Chemotherapy of intermediate- and high-grade non-Hodgkin's lymphomas with an intensive epirubicin-containing regimen

An intensive chemotherapy regimen (EVDAC), including high-dose epirubicin, vincristine, and dexamethasone followed by cyclophosphamide and high-dose cytarabine, was administered to 54 untreated adults with intermediate or high-grade non-Hodgkin's lymphomas (NHL). The median age was 59, 61% were Ann Arbor Stage IV, 57% had "B" symptoms, 50% had serum lactate dehydrogenase greater than 250 U/L, and 48% had masses greater than 7 cm (33% > 10 cm) in diameter. Seventy-six percent of patients attained complete or probable complete remissions. The Kaplan- Meier actuarial failure-free survival at 7 years is 50%, and 59% (32 of 54) of all patients started on therapy remain alive and in first remission at a median of 62+ (range, 49+ to 76+) months from completion of therapy. Nearly all patients developed severe neutropenia. Febrile episodes requiring hospitalization during neutropenia occurred after 56% of courses of epirubicin, vincristine, and dexamethasone and after 9% of courses of cyclophosphamide and cytarabine; 80% of patients were hospitalized at least once. Platelet count nadirs of less than 20,000/microL occurred after only 1 of 146 evaluable courses of epirubicin and after none of the cyclophosphamide/cytarabine courses. Although 8 patients had decreases of at least 0.12 in their left ventricular ejection fractions (5 to below normal levels), none have developed clinically evident congestive heart failure. Clinically significant mucositis occurred after only 8% of courses of high-dose epirubicin. Three deaths from infections and one from hyperkalemia with cardiac arrest occurred during therapy. These results confirm that high remission and sustained, failure-free survival rates can be achieved in patients with aggressive NHL, using high-dose anthracycline-containing chemotherapy regimens. Epirubicin appears to have an advantage over doxorubicin at high doses because of decreased toxicity at a therapeutically equivalent dose. These phase II study results need to be validated in a randomized phase III trial, and growth factors should be used to attempt to reduce the neutropenia-associated complications.     

Magnetic resonance imaging of the brain in very preterm infants: visualization of the germinal matrix, early myelination, and cortical folding

OBJECTIVE: To investigate preterm infants, we have installed in our neonatal intensive care unit a dedicated magnetic resonance (MR) imaging system which was specifically designed for neonatal use. The aim of this study was to describe the MR appearances of the brain in preterm infants who were first scanned between 25 and 32 weeks gestational age (GA) and to outline changes to the brains of these infants between their first scan and term. METHODS: Preterm infants of 25 to 32 weeks GA were imaged using the 1T neonatal MR system (Oxford Magnet Technology, Eyensham, Oxfordshire, England/Picker International, Cleveland, OH). The scanning protocol included T1-weighted conventional spin echo (repetition time [TR], 600; echo time, 20 ms), inversion recovery fast spin echo (TR, 3530; effective echo time, 30; inversion time, 950 ms), and T2-weighted fast spin echo (TR, 3500; effective echo time, 208 ms) sequences. RESULTS: Seventeen infants of median 28 weeks GA (range, 24 to 31 weeks) at birth were imaged a total of 53 times between birth and term. The median number of images per infant was two (range, 1 to 9). In infants of < 30 weeks GA, the germinal matrix was visualized at the margins of the lateral ventricles. It had a short T1 and short T2 and the bulk of it involuted at between 30 and 32 weeks GA. The white matter had a relatively homogeneous low signal except for bands of altered signal (probably originating from regions containing radial glia and migrating cells) which were most apparent anterolateral and posterolateral to the lateral ventricles. Myelination was seen in the posterior brainstem, cerebellum, and region of the ventrolateral nuclei of the thalamus. Infants had very little cortical folding at 25 weeks GA but this developed later in an orderly fashion. CONCLUSION: The neonatal MR system allowed extremely preterm infants to be studied safely with MR imaging. The images acquired demonstrated the germinal matrix, early myelination, and early cortical folding. Evolution of these features was demonstrated with serial studies.     

The presence and release of alpha 2-antiplasmin from human platelets

An antigen immunochemically indistinguishable from plasma alpha 2- antiplasmin, the primary plasmin inhibitor, was detected in human platelets. By radioimmunoassay, 33-114 ng alpha 2-antiplasmin antigen was quantitated in the detergent-soluble extract of 10(9) washed human platelets from 10 normal donors with a mean level of 62 +/- 24 ng/10(9) platelets. Plasma alpha 2-antiplasmin, either in the platelet suspending medium or on the surface of the platelets, could account for less than 8% of the antigen present in the platelet extracts. When stimulated with thrombin, the platelets released alpha 2-antiplasmin antigen without cell lysis, and greater than 85% of the alpha 2- antiplasmin antigen was released at a high thrombin dose. At a lower dose of thrombin, alpha 2-antiplasmin and platelet factor 4 were partially released without concomitant secretion of serotonin. No alpha 2-antiplasmin antigen was detected in extracts or red blood cells, polymorphonuclear leukocytes, and adherent and nonadherent mononuclear cells. Thus, the platelet is the only peripheral blood cell containing significant amounts of alpha 2-antiplasmin.     

