Xenopus sonic hedgehog guides retinal axons along the optic tract.

The role of classic morphogens such as Sonic hedgehog (Shh) as axon guidance cues has been reported in a variety of vertebrate organisms (Charron and Tessier-Lavigne [2005] Development 132:2251-2262). In this work, we provide the first evidence that Xenopus sonic hedgehog (Xshh) signaling is involved in guiding retinal ganglion cell (RGC) axons along the optic tract. Xshh is expressed in the brain during retinal axon extension, adjacent to these axons in the ventral diencephalon. Retinal axons themselves express Patched 1 and Smoothened co-receptors during RGC axon growth. Blocking Shh signaling causes abnormal ventral pathfinding, and targeting errors at the optic tectum. Misexpression of exogenous N-Shh peptide in vivo also causes pathfinding errors. Retinal axons grown in culture respond to N-Shh in a dose-dependent manner, either by decreasing extension at lower concentrations, or retracting axons in the presence of higher doses. These data suggest that Shh signaling is required for normal RGC axon pathfinding and tectal targeting in the developing visual system of Xenopus. We propose that Shh serves as a ventral optic tract repellent that helps to define the caudal boundary for retinal axons in the diencephalon, and that this signaling is also required for initial target recognition at the optic tectum.

"We'll do this together": the role of the first person plural in fostering partnership in patient-physician relationships.

BACKGROUND: Partnership is integral to therapeutic relationships, yet few studies have examined partnership-fostering communication behaviors in the clinic setting. We conducted this study to better understand how statements in which physicians use the first person plural might foster partnership between patient and provider. METHODS: We audio-recorded encounters between 45 HIV providers and 418 patients in the Enhancing Communication and HIV Outcomes (ECHO) Study. We used the Roter Interaction Analysis System (RIAS) to code for statements made by the physician that used the first person plural to refer to themselves and their patient. Using multiple logistic regression, we examined the associations between the occurrence of one or more first person plural statements with patient ratings of provider communication. To better understand the meaning of first person plural statements, we conducted a qualitative analysis. MAIN RESULTS: Providers were mostly white (69%) and Asian (24%); 57% were female. Patients were black (60%), white (25%), and Hispanic (15%); 33% were female. One or more first person plural statements occurred in 92/418 (22%) of encounters. In adjusted analyses, encounters with first person plural statements were associated with younger patient age (OR 0.97, 95% CI 0.94-0.99), higher patient depression scores (highest tertile compared to lowest tertile: OR 1.89, 95% CI 1.01-3.51), the patient not being on anti-retroviral therapy (OR 0.53, 95% CI 0.29-0.93), and older provider age (OR 1.05, 95% CI 1.00-1.09). After adjustment, patients were less likely to highly rate their provider's communication style if first person plural statements were used (AOR 0.57, 95% CI 0.33-0.96). There were 167 first person plural statements made by physicians in the 418 encounters. Qualitative analysis revealed that many first person plural features had at least one negative feature such as being overtly persuasive ("That's going to be our goal"), indirect ("What can we do to improve your diet?"), or ambiguous ("Let's see what we can do"), although there were also positive statements that involved patients in the health-care process, contributed to a mutual understanding, and addressed the patients' goals. CONCLUSIONS: Contrary to our hypotheses, use of first person plural was not associated with higher ratings of provider communication, probably because some of these statements were overtly persuasive, indirect, or ambiguous. Physicians should become aware of benefits and pitfalls of using the first person plural with patients. Further research is needed to determine the most effective methods through which providers can build alliances with patients.