New developments in Emit enzyme immunoassays

New developments in Emit enzyme immunoassays

198 ROYAL COLLEGE OF PATHOLOGISTS OF AUSTRALIA Pathology (1978), 10, April morphologically identical to whole serum. The components of mucinous int...

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198

ROYAL COLLEGE OF PATHOLOGISTS OF AUSTRALIA

Pathology (1978), 10, April

morphologically identical to whole serum. The components of mucinous intimal thickening were the same as those in onion-skin intimal thickening but with lakes of electron-lucent material. Fibro-cellular intimal thickening consisted of layers of elastin, collagen and condensed basement membrane with scattered persisting myointimal cells. Endothelial cell swelling and organelle degeneration was common and endothelial proliferation was not seen. These findings were most consistent with the view that the vascular changes resulted from a process of insudation of luminal constituents into the intima, with subsequent organization and healing. The spectrum of changes from acute fibrinoid necrosis to healed fibro-elastic lesionsdepended on the acuteness ofthe injury and the duration of the healing phase. Luminal thrombosis was an uncommon and terminal event and organization of the thrombi was not an important factor in the development of intimal lesions. A parallel study of S cases of the haemolytic-uraemic syndrome and 4 of systemic sclerosis revealed lesions which were indistinguishable from those of malignant hypertension.

NEW DEVELOPMENTS IN EMIT ENZYME IMMUNOASSAYS

LEUTE,RICHARDPalo .4/to. California The Homogeneous Enzyme lmmunoassays have in the past been used to determine drugs of abuse in urine. Later the system was expanded to include the quantitative determination of antiepileptic drugs in less than 1 min in microliters of serum or plasma. The Emit technology can also be used for the determination of digoxin. Recently a new principle was found which allows the determination of T-4 in serum or plasma. When T-4 is conjugated to pig mitochondria1 malate dehydrogenase. the enzymatic activity is inhibited. Upon addition of anti T-4 antibodies. the enzyme becomes reactivated. This system has been used to develop an Emit T-4 assay employing the ABA- 100 as analyser. It was evaluated in 5 laboratories. A good correlation coefficient with existing methods was found. The coefficient of variation for all concentrations is below 5"". Recovery of added T-4 between 94 and 100°, is found. More than 70 sampleslh can be dealt with. THE APPLICATION OF SCANNING ELECTRON MICROSCOPY IN EXPERIMENTAL AND CLINICAL HAEMATOLOGY

LYTTOS,D. G.. RICHARD,K . A. & YUEN,E. Departnzerit of Pathology, University of Sydney und Department of' ha emu to log^^, Roya! Prince Aljired Hospital A method is described for the examination of the surface morphology of leucocytes obtained from either peripheral blood or bone marrow. It enables individual cells to be examined sequentially by light and scanning electron microscopy (SEM). This method goes some way towards solving the problem of identification ofcells seen by SEM. The method has been applied to a number ofclinical problems including 2 cases of hairy cell leukaemia. The surface morphology of these cells is discussed. The method has also been applied to cells derived from colonies obtained after culture of bone marrow in nutrient agar. The more general application of SEM to morphological analysis in haematology research is discussed with particular reference to the examination of pure cell populations of marrow cells obtained after both discontinuous albumin gradient and velocity cell sedimentation methods of cell separation and fractionation. Some preliminary observations on the feasibility ofcombined scanning and transmission EM are discussed as well as the possible applications of analytical electron microscopy by X-ray probe microanalysis. HEMATRAK AUTOMATED DIFFERENTIAL COUNTER

LEVINE, MARSHALLGeometric Data Corporation. Wayne, Pennsylimia The pattern recognition approach to automated differential counting will be described with emphasis on functional and clinical experience. Hematrak installations in over 75 institutions have demonstrated a capacity of from 35-SO specimensih. Several recent evaluations indicate e z d e n t correlation with reference methods. Experience with different preparation techniques indicates that the Syftem has the flexibilityto accept both fingerstick and EDTA specimens and that films can be prepared either manually or by machine. The Miniprep. a portable automatic smearing instrument will be described as a means of improving specimen qualit) without the need for manual skills. New developments, including RBC morphology, platelets and reticulocyte counting, will also be discussed. Current research into morphological parameters is pointing towards new indices of left shift and lymphocyte atypia.