The xerocytosis of Hb SC disease

Patients with Hb SC disease were found to have microcytic and hyperchromic red cell indices despite mild reticulocytosis. Iron deficiency anemia was ruled out by the finding of normal serum ferritin levels. In order to determine whether the microcytosis was due to coexistent alpha-thalassemia, restriction endonuclease mapping was performed on genomic DNA extracted from peripheral blood leukocytes. Patients with Hb SC disease had microcytic indices despite the presence of a full complement of four alpha-genes (alpha alpha/alpha alpha), suggesting that the microcytosis may be due to cellular dehydration (or xerocytosis), since the mean corpuscular hemoglobin concentration in Hb SC disease patients was significantly higher than in controls. This possibility was investigated further by the determination of RBC cation content. RBC Na levels were similar in SC and normal red cells. Hb SC RBCs, however, had significantly reduced K levels. These findings show that RBC cation content, and thus cell water, is decreased in Hb SC disease. The decreased RBC K level in the presence of normal cellular Na concentration suggests selective K loss that is not due to inhibition of the Na K pump. Ouabain-insensitive K+ efflux was increased to four times normal in SC cells. Cell dehydration was confirmed by the demonstration of increased high-density RBCs on discontinuous Stractan density gradients and by osmotic gradient ektacytometry. Cellular dehydration and its sequelae were worse in CC erythrocytes and milder in AC cells than in Hb SC red cells. Taken together, these data indicate that in Hb SC disease the RBCs are severely dehydrated and typically microcytic and hyperchromic. Hb SC RBCs seem to be dehydrated due to selective K loss. These findings suggest a functional interrelationship between Hb SC, the red cell membrane, and cation regulation.     

Chimeric plasmid that replicates autonomously in both Escherichia coli and Neurospora crassa.

A hybrid pBR322 plasmid (designated pDV1001) containing two functional Escherichia coli antibiotic resistance genes (kanr and camr) and a qa-2+ gene from Neurospora crassa transforms N. crassa qa-2- mutants to qa-2+ with a frequency of ca. 5 X 10(-5) per regenerated spheroplast (ca. 100 transformants per microgram of plasmid DNA). This plasmid can replicate autonomously without integrating into the N. crassa genome. The autonomously replicating hybrid plasmid was detected in N. crassa transformants by Southern gel hybridizations. DNA from these transformants can be recovered by retransformation back into E. coli aroD recipients and selection for chloramphenicol resistance. These E. coli transformants complement an aroD mutant. The hybrid plasmid DNA present in the E. coli transformants remains unchanged on the basis of DNA restriction enzyme analyses. The original, nonhomokaryotic N. crassa transformants can be maintained on a selective medium, but there is as yet no evidence that the self-replicating plasmid can be transmitted through meiosis. In addition, the self-replicating plasmid often integrates into the N. crassa genome and then is inherited in a generally stable fashion through meiosis. Our findings suggest that this plasmid, or some derivative of it, will prove useful as a routine shuttle vector for cloning genes in N. crassa.     

Competition between plasminogen and tissue plasminogen activator for cellular binding sites

Cellular receptors for plasminogen and tissue plasminogen activator (t- PA) regulate plasminogen activation and cell-associated proteolytic activity. The characteristics of the interactions of both ligands with monocytes and monocytoid cell lines bear certain similarities, including affinity (kd approximately 1 mumol/L) capacity and susceptibility to carboxypeptidase treatment. Therefore, we have undertaken the present study to determine directly whether t-PA and plasminogen share common binding sites on cells. We found that recombinant human single-chain t-PA (rt-PA) could inhibit the binding of 125I-plasminogen to the cells and, conversely, plasminogen could inhibit 125I-rt-PA binding. This relationship was observed with 9 cell types, including both adherent cells and cells in suspension. In addition, under several conditions of cell treatment, plasminogen and t- PA receptor expression was modulated in parallel. Furthermore, molecules that have been implicated as candidate plasminogen receptors, gangliosides, and an alpha-enolase--related molecule, also interacted with t-PA. These results suggest that at least a component of the binding sites for plasminogen is shared with t-PA. Occupancy of these sites by either or both ligand(s) should result in arming the cells with the proteolytic activity of plasmin.     

Identification of BCR/ABL-negative primitive hematopoietic progenitor cells within chronic myeloid leukemia marrow

Chronic myeloid leukemia (CML) is a malignant disorder of the hematopoietic stem cell. It has been shown that normal stem cells coexist with malignant stem cells in the bone marrow of patients with chronic-phase CML. To characterize the primitive hematopoietic progenitor cells within CML marrow, CD34+DR- and CD34+DR+ cells were isolated using centrifugal elutriation, monoclonal antibody labeling, and flow cytometric cell sorting. Polymerase chain reaction analysis of RNA samples from these CD34+ subpopulations was used to detect the presence of the BCR/ABL translocation characteristic of CML. The CD34+DR+ subpopulation contained BCR/ABL(+) cells in 11 of 12 marrow samples studied, whereas the CD34+DR- subpopulation contained BCR/ABL(+) cells in 6 of 9 CML marrow specimens. These cell populations were assayed for hematopoietic progenitor cells, and individual hematopoietic colonies were analyzed by PCR for their BCR/ABL status. Results from six patients showed that nearly half of the myeloid colonies cloned from CD34+DR- cells were BCR/ABL(+), although the CD34+DR- subpopulation contained significantly fewer BCR/ABL(+) progenitor cells than either low-density bone marrow (LDBM) or the CD34+DR+ fraction. These CD34+ cells were also used to establish stromal cell-free long-term bone marrow cultures to assess the BCR/ABL status of hematopoietic stem cells within these CML marrow populations. After 28 days in culture, three of five cultures initiated with CD34+DR- cells produced BCR/ABL(-) cells. By contrast, only one of eight cultures initiated with CD34+DR+ cells were BCR/ABL(-) after 28 days. These results indicate that the CD34+DR- subpopulation of CML marrow still contains leukemic progenitor cells, although to a lesser extent than either LDBM or CD34+DR+ cells.