Epithelium-derived inhibitory factor in human bronchus

The potencies of histamine and methacholine were significantly increased by approximately 2- and 5-fold respectively in human non-diseased isolated bronchi on removal of the epithelium. In contrast, no increases in spasmogen potency were observed following epithelium removal in bronchi obtained from a sample of asthmatic human lung. The failure of epithelium removal to increase asthmatic bronchial sensitivity to histamine may have been due to a reduction in the release of an epithelium-derived inhibitory factor (EpDIF) resulting from disease-induced epithelial damage. A co-axial bioassay system in which endothelium-denuded rat aorta was used as the assay tissue was used to detect the release of a vasorelaxant EpDIF from human bronchial tissue. Histamine (100 microM) and methacholine (25 microM), in the presence of indomethacin (5 microM), reduced phenylephrine-induced tone in endothelium-denuded rat aorta in co-axial assemblies by 75 +/- 11 and 67 +/- 9% respectively. Removal of the bronchial epithelium abolished these responses, indicating that they were mediated by an EpDIF. It is possible that human airway smooth muscle is sensitive to this vasorelaxant EpDIF and that the absence of the source of this factor following epithelium removal caused the increases in sensitivity to spasmogens. Alternatively, the human bronchial epithelium may also release an EpDIF selective for airway smooth muscle.     

A VIP antagonist distinguishes VIP receptors on spinal cord cells and lymphocytes

Vasoactive intestinal peptide (VIP) is a neuropeptide which also interacts with cells of the immune system. The paucity of specific VIP receptor antagonists has hampered studies of possible receptor heterogeneity and of VIP function. To aid in achieving these goals, a new VIP antagonist, a hybrid between neurotensin and VIP, has been synthesized. This peptide interacted with VIP receptors on spinal cord cells with an affinity 10-fold greater than VIP itself. In contrast, 1000-fold higher concentrations of the antagonist were required to displace labeled VIP from its receptor on lymphoid cells as compared to VIP itself, suggesting VIP receptor heterogeneity between immune and spinal cord cells.     

Age-dependent Responses to Nerve Injury- induced Mechanical Allodynia

Background: Developmental differences in responses to acute and chronic nerve injury have received minimal attention. This study examines developmental differences in behavioral responses to a proximal (closer to the spinal cord) (L5 and L6 spinal nerve root ligation) or to a more distal (closer to peripheral innervation) (partial sciatic nerve ligation) nerve injury in rats paralleling the infant to young adult human.

Methods: Withdrawal thresholds to von Frey filament testing in the hind paw were determined before and various times after either spinal nerve root ligation or partial sciatic nerve ligation in rats aged 2, 4, and 16 weeks. Control rats of these ages were observed serially without surgery. Times for withdrawal thresholds to mechanical stimuli to return to 80% of that of the hind paw in the control animals were compared among the different ages in the two models.

Results: Baseline withdrawal thresholds in younger rats were lower (P < 0.05). In the 2-week-old animals, distal injury partial sciatic nerve ligation did not cause a reduction in withdrawal threshold from baseline. This was different from the spinal nerve root ligation group and the older animals in the partial sciatic nerve ligation group. However, when compared with age-matched control animals, both nerve injuries resulted in reduced withdrawal thresholds (P < 0.05). The resolution of hypersensitivity to mechanical stimulation, as measured by return of threshold to 80% of controls, occurred more quickly in 2-week-old than in 4- and 16-week-old animals in both injury models (P < 0.05).     

Bilateral malignant glaucoma.

Two cases of bilateral malignant glaucoma are presented. In one case the condition developed sequentially in the two eyes; pars plana vitrectomy was eventually needed in the operated eye, whereas the condition responded to medical treatment in the fellow eye. In the second case the two eyes were involved simultaneously nearly 1 year after surgery, and the glaucoma responded to medical treatment.     

Rate of nitrous oxide exchange across the middle ear mucosa in monkeys before and after blockage of the mastoid antrum.

OBJECTIVES: We tested the hypothesis that mastoid volume buffers the rate of change in middle ear pressure caused by transmucosal, inert gas exchange. STUDY DESIGN: Twelve monkeys were randomly assigned to group 1 or group 2. Right ears of group 1 had sham surgery and of group 2 had obstruction of the mastoid antrum. Before and after surgery, the time constant for transmucosal N(2)O exchange was estimated from N(2)O breathing experiments. The hypothesis predicts that the postoperative time constant measured for right ears of group 2 but not group 1 is greater than that measured before surgery. RESULTS: Mastoid antrum block significantly decreased right middle ear volume but did not affect the time constant for transmucosal N(2)O exchange. CONCLUSION: A mastoid gas-reserve function is not supported by the experimental data. SIGNIFICANCE: These results for monkeys and the theory developed to explain the effect of mastoid volume on transmucosal inert gas exchange suggest that the results for previous experiments in humans interpreted as evidencing a mastoid gas-reserve function are consistent with alternative explanations.     

An unexpected complication following immunoadsorption with a staphylococcal protein a column

Extracorporeal immune adsorption with staphylococcal protein A (SPA) columns can remove immune complexes and immunoglobulins in the treatment of a variety of diseases. We present the case of an elderly man with neuropathy associated with monoclonal gammopathy, treated by 3 on-line SPA procedures. At the completion of these treatments his neuropathy relapsed, progressing to near-total paralysis. Return to a baseline clinical status required several months. The reason for this severe relapse is not clear. Possible explanations include SPA activation of T-lymphocytes, with release of gamma interferon and increased antigen recognition, or removal of an anti-idiotype control mechanism. We advise caution in the application of immunoadsorption to conditions in which it has not yet been evaluated. © 1992 Wiley-Liss, Inc.