Recent Publications by CFE Educators

In this study we examined the distribution of two different endogenous opioid peptides in the nucleus of the solitary tract of the rat medulla. As a marker for immunoreactive enkephalin, we used an antiserum directed against one of the proenkephalin products, methionine enkephalin-arg-gly-leu (m-Enk). To identify immunoreactive dynorphin we used an antiserum directed against the prodynorphin product, dynorphin B (Dyn B). The PAP method was used on both colchicine and normal animals. Caudal to the obex, within the commissural nucleus, there is extensive overlap of both immunoreactive m-Enk and Dyn B terminals and cells. While the cells are morphologically similar, the immunoreactive dynorphin cells are somewhat larger. Rostral to the obex, there is a marked difference in the distribution of the two compounds. Immunoreactive m-Enk terminals are concentrated medial to the solitary tract; there is minimal staining laterally. In contrast, immunoreactive Dyn B terminals are concentrated lateral to the solitary tract. The rostral cellular distribution of the two opioid peptides follows a similar pattern. The morphology of the medially located m-Enk and laterally located Dyn B cells is also readily distinguished. The former are small, round cells with minimal dendritic labelling; the latter are larger, pyramidal neurons with prominent apical and basal dendrites. Since the medial and lateral nuclei of the solitary tract have been associated with cardiovascular and respiratory control, respectively, these data suggest that different endorphin families have different functional actions within the nucleus of the solitary tract.

Influenza A virus has been demonstrated to enhance superoxide generation and chemoluminescence (CL) in human polymorphonuclear leucoytes (PMNs) under in vitro conditions. Although the mechanisms of virus-enhanced neutrophil activity is not established, calmodulin concentrations are known to increase in some virus-transformed cells. In the following experiments, we evaluated the PMN response to the calmodulin-inhibitor trifluoperazine (TFP) after an incubation with influenza A virus. Human PMNs were isolated from whole blood and were incubated with either influenza A virus (at 50% egg-infective dose per 1 leukocyte) or noninfected allantoic fluid. After incubation with influenza virus, the CL response of isolated PMNs to opsonized zymosan particles was measured. The influenza virus-treated PMNs had a mean (+/- SEM, n = 16) increase in light emission of 59.5 +/- 7.7%. TFP, in concentrations of 6 micron, 8 micron, and 10 microM, inhibition of CL was similar in influenza virus and allantoic fluid-treated neutrophils. These data suggest that, although the influenza A virus enhanced the PMN "respiratory burst" to opsonized zymosan particles, it did not alter the cell response to one calmodulin inhibitor, TFP.

There is evidence that substance P is a peptide neurotransmitter of some unmyelinated primary afferent nociceptors and that its release from the peripheral terminals of primary afferent fibers mediates neurogenic inflammation. The investigators examined whether substance P also contributes to the severity of adjuvant-induced arthritis, an inflammatory disease in rats. They found that, in the rat, joints that developed more severe arthritis (ankles) were more densely innervated by substance P-containing primary afferent neurons than were joints that developed less severe arthritis (knees). Infusion of substance P into the knee increased the severity of arthritis; injection of a substance P receptor antagonist did not. These results suggest a significant physiological difference between joints that develop mild and severe arthritis and indicate that release of intraneuronal substance P in joints contributes to the severity of the arthritis.

This study addressed the possible coexistence of products of the proenkephalin and prodynorphin opioid peptide precursors in single neurons of the central nervous system of the rat. Antisera directed against met-enkephalin-arg-gly-leu and against Dyn B were used in immunohistochemical preparations of sections through the rat medulla. Examination of serial three micron frozen sections stained alternately with the two different antisera revealed that the majority of labelled neurons stain with only one of the two antisera. In specific area, however, immunoreactive m-enk and Dyn B could be detected in the same neuron. This was particularly true of the caudal ventrolateral nucleus of the solitary tract, where the two peptides were colocalized in most neurons. Other areas where the two peptides coexist include the midline raphe and the nucleus reticularis paragigantocellularis. These data provide the first evidence for colocalization of different opioid peptide families in single CNS neurons.

Using personality style preferences as the basis for faculty development workshops, physician educators in several departments of obstetrics and gynecology learned how to use these differences to enhance clinical teaching. Data from five workshops are analyzed to determine the predominant personality styles of 184 department chairmen, faculty, and residents in obstetrics and gynecology. Chairmen had a stronger preference for taking charge than faculty or residents. As a whole, all preferred use of logic and action in pursuit of excellence. These findings are discussed in relation to student ratings of faculty clinical teaching and to faculty development.

Affinity-purified goat anti-rabbit immunoglobulin G (GAR) was conjugated with (3H)-propionyl succinimidate and used to localize substance P (SP), enkephalin (ENK), and serotonin immunoreactive sites in the spinal dorsal horn and medulla of the rat and cat. Autoradiographic localization was demonstrated on paraffin, frozen, Vibratome, and 2 micron plastic sections. The latter were obtained from radiolabeled Vibratome sections that were embedded in epoxy resin. The distribution of SP, ENK, and serotonin demonstrated by radioimmunocytochemistry was comparable to that observed on semiadjacent sections using peroxidase-antiperoxidase (PAP) immunocytochemistry. The autoradiograms, however, were generated using primary antibody concentrations up to five times more dilute than concentrations used for the PAP procedure. Indirect radioimmunocytochemistry using a (3H) anti-immunoglobulin G second antibody can be used to localize a variety of monoclonal and polyclonal antisera. It is quantifiable at the light microscopic level and can be potentially used with peroxidase histochemistry to double label immunoreactive structures at the ultrastructural level.

Doctors are encouraged to look upon each patient as a learning experience ( Wyngaarden , 1979). Case-oriented learning begins in the clinical years of medical school and continues throughout the professional career of the doctor. Clinical cases, or anecdotes, have the potential of producing accurate, relevant and meaningful learning for the clinician even though they are uncontrolled in a scientific sense. However, unusual or atypical cases can also result in erroneous learning which can negatively affect patient care. The purpose of this article is to identify difficulties in this form of subjective learning which can lead to suboptimal doctor practice patterns. Six actual clinical cases are briefly described to illustrate how inaccurate learning distorted subsequent clinical problem-solving by doctors. Suggestions are then made for ameliorating this difficulty.

Through combined ultrastructural localization of ENK immunoreactivity and [3H]5-HT uptake sites, it was found that 5-HT radiolabeled axons contact ENK immunoreactive cell bodies and small dendrites in the cat superficial dorsal horn. While some contacts displayed both pre- and postsynaptic specializations, the majority lacked a definitive synaptic cleft and postsynaptic density. These results suggest that 5-HT-containing axons, presumably derived from the medullary nucleus raphe magnus, directly influence spinal opiod antinociceptive activity.