Evidence for the influence of testosterone in the performance of spatial navigation in a virtual water maze in women but not in men.

Testosterone (T) may be associated with enhanced spatial navigation in a number of rodent species, although the nature of the relation is equivocal. Similarly, numerous studies in humans generally have found that T is associated with enhanced spatial ability on a variety of paper and pencil tasks that may relate to navigational ability. However, relatively few studies have reported effects of T on navigational ability in humans. We investigated the relationship between endogenous T and performance on a virtual water maze (vWM) and mental rotations test (MROT). ELISA for T was performed on salivary samples that were obtained from participants before and after completion of both spatial tasks. Results indicated that women with low T required more time to locate the hidden platform in the vWM than either group of men or women with high T. Significant negative correlations were found for the entire sample between vWM performance and T, and between vWM latency to escape and MROT. Similar significant correlations were found in women but not men. Thus, our data support the position that T improves performance in the vWM in a linear fashion, most strongly in women. However, further work is needed to confirm this hypothesis in humans.

Radiography and US of os peroneum fractures and associated peroneal tendon injuries: initial experience.

PURPOSE: To retrospectively evaluate the imaging features of os peroneum fractures and associated peroneus longus tendon injuries at radiography and ultrasonography (US) and to retrospectively compare these imaging features with those of multipartite os peroneum. MATERIALS AND METHODS: Institutional review board approval was obtained and informed consent was waived for this HIPAA-compliant study. Retrospective review of findings in nine patients (five men, four women; age range, 35-59 years) with os peroneum fracture at radiography and lateral foot pain after injury who had undergone US of the foot was performed. Three patients underwent magnetic resonance (MR) imaging, and two underwent surgery. Os peroneum fragment separation and displacement relative to the calcaneocuboid joint were measured on radiographs. Os peroneum fracture and peroneus longus tendon injuries were characterized with US and MR imaging. Review of 43 foot radiographs obtained in 36 control subjects (eight men, 28 women; age range, 18-84 years) who were found to have an os peroneum at radiography but were asymptomatic in that area was completed to measure os peroneum distance from the calcaneocuboid joint and bipartite os peroneum fragment distraction. RESULTS: Os peroneum fragment separation of 6 mm or more or displacement of the proximal fragment by 10 mm or more on a lateral radiograph or 20 mm or more on an oblique radiograph was associated with full-thickness peroneus longus tendon tear in seven of seven patients (100%). Os peroneum fragment separation of 2 mm or less or proximal displacement of 8 mm or less was associated with normal tendons, partial-thickness tears, or tendinosis. In the control subjects, os peroneum location ranged from 7 mm proximal to 8 mm distal to the calcaneocuboid joint on lateral radiographs and from 9 mm proximal to 8 mm distal to the joint on oblique radiographs. Bipartite os peroneum fragment separation was 2 mm or less. CONCLUSION: Os peroneum fragment separation of 6 mm or more suggests os peroneum fracture and associated full-thickness peroneus longus tendon tear. Separation of 2 mm or less may be seen with nondisplaced os peroneum fractures and bipartite os peroneum.

Personal information in searching for faces.

Participants searched for a target on a television monitor either after they viewed pictures and received physical information about the target or received that information augmented by personal information. Based on a levels of processing perspective we predicted that the addition of personal information would stimulate deeper processing and result in better identification performance. Personal information did increase identification accuracy, as anticipated. Personal information also increased the duration of time spent on the search task relative to a distractor task, suggesting that personal information may have done more than deepen the processing at the time of encoding. In the current climate of terrorism, this increase in identification performance via a surveillance camera has clear applied significance.

Evidence for time-place learning in the Morris water maze without food restriction but with increased response cost.

Time-place learning is the ability to distinguish between resources that vary in location at different times of day. Only one previous report has demonstrated successful time-place learning without using food as reward. In this experiment, satiated rats failed to form time-place discriminations in a Morris water maze while food deprived rats did, leading to the conclusion that food system activation is necessary for time-place learning. However, in addition to food system activation, response cost was also increased, which previously has been demonstrated to be effective in allowing the formation of time-place discriminations. The purpose of these two experiments is to test whether food system activation or heightened response cost allowed for time-place learning in the Morris water maze. In the first experiment, we replicate the failure to find time-place discriminations in the Morris water maze without food restriction and without increased response cost. In the second experiment, we found that increased response cost without food restriction was effective in allowing the formation of a time-place discrimination. The implications of this result are discussed in light of the timing mechanism used for time-place discriminations, the nature of the response cost, and the event-time-place tripartite association.

Longitudinal stress fracture: patterns of edema and the importance of the nutrient foramen.

