Potential for Anthropogenic Fin Damage to Affect Individual Responses to Prey in Bluegill Sunfish (Lepomis macrochirus): A New Hypothesis for Kinematic Studies.

In fishes, damage to important morphological structures such as fins through natural damage and anthropogenic factors can have cascading effects on prey capture performance and individual fitness. Bluegill sunfish (Lepomis macrochirus) are a common freshwater species in North America, are a model organism for performance studies, and often experience natural injuries. We opportunistically sampled two populations of fish in the lab to generate a hypothesis for the effect of sub-lethal fin damage resulting from the capture technique on kinematic performance during prey capture in bluegill. We found no statistical differences in mean prey capture kinematics or predator accuracy, but damaged fish used more variable kinematics and more readily struck at non-prey items. We suggest that a reduction in stability and individual consistency occurs as a result of fin damage. This difference could have consequences for higher-order ecological interactions such as competitive ability, despite a lack of apparent performance cost at the individual level, and deserves consideration in future studies of prey capture performance in fish.

Enhanced pain and autonomic responses to ambiguous visual stimuli in chronic Complex Regional Pain Syndrome (CRPS) type I.

Cortical reorganisation of sensory, motor and autonomic systems can lead to dysfunctional central integrative control. This may contribute to signs and symptoms of Complex Regional Pain Syndrome (CRPS), including pain. It has been hypothesised that central neuroplastic changes may cause afferent sensory feedback conflicts and produce pain. We investigated autonomic responses produced by ambiguous visual stimuli (AVS) in CRPS, and their relationship to pain. Thirty CRPS patients with upper limb involvement and 30 age and sex matched healthy controls had sympathetic autonomic function assessed using laser Doppler flowmetry of the finger pulp at baseline and while viewing a control figure or AVS. Compared to controls, there were diminished vasoconstrictor responses and a significant difference in the ratio of response between affected and unaffected limbs (symmetry ratio) to a deep breath and viewing AVS. While viewing visual stimuli, 33.5% of patients had asymmetric vasomotor responses and all healthy controls had a homologous symmetric pattern of response. Nineteen (61%) CRPS patients had enhanced pain within seconds of viewing the AVS. All the asymmetric vasomotor responses were in this group, and were not predictable from baseline autonomic function. Ten patients had accompanying dystonic reactions in their affected limb: 50% were in the asymmetric sub-group. In conclusion, there is a group of CRPS patients that demonstrate abnormal pain networks interacting with central somatomotor and autonomic integrational pathways.

Predictive value of gadolinium enhancement in differentiating ALT/WD liposarcomas from benign fatty tumors.

OBJECTIVE: To determine the predictive value of gadolinium enhancement on MRI in differentiating atypical lipomatous tumor (ALT)/well-differentiated (WD) liposarcoma from benign fatty tumors. DESIGN: All histologically proven fatty tumors with preoperative gadolinium-enhanced MRI were reviewed. Only those tumors with predominantly fatty signal were included. Sensitivity, specificity, and positive and negative predictive values for both gadolinium enhancement and biopsy as predictors for the final diagnosis of ALT/WD liposarcoma were calculated. PATIENTS: From 129 patients evaluated for fatty tumors between 1994 and 2002, the patient population was narrowed to 32 excised fatty tumors with preoperative gadolinium-enhanced MRI. RESULTS: As a predictor of ALT/WD liposarcoma, the presence of gadolinium enhancement showed 100% sensitivity, 71% specificity, 53% positive predictive value and 100% negative predictive value. Needle or incisional biopsy yielded 57% sensitivity, 100% specificity, 100% positive predictive value and 63% negative predictive value for a diagnosis of ALT/WD liposarcoma. CONCLUSIONS: Gadolinium enhancement of a homogeneous fatty soft tissue tumor is a sensitive screening tool to determine possible diagnosis of ALT/WD liposarcoma. Biopsy, on the other hand, is specific but insensitive.

An inexpensive photographic strip-chart recorder for use with a commercially available ultrasonic scanner.

A simple arrangement for producing strip-chart records using moving 70mm film and a commercially available motor-driven film magazine is described. The quality of the records is excellent and the cost is about $500. It is necessary to modify the ultrasonic B-mode scanner slightly by connecting the verticle deflection plates of the oscilloscope to one another through an on-off switch.