Differential distribution of exchange proteins directly activated by cyclic AMP within the adult rat retina.

The recently discovered exchange protein directly activated by cAMP (Epac), a guanine exchange factor for the G-protein RAP-1, is directly activated by cAMP independently of protein kinase A (PKA). While cAMP is known to be an important second messenger in the retina, the presence of Epac has not been investigated in this tissue. The goal of the present study was to determine if the Epac1 and Epac2 genes are present and to characterize their location within the retina. Western blot analysis revealed that Epac1 and Epac2 proteins are expressed within the retina, and the presence of mRNA was demonstrated with the aid of reverse transcriptase polymerase chain reaction (RT-PCR). Additionally, we used immunofluorescence and confocal microscopy to demonstrate that Epac1 and Epac2 have overlapping as well as unique distributions within the retina. Both are present within horizontal cells, rod and cone bipolar cells, cholinergic amacrine cells, retrograde labeled retinal ganglion cells, and Müller cells. Uniquely, Epac2 was expressed by cone photoreceptor inner and outer segments, cell bodies, and synaptic terminals. In contrast, Epac1 was expressed in vesicular glutamate transporter 1 (VGlut1) and C-terminal binding protein 2 (CtBP2) positive photoreceptor synaptic terminals. Together, these results provide evidence that Epac1 and Epac2 are differentially expressed within the retina and provide the framework for further functional studies of cAMP pathways within the retina.

Effects of rolipram on adult rat oligodendrocytes and functional recovery after contusive cervical spinal cord injury.

Traumatic human spinal cord injury (SCI) causes devastating and long-term hardships. These are due to the irreparable primary mechanical injury and secondary injury cascade. In particular, oligodendrocyte cell death, white matter axon damage, spared axon demyelination, and the ensuing dysfunction in action potential conduction lead to the initial deficits and impair functional recovery. For these reasons, and that oligodendrocyte and axon survival may be related, various neuroprotective strategies after spinal cord injury are being investigated. We previously demonstrated that oligodendrocytes in the adult rat epicenter ventrolateral funiculus (VLF) express 3'-5'-cyclic adenosine monophosphate-dependent phosphodiesterase 4 (PDE4) subtypes and that their death was attenuated up to 3 days after contusive cervical SCI when rolipram, a specific inhibitor of PDE4, was administered. Here, we report that (1) there are more oligodendrocyte somata in the adult rat epicenter VLF, (2) descending and ascending axonal conductivity in the VLF improves, and that (3) there are fewer hindlimb footfall errors during grid-walking at 5 weeks after contusive cervical SCI when rolipram is delivered for 2 weeks. This is the first demonstration of improved descending and ascending long-tract axonal conductivity across a SCI with this pharmacological approach. Since descending long-tract axonal conductivity did not return to normal, further evaluations of the pharmacokinetics and therapeutic window of rolipram as well as optimal combinations are necessary before consideration for neuroprotection in humans with SCI.

The novel distribution of phosphodiesterase-4 subtypes within the rat retina.

Phosphodiesterases (PDEs) are important regulators of signal transduction processes. While much is known about the function of cyclic GMP-specific PDEs in the retina, much less is known about the closely related, cyclic AMP-specific PDEs. The purpose of the present study is to characterize and localize PDE4 within the adult rat retina. We have used Western blotting, RT-PCR, and immunohistochemistry together with retrograde labeling to determine the presence and location of each PDE4 subtype. Western blot analysis revealed that multiple isoforms of PDE4A, B, and D subtypes are present within the retina, whereas the PDE4C subtype was absent. These data were confirmed by RT-PCR. Using immunohistochemistry we show that all three PDE4s are abundantly expressed within the retina where they all colocalize with retrograde-labeled retinal ganglion cells, as well as bipolar cells, horizontal cells, and cholinergic amacrine cells, whereas Müller cells lack PDE4 expression. Uniquely, PDE4B was expressed by the inner and outer segments of rod photoreceptors as well as their terminals within the outer plexiform layer. Collectively, our results demonstrate that PDE4s are abundantly expressed throughout the rodent retina and this study provides the framework for further functional studies.

Exploring multicultural competencies of occupational therapists: implications for education and training.

The purpose of this investigation was to explore the influence of demographic and educational variables on self-reported multicultural competencies of occupational therapists. A sample of 94 occupational therapists currently working in the field participated in this investigation. Multicultural course work, seminars and workshops, percentage of minority patients worked with, and highest degree held were found to correlate significantly with self-reported multicultural competencies. Regression analyses found that highest degree held, percentage of minority patients worked with, multicultural course work, and participation in multicultural seminars and workshops accounted for about half of the variance in multicultural awareness. These findings are discussed in terms of academic courses and continued professional training and education for occupational therapists.

Nurses' attributions about rape victims.

In an evaluation experiment, 80 registered nurses (64% of whom had cared for at least one rape victim) read an account of a rape involving a woman who drove to a drugstore on her way home from work. By random assignment, the nurses read one of four versions of the rape which varied in terms of whether or not the victim locked her car door (carelessness manipulation) and time of attack (5:00 p.m. or midnight). Subjects evaluated the victim on a series of 0 to 9 bipolar adjective scales. MANOVA showed a significant main effect for the locked/unlocked conditions: Nurses who read the unlocked version, as compared to those reading the locked version, showed differences in terms of more negative ratings of the victim on such variables as less liking for her, less identification with her, and assigning greater responsibility for the rape to her (p less than or equal to .005). Time of attack and the interaction were not significant.

Management of gallstones in a district general hospital.

This survey reviews 815 consecutive patients undergoing surgery for benign biliary disease. There were no deaths following elective operations and the overall mortality was 0.7 per cent. One-third of patients had one or more complications. The mortality in patients having common bile duct exploration (n = 160) by one or more methods was 2.5 per cent (4 patients) with 46 per cent of these patients having complications. Of 95 patients undergoing duct exploration and postoperative T-tube cholangiography, 7 had unexpected residual calculi after initial cholecystectomy. Five have had further surgery to clear the duct. All patients having duct surgery alone for retained stones (n = 24) had previously had cholecystectomy with or without supraduodenal duct exploration. Of all patients undergoing choledochoduodenostomy or transduodenal sphincter exploration only one has returned with evidence of retained calculi. Patients with choledocholithiasis were examined in an attempt to identify a high risk group. These were found to be elderly patients, having emergency surgery for sepsis and on whom more than one duct procedure was performed (mortality 10 per cent).