Recent Publications by CFE Educators

In order to study the organization of the rostral medulla of the cat and its contribution to pain control mechanisms, we have examined the afferent connections of the midline nucleus raphe magnus (NRM), the laterally located nucleus reticularis magnocellularis (Rmc), and the nucleus reticularis gigantocellularis (Rgc) located dorsal to Rmc. Iontophoretic injections of HRP were made into the three regions; the distribution of retrogradely labeled neurons in brainstem and spinal cord was then mapped. While significant differences characterize the source of afferents to Rgc and NRM/Rmc, there is little to distinguish that between NRM and Rmc. The predominant spinal projection is to Rgc; fewer labeled neurons were recorded after injections into Rmc. In contrast, no significant direct spinal projection to NRM was found. All three regions receive input from widespread areas within the medullary and pontine reticular formation. The most pronounced differences in the distribution of retrogradely labeled neurons were found in the midbrain. The major projection to both NRM and Rmc derives from the periaqueductal gray (PAG) and from the adjacent nucleus cuneiformis. Labeled cells are concentrated in the dorsal and lateral PAG; few are found in the ventrolateral PAG. In contrast, Rgc receives few afferents from the PAG; however, after Rgc injections, many cells were recorded in the deep layers of the contralateral tectum. None of the injection sites produced significant labeling of the catecholamine-rich dorsolateral pontine tegmentum or of the nucleus raphe dorsalis. The demonstration of significant PAG projections to NRM/Rmc provides anatomical evidence for the hypothesis that opiate and stimulation-produced analgesia involves connections from PAG to neurons of NRM and Rmc which, in turn, inhibit spinal nociceptors.

A survey of American chief residents in psychiatric training centres was carried out to assess how these training programmes gathered feedback on teacher effectiveness and programme content. The chief resident in each programme was asked to report how his or her department elicited information from their residents about course and teacher quality. Responses from 184 training centres in the United States were obtained and accounted for 75% of the existing centres. Fifty questionnaires were returned with the survey results and were analysed. The seven factors of clinical teacher effectiveness previously described in the literature were used to evaluate these questionnaires. The majority lacked consistent coverage of the teaching factors with the percentages of questionnaires covering a specific behaviour as follows: teacher organization, 58%; instructor knowledge, 42%; group interactional skills, 42%; instructor enthusiasm, 30%; clinical supervision skills, 25%; display of professional characteristics, 19%; and clinical competence, 17%.

This study examined the spinal cord distribution of the endogenous opioid peptide leucine-enkephalin in the cat using immunohistochemical techniques. The distribution of nerve processes was studied in untreated cats; colchicine was administered to study the distribution and morphology of spinal enkephalin-containing perikarya. Enkephalin immunoreactive processes were greatest in laminae I and II (marginal layer and substantia gelatinosa) of the superficial dorsal horn. In many sections, the outer substantia gelatinosa (SG), lamina IIa, was discernibly less immunoreactive than I or IIb. Laminae III and IV were relatively devoid of staining. Laminae V and VII had moderate enkephalin-immunoreactivity, lamina VI somewhat less. Enkephalin immunoreactivity in lamina X, around the central canal, was very dense. Enkephalin-containing beaded varicosities coursed throughout the ventral horn. Although previous studies in the rat emphasized the enkephalin-somata of the SG, we found that in the cat the majority of superficial dorsal horn enkephalin-somata are in the marginal layer. These enkephalin-containing marginal cells were morphologically similar to a population of marginal neurons which project to the brainstem and/or the thalamus. Some light staining small SG neurons were also identified; many were located at the lamina I-II border. Considerably more cells were found ventral to the SG, in lamina III, and at the IV-V border. These latter cells had dendrites coursing dorsally, toward the SG. Numerous immunoreactive cells were found in lamina VIII, in a band across the intermediate gray. These cells fused medially with cells of lamina X. Enkephalin cells were also found in the sacral autonomic nucleus and encircling the central cervical nucleus, Clarke's column, and stilling's nucleus. Although surrounded by labeled cells, the latter regions were devoid of enkephalin-immunoreactive processes. Many of these spinal enkephalin neurons are morphologically similar to and distributed in regions known to contain projection neurons. Thus it is suggested that many spinal enkephalin neurons, generally thought to be local circuit neurons, project rostrally, to other spinal levels and perhaps to brainstem and/or thalamus.

Medical student ratings of clinical teaching in an obstetrics and gynecology clerkship are examined. Analyses were made on 1,567 ratings of 230 faculty members and residents by 320 students. Results revealed high interrater reliability. Overall teaching effectiveness correlated strongly with enthusiasm and active involvement of students. Four underlying factors of clinical teaching were identified through factor analysis. The utility of these data is discussed in relation to faculty development, administrative decision-making, and academic promotions.

1. The nucleus raphe dorsalis (RD) and paragiganto-cellularis (PGL) of the cat contain both 5-HT and leucine-enkephalin (ENK) immunoreactive perikarya. 2. Using a sequential immunoperoxidase-immunofluorescence technique for the localization of ENK and 5-HT, respectively, it was demonstrated that some PGL and RD neurons contain both the indoleamine and the peptide. 3. The double labeled neurons in the DR were characteristically small, round cells predominantly located on the midline of the nucleus, dorsal to the medial longitudinal fasciculus. Numerous large 5-HT containing perikarya were also found in the DR, but these cells did not contain ENK immunoreactivity.

The serotonin-containing nucleus raphe dorsalis (RD) of the cat contains numerous leucine-enkephalin immunoreactive cells, throughout its rostral-caudal extent. The distribution of the enkephalin neurons closely parallels the cytoarchitectural boundaries of the RD, as described in previous Nissl preparations. Enkephalin perikarya are most numerous along the midline of the RD, but also extend ventrally, into the dorsal portion of the nucleus centralis superior, and laterally, into the 'wings' of the rostral RD, at the level of the IV nucleus. The possible contribution of these enkephalin cells to endogenous pain control systems is discussed.