DESIGN AND PATIENTS: We reviewed the MR appearances of six cases of longitudinal stress fracture of the lower extremity. RESULTS: One fracture was in the femur and five were in the tibia. Four of the tibial fractures showed edema starting in the mid-tibia at the level of the nutrient foramen with the fracture on the anteromedial cortex. The other tibial fracture started at the nutrient foramen. Three fractures (two tibial and the femur fracture) showed eccentric marrow edema; all fractures showed either eccentric periosteal reaction or soft tissue edema. CONCLUSION: Primary diagnosis of longitudinal stress fracture is made by finding a vertical cleft on one or more axial images. Secondary signs of position of the nutrient foramen and patterns of edema may be useful.

Conditioned inhibitory effects of discriminated Pavlovian training with food in rats depend on interactions of search modes, related repertoires, and response measures.

Like other accounts of conditioned inhibition, behavior systems predicts (and Experiment 1 shows) that during summation and retardation tests, presentation of a negative conditioned stimulus (a CS-) created by discriminative Pavlovian food conditioning will interfere with a focal search response, such as nosing in the feeder. Unlike most other views, behavior systems predicts (and Experiment 2 shows) that the same CS- can potentiate a general search response, like attending to a moving artificial prey stimulus. Contacting the prey stimulus in extinction increased over baseline when a CS- but not a CS Novel preceded it. Experiment 3 showed this effect was not due to unconditioned qualities of the CS-. It appears that the effects of a discriminative CS- depend on the interaction of the training contingency with search modes related to the unconditioned stimulus (US), their perceptual-motor repertoires and environmental support, and the choice of response measure.

Mycobacterium marinum tenosynovitis in a patient on etanercept therapy for rheumatoid arthritis.

Opportunistic infections are a theoretical concern with the use of tumor necrosis factor antagonists, as these agents can impair host immunity. A 61-year-old man with rheumatoid arthritis being treated with only etanercept (soluble tumor necrosis factor receptor) and in remission from the rheumatoid arthritis presented with dorsal tenosynovitis of his right wrist. The synovitis was not improved by a local corticosteroid injection. Surgical exploration showed granulomatous inflammation, and cultures were positive for Mycobacterium marinum infection. Etanercept was discontinued 4 months after the hand infection started. The infection resolved completely with surgery and antibiotic therapy with clarithromycin 500 mg twice daily orally for 3 months. Although M. marinum infection was locally invasive, there was no systemic dissemination of the infection despite ongoing etanercept therapy for 4 months before it was discontinued. With more frequent use of this class of agents for rheumatoid arthritis and Crohn's disease, we caution physicians to be alert for the possibility of this kind of local opportunistic infection.

Autoimmune disease complicating antiviral therapy for hepatitis C virus infection.

OBJECTIVE: To review autoimmune disease complicating therapy with type I interferons (IFNs), specifically in the setting of hepatitis C virus (HCV) infection. METHODS: This study describes 13 reported cases of drug-induced systemic lupus erythematosus (SLE) associated with IFN therapy for the period reported during 1990-2002 by searching MEDLINE. In addition, 2 additional patients are presented, 1 with SLE and 1 with an antineutrophil cytoplasmic antibody (ANCA)-positive nephritis, with long-term follow-up. RESULTS: Of 13 cases of SLE-like syndromes caused by IFN, 2 occurred in patients being treated for HCV infection. Two occurred in patients with rheumatoid arthritis (RA); 1 had Sjogren's syndrome (SS), and 1 laryngeal papillomatosis. The rest were receiving IFN for hematologic malignancies. Symptoms developed between 2 weeks and 7 years after initiation of therapy. Most developed fever and arthralgias/arthritis. Other findings included serositis manifested by tachycardia, dyspnea and pleural effusions, headaches, and hair loss. All had a positive antinuclear antibody (ANA), and the majority had double stranded (ds) DNA antibodies. Two additional patients with chronic HCV infection developed autoimmune disease after combination treatment with IFN-alpha and ribavirin. In each patient, autoimmune disease manifested as severe joint pains, myalgias, fever, rash, and proteinuria. Skin and renal biopsy specimens showed vasculitis and crescentic glomerulonephritis (GN) in the first case, and typical histologic findings of lupus nephritis in the second; clinical and laboratory features were consistent with Wegener's granulomatosis and SLE, respectively. Although both patients had mixed polyclonal cryoglobulins, they were HCV RNA and HCVAb negative. Both received corticosteroids, with gradual clinical and biochemical improvement and without recurrence of viremia. CONCLUSIONS: Autoimmune disorders occur in 4% to 19% of patients receiving IFN-alpha, though SLE-like syndromes are only seen in 0.15% to 0.7%. Clinical and laboratory features of SLE in this setting resemble idiopathic disease, with a generally good outcome after discontinuance of the drug. RELEVANCE: Type I IFNs may cause autoimmune disease such as SLE. As the armamentarium of drugs expands to include other biologics, such as the tumor necrosis factor (TNF)-alpha-inhibiting drugs, the development of autoimmune diseases induced by these drugs is an important consideration for diagnosis and appropriate treatment. Semin Arthritis Rheum 32:163-173.