

EVALUATING THE SEPARATE AND COMBINED EFFECTS OF POSITIVE AND NEGATIVE REINFORCEMENT ON TASK COMPLIANCE

Positive and negative reinforcement are effective for treating escape-maintained destructive behavior. The current study evaluated the separate and combined effects of these contingencies to increase task compliance. Results showed that a combination of positive and negative reinforcement was most effective for increasing compliance

THERAPIST- AND SELF-MONITORED DRO CONTINGENCIES AS A TREATMENT FOR THE SELF-INJURIOUS SKIN PICKING OF A YOUNG MAN WITH ASPERGER SYNDROME

The use of differential reinforcement of other behavior (DRO) has decreased, at least partially due to the development of less effortful alternative behavioral interventions (e.g., noncontingent reinforcement; Vollmer, Iwata, Zarcone, Smith, & Mazaleski, 1993). The effort associated with DRO contingencies may be lessened by incorporating self-monitoring components in which clients are responsible for the delivery of reinforcers for their own behavior. The current study evaluates the effectiveness of DRO in the treatment of self-injury when implemented first by the therapist and subsequently by the client