Effect of cobalt and chromium ions on bcl-2, bax, caspase-3, and caspase-8 expression in human U937 macrophages

The bcl-2 and caspase families of proteins play a central role in the modulation of apoptosis. The purpose of this study was to analyze the effect of Co(2+) and Cr(3+) ions on the expression of bcl-2, bax, caspase-3 and caspase-8 to better understand the mechanisms leading to ion-induced apoptosis in macrophages. U937 human macrophages were exposed to Co(2+) and Cr(3+) ions. The expression of proteins was measured by Western blot while caspase activities were measured by colorimetric assay. Results show that Co(2+) ions inhibited bcl-2 expression with significant effect (p<0.05) after 16 h and a maximal 52% inhibitory effect after 24 h. Co(2+) stimulated bax expression with a significant stimulation (p<0.05) after 8 h and a maximal 1.75-fold increase after 16 h. Co(2+) also stimulated the expression of the active fragment of caspase-3 as well as caspase-3 activity maximal increase after 24 h. Co(2+) ions had no effect on caspase-8 expression or activity.Cr(3+) ions inhibited bcl-2 expression with significant effect (p<0.05) after 16 h and a maximal 43% inhibitory effect after 24 h. Cr(3+) stimulated bax expression with significant stimulation (p<0.01) after 8h and a maximal 2.25-fold increase after 24 h. Cr(3+) ions also stimulated the expression of the active fragments of caspase-3 and -8, as well as the activities of both proteases. The effect of Cr(3+) ions on the expression of both caspase active fragments was maximal after 16 h incubation. In conclusion, our results suggest that the modulation of the expression of proteins from the bcl-2 and the caspase families of proteins are implicated in the induction of macrophage apoptosis by Co(2+) and Cr(3+) ions.     

Coamplification of 12p11 and 12q13 approximately q22 in multiple ring chromosomes in a spindle cell sarcoma resolved by novel multicolor fluorescence in situ hybridization analysis

An 80-year-old male presented with a lobulated mass in the lower abdominal wall. A diagnosis of an intermediate grade myofibroblastic spindle cell sarcoma was made. Cytogenetic analysis demonstrated a complex karyotype with a der(6), a small marker and five, different in size, ring chromosomes. Fluorescence in situ hybridization (FISH), multiplex FISH, and multicolor banding analysis was used to further delineate this complex karyotype. The der(6) was shown to be a der(18)t(6;18;9;12;18), the marker chromosome was identified as del(17), and the ring chromosomes as r(9) and r(12;18)x4. Amplification of 18 and coamplification of 12p and 12q was detected in the ring and marker chromosomes. No intercellular heterogeneity was observed although a few micronuclei containing chromosome 18 and anaphase bridges, containing chromosome 12 material, the result of bridge-fusion-bridge (BFB) cycles, were observed. Our findings combined with results from others indicate that amplification of chromosomes 12 and 18 as well as BFB phenomena characterize this type of sarcoma.     

Apoptosis of myocytes and proliferation markers as prognostic factors in end-stage dilated cardiomyopathy.

INTRODUCTION: The aim of the study was to evaluate the role of apoptosis, proliferation markers, volume density of interstitium, and myofibril volume fraction for the prognosis in patients with end-stage dilated cardiomyopathy (DCM). METHODS: Endomyocardial biopsy was performed during open-heart surgery in 56 patients with end-stage DCM. Patients were divided into two groups, one group with shorter survival (24+/-9 months, mean+/-S.D.) and another group with survival of more than 7 years after operation. The TUNEL method was used for the detection of apoptosis, and immunohistochemical methods were used for the evaluation of inhibitor of apoptosis (bcl-2) and proliferation markers (PCNA and Ki-67). RESULTS: The increased percentage of apoptotic myocytes, decreased expression of bcl-2, and decreased expression of PCNA and Ki-67 antigen was found in the group with early mortality compared to that with longer survival. Myofibril volume fraction was lower and volume density of interstitium was higher in the group with early mortality compared to that with longer survival. CONCLUSION: Apoptosis, bcl-2 expression, and proliferation activity of myocytes, myofibril volume fraction, and volume density of interstitial tissue might be useful in predicting the prognosis (progressive vs. nonprogressive form) of patients with heart failure due to DCM.     

Loss of cell polarity causes severe brain dysplasia in Lgl1 knockout mice

Disruption of cell polarity is seen in many cancers; however, it is generally considered a late event in tumor progression. Lethal giant larvae (Lgl) has been implicated in maintenance of cell polarity in Drosophila and cultured mammalian cells. We now show that loss of Lgl1 in mice results in formation of neuroepithelial rosette-like structures, similar to the neuroblastic rosettes in human primitive neuroectodermal tumors. The newborn Lgl1(-/-) pups develop severe hydrocephalus and die neonatally. A large proportion of Lgl1(-/-) neural progenitor cells fail to exit the cell cycle and differentiate, and, instead, continue to proliferate and die by apoptosis. Dividing Lgl1(-/-) cells are unable to asymmetrically localize the Notch inhibitor Numb, and the resulting failure of asymmetric cell divisions may be responsible for the hyperproliferation and the lack of differentiation. These results reveal a critical role for mammalian Lgl1 in regulating of proliferation, differentiation, and tissue organization and demonstrate a potential causative role of disruption of cell polarity in neoplastic transformation of neuroepithelial cells.     

Relating cistrons and functions in bacteriophage PM2

An approach to correlate functions with cistrons in bacteriophage PM2 is presented. Two of the temperature-sensitive mutants obtained differed from the wild type in heat sensitivity and four differed in host range. Comparison of the electrophoretic patterns of DNA from cells infected at the restrictive temperature with those obtained in wildtype infection revealed that viral DNA bands were absent with three additional mutants. Complementation analysis assigned the four host range mutants to cistron I and the three mutants defective in DNA synthesis to cistron IV. Recombination frequencies were used to locate cistrons III and IV on the partial genetic map of PM2.     

Functional insights on the polarized redistribution of leukocyte integrins and their ligands during leukocyte migration and immune interactions

Summary:  Cell–cell and cell–matrix interactions are of critical importance in immunobiology. Leukocytes make extensive use of a specialized repertoire of receptors to mediate such processes. Among these receptors, integrins are known to be of crucial importance. This review deals with the central role of integrins and their counterreceptors during the establishment of leukocyte–endothelium contacts, interstitial migration, and final encounter with antigen-presenting cells to develop an appropriate immune response. Particularly, we have addressed the molecular events occurring during these sequential processes, leading to the dynamic subcellular redistribution of adhesion receptors and the reorganization of the actin cytoskeleton, which is reflected in changes in cytoarchitecture, including leukocyte polarization, endothelial docking structure formation, or immune synapse organization. The roles of signaling and structural actin cytoskeleton-associated proteins and organized membrane microdomains in the regulation of receptor adhesiveness are also discussed.