Biomedical technology, socioeconomics, and biomedical computing: implications for change.

Pathology and laboratory medicine have changed rapidly since 1945. Three forces can be recognized as major vectors for change: rapid application of the biotechnology evolving from research in molecular biology, radically changing medical socioeconomics, and the evolving field of medical information science. While these apparently disparate elements affect all of medicine and health care, at the present time they appear to be changing pathology and laboratory medicine to a far greater extent than many other medical specialties. If pathologists fail to make the necessary changes, obsolescence may well overtake the specialty. Planning for the innovative educational and training programs that will be required to meet the future demands of the specialty is essential, not only for those now in practice but for those who will follow us.

Hemostatic imbalances produced by plasma exchange.

Ten patients who underwent intensive therapeutic plasma exchange were studied prospectively to determine the nature and extent of changes induced in their coagulation mechanisms. The patients' plasma was replaced with serum albumin and normal saline. Significant changes were noted acutely in the prothrombin time, activated partial thromboplastin time, plasma fibrinogen, and platelet counts. Chronically, significant decreases were found in plasma fibrinogen concentrations and platelet counts. Intensive plasma exchange with fluids devoid of coagulation factors results in defects in the normal hemostatic mechanism.

Spontaneous thyroiditis in BB Wistar diabetic rats.

Spontaneous lymphocytic thyroiditis was observed at necropsy in 36 BB Wistar diabetic rats (63.2%) and in eight of their nondiabetic siblings (42.1%). The incidence of thyroiditis decreased both with age and with longer duration of diabetes. All rats with pancreatic insulitis (a manifestation of the onset of diabetes) also had thyroiditis. BB Wistar rats with insulitis had more severe lymphocytic thyroiditis, characterized by lymphocytic, plasmacytic, and macrophage infiltration of thyroid interstitium and follicles. A milder, mostly perivascular and interstitial lymphocytic thyroiditis was characteristic of lesions in rats which did not have insulitis. The histological appearance of the thyroiditis suggests that these rats may be subject to autoimmune disease at the onset of diabetes which involves sites other than just the pancreas.

Immune system changes in cytapheresis donors.

In vitro measurements of several variables of the immune system were made in 21 healthy donors who had been subjected to frequent cytapheresis an a group of whole blood donor controls matched for age and sex. Significant changes noted in the apheresis donors compared to controls included a 23 percent lower mean absolute lymphocyte count (p less than .01), a 25 percent lower mean T cell count (p less than .01), and a 46 percent lower mean B cell count (p less than .001). Serum protein changes included a 27 percent lower mean gamma globulin level (p less than .01), and 14 percent lower mean IgG level (p less than .05) in the apheresis donors when compared to the control group. The possible implications of these findings are discussed, and we suggest that donors undergoing multiple cytapheresis procedures be closely monitored to determine the safe donation frequency.

Further improvement of the enzyme-linked antiglobulin test (ELAT) for erythrocyte antibodies.

The enzyme-linked antiglobulin test (ELAT) was found to be nine times more sensitive than the direct antiglobulin test (DAT) in detecting erythrocytes sensitized by IgG antibody in vitro. The release of hemoglobin and other interfering substances from the erythrocytes gave falsely high absorbance values which were corrected by the use of a hemolysis bland with each test. ELAT results showed good precision. With the use of the hemolysis blank, the ELAT should prove to be a useful tool for hospital blood blanks in the detection of weakly reactive allo- and autoantibodies.

Transfusion significance of Lewis system antibodies. Success in transfusion with crossmatch-compatible blood.

Patients with nonhemolytic Lewis antibodies in the serum were transfused on the basis of major crossmatch compatibility alone. No adverse clinical affects were noted when 33 such patients received a total of 230 transfusions. Considerable savings in technologist time and reagent cost were realized by adopting this policy. Transfusion on the basis of crossmatch compatibility alone did not necessarily result in the selection of Le(a-) and/or Le(b-) blood for patients with corresponding antibodies in the serum. Crossmatch compatibility ratio for patients with anti-Leb in the serum was much higher than expected and was profoundly affected by the ABO group of the donors.

Clinical laboratory determination of antithrombin III. A new semi-automated method.

A new, semi-automated method for determination of antithrombin III activity in the clinical laboratory is presented. The assay is performed utilizing the chromogenic substrate S-2238 and the ABA-100. Results are expressed in arbitrary units of activity; thus, construction of standard curves with interpolation of values is not necessary. The assay has a low day-to-day coefficient of variation (6%), is insensitive to heparin, and gives reliable results in a variety of clinical situations known to affect antithrombin III activity.

Subclinical hemolytic disease of the newborn due to anti-e.

A case of subclinical hemolytic disease of the newborn resulting in reticulocytosis and positive direct and indirect antiglobulin tests in an infant both ABO- and Rh(D)-compatible with its mother is reported. The antibody was an IgG, non-complement-binding molecule present in low titer with a low avidity for the antigen, acted optimally in enzyme systems, did not manifest dosage effect, and caused slight extravascular destruction of fetal erythrocytes. Routine antibody screening of all pregnant women should be performed and neonatal cord blood specimens analyzed to avoid unexpected infant morbidity and mortality, and to characterize hemolytic disease of the newborn due to rare atypical antibodies more fully.

Ultrastructure of lymphocyte tumor cell interaction with localization of cell-bound antibody by ferritin labeling.

Splenic lymphocytes derived from Walker carcinoma-bearing rats were harvested and incubated with Walker carcinoma cells growing in tissue culture. The sequence of events leading to target cell death was studied by phase microscopy and scanning and transmission electron microscopy. The sensitized lymphocytes adhere to the tumor cells by multiple cytoplasmic appendages, but no ultrastructural changes are seen at this interface. After 1 hr these lymphocytes release cytoplasmic components consisting of membrane-lined vesicles, cell membranes, endoplasmic reticulum, and cytoplasmic material. This material adheres closely to the surface of the tumor cells and is subsequently seen within the cytoplasm of the tumor cell. The tumor cells then undergo degenerative changes and cell death occurs in 24 to 36 hr. The lymphocyte-derived material appears to contain immunoglobulin components as determined by specific ferritin labeling.