Recent Publications by CFE Educators

In this study in the rat, we evaluated the effect of unilateral, multiple cervical dorsal rhizotomy (C5-T1) on nociceptive thresholds in the unoperated limbs. This was tested by measuring the vocalization threshold to paw pressure. We report that deafferentation by dorsal rhizotomy results in a delayed, but transient increase in mechanical nociceptive thresholds in the 3 innervated limbs.

Lung tissue from patients with interstitial lung disease (ILD), adult respiratory distress syndrome (ARDS), and control subjects with no obvious fibrotic lung disease was analyzed for its content of the collagen cross-links hydroxylysinonorleucine (HLNL), dihydroxylysinonorleucine (DHLNL), and hydroxypyridinium (OHP). We observed significant elevations of the DHLNL:HLNL ratio in patients with ARDS, and significant increases in the content of OHP in lungs of patients with ILD. These results are consistent with data from animal models of fibrotic lung disease, suggesting that increases in the DHLNL:HLNL ratio of lung collagen may serve as a marker of an acute fibrotic episode, whereas increased lung collagen OHP content serves as a marker of chronic lung fibrosis. We suggest that the underlying mechanism for the changes in DHLNL content in (pre)fibrotic acutely injured lung tissue and in OHP content in long-term fibrosis may be an increase in the activity of lysyl hydroxylase, a key intracellular enzyme responsible for a specific post-translational modification of collagen.

Previous experiments have shown that noxious stimulation increases expression of the c-fos proto-oncogene in subpopulations of spinal cord neurons. c-fos expression was assessed by immunostaining for Fos, the nuclear phosphoprotein product of the c-fos gene. In this study, we examined the effect of systemic morphine on Fos-like immunoreactivity (FLI) evoked in the formalin test, a widely used model of persistent pain. Awake rats received a subcutaneous 150 microliters injection of 5% formalin into the plantar aspect of the right hindpaw. The pattern of nuclear FLI was consistent with the known nociceptive primary afferent input from the hindpaw. Dense labeling was recorded in the superficial dorsal horn (laminae I and IIo) and in the neck of the dorsal horn (laminae V and VI), areas that contain large populations of nociceptive neurons. Sparse labeling was noted in lamina IIi and in the nucleus proprius (laminae III and IV), generally considered to be nonnociceptive areas of the cord. Fos immunoreactivity was also evoked in the ventromedial gray, including laminae VII, VIII, and X. There was no labeling in lamina IX of the ventral horn. Since FLI was time dependent and distributed over several spinal segments, we focused our analysis where maximal staining was found (L3-L5) and at the earliest time point of the peak Fos immunoreactivity (2 hr). Twenty minutes prior to the formalin injection, the rats received morphine (1.0, 2.5, 5.0, or 10 mg/kg, s.c.) or saline vehicle. Two hours later, the rats were killed, their spinal cords removed, and 50 microns transverse sections of the lumbar enlargement were immunostained with a rabbit polyclonal antiserum directed against Fos. Prior treatment with morphine sulfate profoundly suppressed formalin-evoked FLI in a dose-dependent and naloxone-reversible manner. The dose-response relationship of morphine-induced suppression of FLI varied in different laminae. To quantify the effect of morphine on FLI, labeled neurons in sections taken from the L4/5 level of each rat were plotted with a camera lucida and counted. Staining in the neck of the dorsal horn (laminae V and VI) and in more ventral laminae VII, VIII, and X, was profoundly suppressed by doses of morphine which also suppress formalin-evoked behavior. Although the labeling was also significantly reduced in laminae I and II, at the highest doses of morphine there was substantial residual labeling in the superficial dorsal horn. These data indicate that analgesia from systemic opiates involves differential regulation of nociceptive processing in subpopulations of spinal nociceptive neurons.

Sympathetic efferents contribute to the severity of joint injury in experimental arthritis in the rat, [Levine J. D. et al. (1986) J. Neurosci. 6, 3423-3429] and beta 2-adrenergic receptor antagonists suppress the disease [Levine J. D. et al. (1988) Proc. natn. Acad. Sci. U.S.A. 85, 4553-4556]. The present study was directed at determining the endogenous ligand for, and target of, the beta 2-receptor contribution to arthritis. We report that adrenal medullectomy significantly reduced joint injury in experimental arthritis, but that severe joint injury was re-established in adrenal medullectomized rats chronically treated with epinephrine or the beta 2-agonist, salbutamol. The ability of these two drugs to enhance joint injury in adrenal medullectomized rats was blocked by sympathectomy. These data suggest that adrenal medulla-derived epinephrine acts at beta 2-adrenoceptors on sympathetic efferent nerve terminals, to contribute to the severity of experimental arthritis.

WGAapoHRP-Au is a colloidal gold conjugate of wheat germ agglutinin (WGA) coupled to enzymatically inactive (apo) horseradish peroxidase (HRP). This protein-gold complex has proven very useful for retrograde tracing studies in the nervous system (Basbaum and Menétrey: J Comp Neurol 261:306, 1987). To identify retrogradely labeled cells, the colloidal gold is made visible by silver intensification. As the tracer has no HRP enzymatic activity, it can be combined with HRP-based procedures (or with fluorescent methods) in a variety of multiple-label studies. Standard silver intensification procedures, however, are run at low pH and therefore are incompatible with good EM preservation; moreover, osmication of the tissue oxidizes the silver product, which is then lost in subsequent dehydration steps. This report describes a rapid and simple commercially available silver intensification procedure. The procedure is run at neutral pH and can be performed after osmication. The tracer is readily detected at the EM level and tissue preservation is excellent. This report also demonstrates how sections containing retrogradely labeled neurons can be stained with a post-embedding immunocytochemical method so that the transmitter content of synaptic inputs to these neurons can be identified.

