Antigenic characterization of a T-CLL with heteroantisera and monoclonal antibodies: evidence for the T cell lineage of an Ia-positive, Fc-IgG--positive, suppressor-cell subpopulation

In a previous report, peripheral blood mononuclear T cells from a patient with T-chronic lymphocytic leukemia (T-CLL) were shown to bear receptors for the Fc portion of IgG (T gamma). Moreover, the ability of these cells to rosette with sheep erythrocytes was strongly inhibited by a preincubation of the cells with theophylline. These data indicated that they represent a highly purified subpopulation of Fc-IgG receptor-positive, low-affinity rosetting cells with in vitro suppressor activity on lectin-induced proliferation of normal lymphocytes. They also were reactive in antibody-dependent cell-mediated cytotoxicity but had no reactivity in natural killer cell assays. These cells were studied in this report with several heteroantisera and monoclonal antibodies. Results indicate that these T-CLL cells express a T cell antigenic pattern (OKT-3+) and the majority are Ia positive. They also react with the OKT-8 reagent (a reagent detecting the subset of T cells that contains the cytotoxic/suppressor cells), whereas they are negative with OKT-4 (which reacts with the subset of T cells that contains helper cells) and OKT-6 (thymocyte) antibodies. Heteroantisera also support the results obtained with monoclonal reagents. Despite some recent evidence showing that a high percentage of T gamma cells may belong to the monocyte-myeloid lineage, these T-CLL cells were negative with OKM-1, a monoclonal antibody reported to detect a monomyeloid antigen. These results suggest that a distinct subpopulation of suppressor T cells can be identified by membrane-marker phenotyping.     

Spatial patterns in population conflicts

We consider a dynamical model for evolutionary games, and enquire how the introduction of diffusion may lead to the formation of stationary spatially inhomogeneous solutions, that is patterns. For the model equations being used it is already known that if there is an evolutionarily stable strategy (ESS), then it is stable. Equilibrium solutions which are not ESS's and which are stable with respect to spatially constant perturbations may be unstable for certain choices of the dispersal rates. We prove by a bifurcation technique that under appropriate conditions the instability leads to patterns. Computations using a curve-following technique show that the bifurcations exhibit a rich structure with loops joined by symmetry-breaking branches.     

Bacterial α2-macroglobulins: colonization factors acquired by horizontal gene transfer from the metazoan genome?

Background  

Invasive bacteria are known to have captured and adapted eukaryotic host genes. They also readily acquire colonizing genes from other bacteria by horizontal gene transfer. Closely related species such as Helicobacter pylori and Helicobacter hepaticus, which exploit different host tissues, share almost none of their colonization genes. The protease inhibitor α₂-macroglobulin provides a major metazoan defense against invasive bacteria, trapping attacking proteases required by parasites for successful invasion.     

Intimal pulmonary artery sarcoma presenting as dyspnea: case report

Background

We report a case of pulmonary sarcoma which is a rare cause of the common symptom of dyspnea.

Case presentation

A fifty-one year old previously healthy male presented to the emergency room with complaints of dyspnea on exertion. A cardiac workup including an exercise stress test was negative but an echocardiography showed pulmonary stenosis. Cardiac MRI showed a large mass extending from the pulmonic valve to both the right and left pulmonary arteries suggestive of sarcoma. A complete resection and repair of the pulmonary artery was done and adjuvant chemotherapy with doxorubicin and ifosfamide was recommended. The patient is currently disease free after eighteen months.

Conclusion

Pulmonary artery sarcomas are a difficult diagnosis. The diagnosis may remain elusive for some time until the proper imaging techniques are utilized to make a diagnosis. Earlier and accurate diagnosis may lead to earlier interventions and improve survival.