High levels of CD44 expression distinguish virgin from antigen-primed B cells.

The in vitro polyclonal stimulation of B cells through their surface immunoglobulin (Ig) induces substantial increases in CD44 protein levels within 24 hours, whereas other stimuli (e.g., lipopolysaccharide, phorbol 12,13 dibutyrate, and interleukin 4) fail to significantly upregulate CD44. The marked increase in CD44 protein expression on anti-Ig-treated B lymphocytes correlates with an increase in CD44-specific mRNA. Cell sorting experiments with B cells isolated from trinitrophenyl-keyhole limpet hemocyanin-immunized mice demonstrate that both short-term antigen-specific, IgG-secreting cells and long-term antigen-primed B cells are exclusively CD44high. We speculate that the rapid and sustained increase in CD44 expression mediated by surface Ig stimulation may alter the homing properties of antigen-primed B cells.

Variations in the cytoskeletal interaction and posttranslational modification of the CD44 homing receptor in macrophages.

Murine CD44 is a cell surface glycoprotein that is thought to play a role in leukocyte migration. We studied the structure and expression of CD44 on two populations of macrophages: those that reside in the peritoneum of unprimed mice, and those that have been elicited to migrate into the peritoneum by the intraperitoneal injection of agents that cause localized inflammatory responses. Our studies reveal structural variations in both the extracellular and intracellular domains of CD44 expressed by these two macrophage populations. The form of CD44 in elicited macrophages has an apparent molecular mass that is approximately 5 kD greater and more heterogenous than that in resident macrophages. This structural changes is posttranslational, extracellular, and apparently reflects increases in N-linked glycosylation. It is also specific for CD44 and does not occur with several other glycoproteins examined. This novel regulation of glycosylation may play an important role in the ability of CD44 to bind to different substrates, particularly lectin-like ligands. In addition, we demonstrate that CD44 in resident macrophages is divided into two pools, one containing nonphosphorylated, cytoskeletally associated CD44, and one containing phosphorylated, unassociated CD44. In contrast, CD44 on the surface of elicited macrophages does not associate with the cytoskeleton. The attachment of CD44 to the cytoskeleton involves either direct or indirect association with actin. The regulated association of CD44 with the cytoskeleton suggests that it may influence or be influenced by macrophage mobility.

Morphology and anatomy of shoot, root, and propagation systems in Hoffmannseggia glauca.

Hoffmannseggia glauca is a perennial weed that has tubers and root-borne buds. Some authors only consider root tubers without mentioning root-borne buds, while others consider that more anatomic studies become necessary to determine the origin of these structures and to interpret their behaviour. The objectives are: to study the growth form of the plant in order to analyze the ontogeny of its propagation organs, and to study its shoot and root anatomical characters that affect water conductivity. Hoffmannseggia glauca was collected in Argentina. Development of its shoot and root systems was observed. Shoots and roots were processed to obtain histological slides. Macerations were prepared to study vessel members. Primary and lateral roots originate buds that develop shoots at the end of the first year. In winter, aerial parts die and only latent buds at soil surface level and subterranean organs remain. In the following spring, they develop innovation shoots. Roots show localized swellings (tuberous roots), due to a pronounced increase of ray thickness and parenchymatous proliferation in the root center. Root vessel members are wider than those of aerial and subterranean shoots. Early development of an extensive root system, presence of root borne buds, anatomic and physiological specialization of innovation shoots, capability of parenchymatous rays to originate buds and tuberous roots, and high water transport efficiency in subterranean organs lead Hoffmannseggia glauca to display higher colonization potential than other species.

The combined modality therapy of diffuse histology non-Hodgkin's lymphoma with cyclophosphamide, adriamycin, vincristine, prednisone (CHOP) and total body irradiation.

The combination of cyclophosphamide, adriamycin, vincristine, and prednisone (CHOP) alternating with total body irradiation (TBI) has been shown earlier to be effective therapy in patients with malignant lymphoma who have received prior chemotherapy and/or radiation therapy. A limited institutional pilot study was therefore done by the Southwest Oncology Group between October 1977, and November 1978 to test the benefit of this program in previously untreated persons with Stages 3 and 4 diffuse histology non-Hodgkin's lymphoma. Eleven evaluable patients with the following histologies were treated: 7 poorly differentiated, 2 with histiocytic, 1 with mixed lymphoma and 1 with well-differentiated morphology. CHOP was given in the following manner: cyclophosphamide 400 mg/M2 IV day 1, adriamycin 40 mg/M2 IV day 1, vincristine 2 mg IV day 1, and Prednisone 100 mg po daily X 5. Forty-five rad total body irradiation was delivered in three fractions on days 21, 23 and 25. Chemotherapy was repeated on day 42, etc., until four cycles of CHOP and three cycles TBI (135R) were delivered. Responses were seen in 8/11 patients (6 CR and 2 PR); 5 persons are currently alive and 6 are dead. Two of the living patients are alive with disease and the remainder are in unmaintained remission. Two persons died with no response and one died in complete remission of an unrelated illness. The median duration of remission is 15 months and the median survival for all patients is 48 months. The therapy was well tolerated with a mean nadir leukocyte count of 3,020 X 10(9)/microliters (range 1.2-5.5) and a mean nadir platelet count of 188 X 10(9)/microliters (range 016-270). As delivered, this program is capable of producing durable remissions and needs to be verified in a larger series of patients.