Fibroblasts in healthy adult lung are quiescent, synthesizing little collagen. We studied lung biopsies from 30 patients with pulmonary fibrosis, using immunohistochemistry with monoclonal antibodies against the propeptides of type I collagen to localize fibroblasts actively synthesizing collagen. Adjacent sections were stained with antibodies to type III and IV collagen, fibrin, cytokeratin, plasma fibronectin, or EDIIIa-containing "cellular" fibronectin (cFN). In rapid pulmonary fibrosis, including the proliferative phase of diffuse alveolar damage, organizing pneumonia, and subacute idiopathic fibrosis, collagen-synthesizing cells were numerous in organizing exudate filling airspaces but were also seen in the interstitium of the alveolar walls, interlobular septa, and walls of blood vessels. The new matrix deposited in the airspaces also contained type III collagen and EDIIIa-containing fibronectin. In chronic pulmonary fibrosis, more than half of the biopsies showed foci of collagen synthesis and cFN deposition near the air-tissue interface. The foci were consistently localized outside remnants of basal lamina and therefore within airspaces. The results indicate that (1) fibrosis in chronic idiopathic pulmonary fibrosis results mainly from organization of exudate within airspaces, just as it does after acute lung injury, and (2) during this process, fibroblasts increase their synthesis of collagen and fibronectin coordinately. Foci of active matrix deposition provide evidence for the progressive nature of chronic pulmonary fibrosis.

Medical school faculty often cite the fear of litigation as a reason for their reluctance to offer candid evaluations of students' and residents' performances and to dismiss them when necessary. This article is written to reassure faculty that they have nothing to fear from the courts and that they should uphold high academic standards. Three legal issues of concern to faculty are addressed: What does fair and equitable treatment entail? What are the due process requirements for academic dismissals? Are negative performance evaluations libelous and defamatory? Recommendations are made to meet legal requirements and to promote academic excellence.

Bombesin-related peptides are growth factors for a variety of cells, including normal human bronchial epithelial cells. An ELISA for bombesin-like peptides (BLP) has been devised using the MAb BBC353, which is specific for the biologically active carboxy-terminal fragment shared by all known BLP. Using this ELISA, we measured bronchoalveolar lavage (BAL) fluid levels of BLP in normal cigarette smokers (n = 15) and normal nonsmokers (n = 18). Smokers' BAL fluid contained increased levels of BLP, whether expressed in terms of BAL fluid volume (P = 0.0001) or protein content (P less than 0.05). BLP levels did not correlate with any cellular constituent in the BAL fluid but immunostaining of lung tissue with BBC353 revealed an intense specific staining of neuroendocrine cells, implying these as a potential source. Two peaks of bombesin-like immunoreactivity were purified using sequential reverse phase and gel filtration HPLC. Both BLP have apparent molecular weights similar to gastrin-releasing peptide on gel filtration HPLC analysis. However, the amino acid composition of these BLP is different from that of gastrin-releasing peptide or neuromedin B, the only known mammalian forms of BLP, suggesting either incomplete purification or novel peptides. Sequence analysis could not be performed due to blocking groups at the amino terminus of these peptides. Our data demonstrate that cigarette smoking is associated with increased levels of pulmonary BLP and imply a potential role for these neuropeptides in the lung's response to tobacco smoke.

This study used immunocytochemistry to examine the pattern of noxious-stimulus evoked expression of the proto-oncogene c-fos in the spinal cord of the rat. Both noxious somatic and joint stimulation in awake rats evoked the expression of c-fos protein in similar areas of the lumbar spinal cord. C-fos-immunoreactive neurons were found in laminae I and outer II, in the lateral part of the neck of the dorsal horn, and in laminae VII, VIII, and X. All of the labelled neurons were located ipsilateral to the injured hindpaw, except for lamina VIII where bilateral labelling was recorded. The c-fos-immunoreactive neurons in lamina I extended from the L3 segment to the rostral sacral cord; staining in outer lamina II was only found at the L4 segment. The more deeply located cells, of the dorsal and medioventral horns, had the most extensive rostrocaudal spread; they were found from L1 through the rostral sacral segments. The pattern of c-fos-immunoreactivity produced by visceral stimulation, in anesthetized rats, differed in several ways from that produced by somatic stimulation. First, there was considerable bilateral, symmetrical labelling of cells. Second, there was a much more extensive rostrocaudal spread of the labelling, from cervical through sacral cord. Third, the greatest rostrocaudal spread was found for neurons in the superficial dorsal horn; labelled cells in the neck of the dorsal horn and in lamina X were restricted to segments at the thoracolumbar junction, which is also where the superficial dorsal horn cells were most concentrated. Fourth, there were very few labelled neurons in the outer part of the substantia gelatinosa. To determine whether any neurons that express the c-fos protein in response to noxious stimulation project to supraspinal sites, we combined the immunocytochemical localization of c-fos with the localization of a retrogradely transported protein-gold complex that was injected into the thalamic and brainstem targets of the major ascending spinal pathways. In rats that received the somatic noxious stimulus, 90% of all of the c-fos projection neurons were recorded in four major areas of the cord: lamina I (37%), the lateral part of the neck of the dorsal horn (24%), laminae VIII (9%), and X (29%). The remainder were scattered throughout the spinal gray. With the exception of lamina VIII, which contained c-fos projection neurons contralateral to the inflamed paw, all of the c-fos projection neurons were located ipsilateral to the injured paw.(ABSTRACT TRUNCATED AT 400 WORDS)