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The N-formylmethionyl-leucyl-phenylalanine (f-MLP)-induced metabolic burst activity of peripheral blood neutrophils isolated from acne patients undergoing treatment with 13-cis-retinoic acid at a dose of 1.2 mg/kg/day was investigated using a luminol-enhanced chemiluminescence assay. The mean and median chemiluminescence response were significantly greater (P0.05) in patients receiving 12-cis-retinoic acid than in untreated acne patients or age-matched controls. Pre-incubation of neutrophils with 13-cis-retinoic acid (10 nmol/1) did not affect the chemiluminescence response to formyl peptide. A sequential study over 20 weeks in seven patients demonstrated that chemiluminescence peaked after 2-8 weeks of treatment. In three patients this was accompanied by a worsening of their acne. These studies suggest that, in the initial phase, treatment with 13-cis-retinoic acid may exacerbate, through pro-inflammatory priming of neutrophils, certain neutrophil-mediated inflammatory processes in acne. [ABSTRACT FROM AUTHOR]

Presents an abstract of the article “The Effect of Treatment With 13-cis Retinoic Acid on the Metabolic Burst of Peripheral Blood Neutrophils From Patients With Acne,” by W. Perkins, K. V. Crocket, M. B. Hodgins, R. M. MacKie and J. M. Lackie presented at the Annual Meeting of the British Society for Investigative Dermatology in Birmingham, England.

The N-formylmethionyl-leucyl-phenylalanine (f-MLP)-induced metabolic burst activity of peripheral blood neutrophils isolated from acne patients undergoing treatment with 13-cis-retinoic acid at a dose of 1.0 mg/kg/day was investigated using a luminol-enhanced chemiluminescence assay. The mean and median chemiluminescence response were significantly greater (P less than 0.05) in patients receiving 13-cis-retinoic acid than in untreated acne patients or age-matched controls. Pre-incubation of neutrophils with 13-cis-retinoic acid (10 nmol/l) did not affect the chemiluminescence response to formyl peptide. A sequential study over 20 weeks in seven patients demonstrated that chemiluminescence peaked after 2-8 weeks of treatment. In three patients this was accompanied by a worsening of their acne. These studies suggest that, in the initial phase, treatment with 13-cis-retinoic acid may exacerbate, through pro-inflammatory priming of neutrophils, certain neutrophil-mediated inflammatory processes in acne.

An image analysis package based on a BBC microcomputer has been developed, which can simultaneously track many moving cells in vitro. Cells (rabbit neutrophil leucocytes, BHK C13 fibroblasts, or PC12 phaeochromocytoma cells) are viewed under phase optics with a monochrome TV camera, and the signal digitized. Successive frames are acquired by the computer as a 640 X 256 pixel array. Under controlled lighting conditions, cells can readily be isolated from the background by binary filtering. In real-time tracking, the positions of a given cell in successive frames are obtained by searching the area around the cell's centroid in the previous frame. A simple box-search algorithm is described, which proves highly successful at low cell densities. The resilience of different search algorithms to various exceptional conditions (such as collisions) is discussed. The success of this system in real-time tracking is largely dependent upon the leisurely speed of movement of cells, and on obtaining a clean, high quality optical image to analyse. The limitations of this technique for different cell types, and the possible configurations of more sophisticated hardware, are outlined. This system provides a versatile and automated solution to the problem of studying the movement of tissue cells.

The movement of rabbit and human polymorphonuclear leucocyte neutrophils, both over a 2-D substratum and through a 3-D deformable matrix, has been analysed by time-lapse filming and visual migration assays, and the effect of the drug pentoxifylline on their movement has been investigated. This drug may affect cell deformability. At low doses of pentoxifylline, the speed of movement of the neutrophil leucocytes is enhanced, both in 3-D matrices and on a 2-D substratum. In addition, adhesion assays were performed on neutrophils from both species; the drug does not affect adhesion, ruling out an enhancement of movement through adhesion modulation. The implications of these findings for the penetration of connective tissues are discussed.

This study examines and compares the prophylactic role of aprotinin and Dextran 40 in acute pancreatitis. Experimental acute pancreatitis was induced in 70 male Wistar rats using the closed-duodenal-loop technique. The rats were randomly divided into four groups; sham operation, untreated acute pancreatitis, and therapy with aprotinin or Dextran 40. Samples of blood and urine were collected at the beginning and at the end of the 24-hr period for measurement of amylase and creatinine which allowed calculation of the amylase-creatinine clearance ratio (ACCR). Mortality in the aprotinin group was the same as the untreated rats (20%). Dextran 40 therapy was associated with a lower mortality rate (6.7%). Light microscopic examination confirmed that the histologic changes of acute pancreatitis were less severe in both the aprotinin- and Dextran 40-treated rats. The ACCR was elevated after Dextran 40 therapy, which was due mainly to high urinary amylase levels. These results suggest that Dextran 40 may have a prophylactic role in acute experimental pancreatitis but again emphasizes the high false-positive rate of the ACCR determination.

Prostaglandin E1 (PGE1) was tested for cytoprotective activity against the development of experimental acute pancreatitis in the rat induced by the closed duodenal loop technique. Sham-operated, untreated and PGE1-treated pancreatic rats were investigated. All rats received an initial bolus of 3 ml 5% dextrose in normal saline (D5NS) via jugular catheter 30 min prior to surgery, and a continuous subcutaneous infusion of 35 ml D5NS over 24 h. Each treated rat received 10 micrograms/kg PGE1 in the initial bolus and a maintenance dosage of 10 micrograms/kg/h via the infusate. Serum amylase rose significantly in all pancreatic rats with no significant difference between treated and untreated. Pancreatic edema was more pronounced in PGE1-treated than in untreated rats. The ischemic and autolytic damage to acinar cells and vascular endothelial cells typical of untreated pancreatitis was delayed by PGE1. Mortality rates were unaffected by PGE1.

Methods for assessing the adhesive and locomotory properties of leucocytes are reviewed critically and a suggestion made as to the best strategy for testing an unknown compound on leucocyte behaviour. In particular the distinction is made between reductionist assays, where a single property is being investigated, and realistic assays where an attempt is made to mimic the situation in vivo. The realistic assays are often difficult (or impossible) to interpret in behavioural terms, because more than one cell activity is involved, but such assays (e.g. simple Boyden chambers), used with caution, may be preferable for initial screening, If effects are obvious in an assay of this type then more complex reductionist assays, to determine the cause of the altered behaviour, can be tried. In discussing adhesion, data from a flow-chamber system is presented to show the very rapid changes in adhesiveness when cells encounter an immune complex-coated surface. A fully automated tracking system for obtaining speed and persistence parameters for neutrophils is described, and some of the problems involved in estimating these parameters are illustrated. Movement of neutrophils in collagen gels provides a more realistic model of the environment in which they must operate in vivo, and the effects of incorporating immune complexes into such gels are reported.