Delayed leucocytic emigration after intra-dermal injections and thermal injury

ACUTE INFLAMMATION IN THE RENAL CORTEX AND MEDULLA FOLLOWING THERMAL INJURY

As determined by serial histologic study, the leukocyte component of the acute inflammatory response to thermal injury in the medulla of the kidney of rabbits was markedly delayed and diminished in intensity when compared with the response of the cortex. Similar differences in granulocyte mobilization between cortex and medulla were seen following the inoculation of bacteria. Hydronephrosis produced by ureteral ligation had no discernible effect upon the inflammatory response in either cortex or medulla following thermal burns. The susceptibility of the cortex to E. coli infection was markedly enhanced during leukopenia induced by nitrogen-mustard. These results suggest that deficiencies in granulocyte mobilization play an important role in the increased susceptibility of the renal medulla to bacterial infection.

PATHOGENESIS OF INFLAMMATION. II. IN VIVO OBSERVATIONS OF THE INFLAMMATORY EFFECTS OF ACTIVATED HAGEMAN FACTOR AND BRADYKININ

Activated Hageman factor, when injected into the rabbit ear chamber, produces a delayed and prolonged inflammatory response characterized by prominent sticking and emigration of leucocytes. In contrast, preformed bradykinin evokes an immediate and more transient response in which leucocytic emigration occurs less frequently. It is concluded that either Hageman factor produces its inflammatory effects by mechanisms other than kinin release, or bradykinin released endogenously has effects quite different from those resulting from a single injection of the exogenous material.

Neural regulation of neutrophil involvement in pulmonary inflammation

1. The high viscoelastic property of neutrophils is the major factor contributing to their extensive accumulation (more than 50% of circulating neutrophils) in the pulmonary microvasculature. 2. The cholinergic parasympathetic and adrenergic sympathetic nerves modulate the size of the pulmonary neutrophil pool by regulating arterial and venous pressures, increases in which promote or reduce neutrophil transit times, respectively. 3. Biochemical factors, such as the cytokines and complement, which act upon the neutrophils to increase their viscoelasticity and promote the interaction of neutrophil cell adhesion molecules with counter ligands on the endothelial cell, are the primary factors regulating the size of the pulmonary pool of vascular neutrophils. 4. The primary afferent nerves, through their release of substance P, are the most important neural elements regulating neutrophil accumulation and function. Substance P facilitates the actions of other inflammatory agents (e.g. LTB4, platelet activating factor) on neutrophil adhesion, migration and biochemical reactivity. 5. The sympathetic nervous system indirectly regulates neutrophil functions by regulating the release of an immunosuppressive factor from submandibular glands. 6. With continued, study of nervous system regulation of neutrophil function, the mechanisms by which psychological factors affect these cells will eventually be revealed.

Neurogenic inflammation in the rat trachea. I. Changes in venules, leucocytes and epithelial cells

This study was done to characterize the morphological changes in the respiratory mucosa that occur in neurogenic inflammation, which is a type of inflammation mediated by substances released from sensory nerves. Neurogenic inflammation was produced in the trachea and bronchi of atropine-treated Long-Evans rats by electrically stimulating the left or right superior laryngeal and vagus nerves. This procedure is known to increase vascular permeability in the airways, presumably as a consequence of antidromic activation of sensory vagal axons (Lundberg & Saria, 1982). By using a particulate tracer (Monastral blue, 30 mg kg-1 i.v.) that does not cross the walls of normal tracheal blood vessels but does cross the endothelium of abnormally permeable vessels, it was possible to identify which blood vessels were affected in neurogenic inflammation. Light and electron microscopic examination of tracheas prepared after 2 or 5 min of vagal stimulation revealed that postcapillary venules and collecting venules 7-80 micron in diameter were labelled by extravasated Monastral blue but capillaries, arterioles, and larger venules were not. Venules from which the extravasation occurred had gaps as wide as 1.5 micron between endothelial cells. Most of the abnormally permeable venules were located just beneath the airway epithelium in regions between the cartilaginous rings. Extravasation also occurred from venules in the mucosa overlying the posterior membrane of the extrathoracic trachea, but little occurred in the posterior membrane of the intrathoracic trachea. After unilateral vagal stimulation, vascular permeability was increased on both sides of the trachea; it was also increased in first through fourth order bronchi but only on the side of stimulation. Leucocytes (principally monocytes and neutrophils) were adherent to the endothelium of some of the abnormally permeable venules. Erythrocytes and platelets also were adherent to the walls of some venules. These changes in venules were accompanied by a degranulation of epithelial secretory cells, widening of the spaces between tracheal epithelial cells, and probably an increase in epithelial permeability. Neurogenic inflammation in the trachea and bronchi of rats is thus characterized by increased permeability of postcapillary venules and collecting venules in specific regions of the respiratory mucosa as well as adherence of leucocytes, erythrocytes and platelets to the endothelium of these venules and prominent changes in the respiratory epithelium.

The effect of nerve lesions on the inflammatory response to injury

The effects of surgical denervation, capsaicin, and 6-Hydroxydopamine pretreatment on the inflammatory response to thermal injury have been investigated in the rat. Surgical denervation and capsaicin pretreatment reduced the cellular and exudative reactions to the injury. 6-Hydroxydopamine appeared to have a selective effect on the exudative reaction only. The effects of surgical denervation are partly explained by local and systemic effects of the procedure.

Spontaneous abortions and terminations of pregnancy: histological differences

Curettings from eight gravid uteri are compared with material curetted from 2081 uteri after spontaneous abortions. The outstanding feature of the spontaneous material is the decidual polymorph infiltrate. This was absent in seven of the termination specimens. The one case exhibiting a polymorph infiltrate showed other features of degeneration which suggested that a spontaneous abortion may have been developing before termination occurred. This difference between terminated and spontaneously aborted material may provide a basis for elucidating mechanisms in the latter.

Studies on the permeability of the blood-retinal barrier. II. Breakdown of the blood-retinal barrier by injury

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