Biomedical subjects
Publications and source records attributed to G Brittinger.
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Pure suspensions of human lymphocytes were separated from peripheral blood by means of nylon wool, homogenized in 0.34 M sucrose-0.01 M EDTA solution, and fractionated by differential centrifugation. The bulk of acid hydrolase activity was found to be concentrated in a 20,000 g x 20 min granular fraction, whereas nuclear, debris, and supernatant fractions contained lesser concentrations of hydrolases. Acid hydrolase activity present in the granular fraction showed appropriate "latency" as judged by its dose-dependent release into the 20,000 g x 20 min supernatant after exposure to membrane-disruptive agents such as streptolysin S, filipin, and lysolecithin. Heparin proved to be necessary in the suspending medium so that reproducible homogenization and cell fractionation could be obtained. Even excessive contamination of lymphocyte suspensions with platelets did not appreciably alter the acid hydrolase activity of lymphocyte homogenates or the distribution of enzymes in subcellular fractions. Discontinuous density-gradient centrifugation of a 500 g x 10 min supernatant, containing both acid hydrolase-rich organelles and mitochondria, resulted in partial resolution of hydrolase-rich organelles from mitochondria. Fine structural studies of the intact lymphocytes showed the presence of acid phosphatase-positive, membrane-bounded organelles. Electron microscopy of the "large granule" (20,000 g x 20 min) fraction of such lymphocytes demonstrated 80-90% mitochondria, 5-10% platelets, and 5-10% membrane-bounded acid phosphatase-positive structures. The data indicate the presence in human peripheral blood lymphocytes of acid hydrolase-rich granules which possess many of the biochemical and structural characteristics of lysosomes in other tissues.
Subcellular fractions were isolated by differential centrifugation from pure suspensions of human blood lymphocytes incubated with and without phytohemagglutinin (PHA). Between 30 and 120 min after addition of PHA to intact cells, redistribution of acid hydrolases (beta glucuronidase, acid phosphatase), from a 20,000 g x 20 min granular fraction into the corresponding supernatant, was observed. No increase in total acid hydrolase activity was found at these times. The mitochondrial marker enzyme, malate dehydrogenase, did not undergo redistribution. Granules derived from PHA-treated cells became more fragile upon subsequent incubation with membrane-disruptive agents in vitro (streptolysin S, filipin). These changes were associated with an increase in the over-all permeability of the stimulated cell to substances in the surrounding medium, such as neutral red. Augmentation of dye entry into lymphocytes required intact metabolism as judged by response to temperature and inhibitors (cyanide, antimycin A, 2,4-dinitrophenol). PHA, however, did not release enzyme activity from hydrolase-rich granules in vitro or render them more susceptible to subsequent challenge with membrane-disruptive agents. These studies suggest that PHA induces early changes in the surface of lymphocytes. The consequent redistribution of acid hydrolases may play a role in remodeling processes of the stimulated cells.
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Clinical and prognostic relevance of the Kiel classification of non-Hodgkin lymphomas (NHL) was investigated in 1127 patients entering a prospective multicenter observation study. Survival of the 782 (69.4 per cent) patients with low-grade malignant NHL (lymphocytic lymphomas, predominantly B-CLL, LP immunocytoma, centrocytic lymphoma, centroblastic-centrocytic lymphoma) exceeded that of the 341 patients (30.2 per cent) with high-grade malignant NHL (centroblastic, immunoblastic, lymphoblastic lymphomas). Prognosis was best in centroblastic-centrocytic lymphoma and in B-CLL and least favorable in immunoblastic and lymphoblastic lymphomas. Survival of LP immunocytoma and centrocytic lymphoma patients was intermediate after 2 to 2.5 years of follow-up. Corresponding to histopathology, pattern of survival curves of low-grade malignant NHL (slow decline, no plateauing) differed from that of high-grade malignant NHL (rapid decline, subsequent plateauing). Prognosis of B-CLL was superior to that of LP immunocytoma. Stages I and II were more frequent in centroblastic-centrocytic lymphoma (21 per cent) than in LP immunocytoma (2.5 per cent) and centrocytic lymphoma (11 per cent). Ability of radiotherapy to induce stable complete remissions in stage III of centroblastic-centrocytic lymphoma indicates prolonged restriction of lymphoma to the lymphatic system. In immunoblastic and centroblastic lymphomas, stages I and II were diagnosed in 34 and 38 per cent of cases, respectively, but only in stage I/IE of centroblastic lymphoma prolonged remissions were achieved by radiotherapy. In advanced high-grade malignant NHL marked improvement of prognosis was solely possible by induction of complete remissions whereas in corresponding low-grade malignant lymphomas also partial remissions were prognostically relevant.
Alcaligenes xylosoxidans subsp. xylosoxidans (A. x. xylosoxidans) is a nonfermenting gram-negative peritrichous rod and opportunistic pathogen. The organism is frequently found in an aqueous environment. In the past few years, nosocomial infections caused by A. x. xylosoxidans have become more evident. The literature suggests that systemic infections are severe and often lethal and an optimal antibiotic therapy is not well established. This report describes nosocomial infections in 11 patients of a hematology ward over a 2-month period. Primary infection occurred during the neutropenic phase after cytotoxic chemotherapy. Reinfection spread from central venous catheters that had been implanted before the first infection. The bacteremia was successfully treated by imipenem. None of the 11 patients died from the bacteremia, but 3 died of their underlying diseases. Despite an intensive search for the source, the route of infection remained uncertain. Nosocomial infections by A. x. xylosoxidans are of growing importance in high-risk patients. Although the source of infection often remains unknown, infection seems to originate from contaminated solutions. Treatment with imipenem and the removal of central venous catheter systems successfully eliminated A. x. xylosoxidans, which adheres to plastic material.
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