The high affinity of antibodies produced during responses to T-cell-dependent antigens is associated with somatic mutation in the variable region of the immunoglobulin. Indirect evidence indicates that: (1) this arises by a process of hypermutation, acting selectively on rearranged immunoglobulin variable-region genes, which is activated in centroblasts within germinal centres; and (2) centrocytes, the progeny of centroblasts, undergo selection on the basis of their ability to receive a positive signal from antigen. We have now performed experiments analysing this selection process, and found that, on culture, centrocytes isolated from human tonsil kill themselves within a few hours by apoptosis. This is not a feature of other tonsillar B cells. Centrocytes can be prevented from entering apoptosis if they are activated both through their receptors for antigen and a surface glycoprotein recognized by CD40 antibodies.

All patients with myeloma at diagnosis and at disease assessment should have serum creatinine, estimated glomerular filtration rate, and electrolytes measurements as well as free light chain, if available, and urine electrophoresis of a sample from a 24-hour urine collection (grade A). The Chronic Kidney Disease Epidemiology Collaboration, preferably, or the Modification of Diet in Renal Disease formula should be used for the evaluation of estimated glomerular filtration rate in patients with stabilized serum creatinine (grade A). International Myeloma Working Group criteria for renal reversibility should be used (grade B). For the management of RI in patients with multiple myeloma, high fluid intake is indicated along with antimyeloma therapy (grade B). The use of high-cutoff hemodialysis membranes in combination with antimyeloma therapy can be considered (grade B). Bortezomib-based regimens remain the cornerstone of the management of myeloma-related RI (grade A). High-dose dexamethasone should be administered at least for the first month of therapy (grade B). Thalidomide is effective in patients with myeloma with RI, and no dose modifications are needed (grade B). Lenalidomide is effective and safe, mainly in patients with mild to moderate RI (grade B); for patients with severe RI or on dialysis, lenalidomide should be given with close monitoring for hematologic toxicity (grade B) with dose reduction as needed. High-dose therapy with autologous stem cell transplantation (with melphalan 100 mg/m(2) to 140 mg/m(2)) is feasible in patients with RI (grade C). Carfilzomib can be safely administered to patients with creatinine clearance > 15 mL/min, whereas ixazomib in combination with lenalidomide and dexamethasone can be safely administered to patients with creatinine clearance > 30 mL/min (grade A).

Limited response to idiotype vaccination in patients with myeloma suggests that there is a need to develop better immunotherapy strategies. It has been determined that the number of high-potency CMRF44 ؉ CD14 ؊ CD19 ؊ dendritic cells (DCs) in the blood of patients with myeloma (range, 0.03%-0.8% of mononuclear cells [MNCs]; n ‫؍‬ 26) was not significantly different from that in controls (range, 0.05%-0.8% of MNCs; n ‫؍‬ 13). Expression of the costimulatory molecules CD80 and CD86 on DCs from these patients (mean, 29%؎17% of MNCs and 85%؎10% of MNCs, respectively) was also normal (mean, 29%؎17% and 86%؎16% of MNCs, respectively). Up-regulation of CD80 expression in response to stimulation by human (hu)CD40LT ؉ interleukin (IL)-2 was significantly reduced on the DCs of patients with myeloma during stable disease (n ‫؍‬ 9) and was absent during progressive stages (n ‫؍‬ 7) of disease. Similar effects were seen on B cells but not on monocytes of the same group of patients. CD86 expression on DCs was high before (86%) and after (89%)

No abstract

High-dose cytarabine (ara-c) may overcome cytarabine resistance in leukemic blasts. It has been used as a successful salvage and in postremission therapy but not as initial induction treatment. Patients aged 15 to 60 years, presenting with newly diagnosed acute myeloid leukemia (AML) were randomized to receive either high-dose cytarabine, 3 g/m2 12 hourly on days 1, 3, 5, and 7 for 8 doses, daunorubicin 50 mg/m2 days 1 to 3, etoposide 75 mg/m2 days 1 to 7, (HIDAC-3–7) or standard dose cytarabine 100 mg/m2 continuous intravenous infusion for 7 days with daunorubicin and etoposide at the same dose and schedule as above (7–3–7). Patients could receive a second or third induction course if complete remission (CR) was not achieved. All patients received the same postinduction consolidation therapy (5–2–5) for 2 courses. Eligible patients had no prior chemotherapy or myelodysplastic disease. Patients have been followed for a median of 4.5 years. Of 301 patients treated, complete response (CR) was achieved in 71% with HIDAC- 3–7 and 74% with 7–3–7. For patients in CR, the estimated median remission duration was 45 months with HIDAC-3–7 and 12 months with 7–3– 7 (P = .0005 univariate analysis, P = .0004 multivariate analysis). The estimated percentage of patients relapse free 5 years after achieving a CR was 49% on HIDAC-3–7 and 24% on 7–3–7. Patients in CR tended to survive longer with HIDAC-3–7 but there were no overall survival differences between the two arms. HIDAC-3–7 was associated with significantly more toxicity in induction with more leukopenia, thrombocytopenia, nausea, and vomiting and eye toxicity (all P < .001) but a similar incidence of severe central nervous system and cerebellar toxicity compared to 7–3–7. The consolidation treatment was the same in both arms but caused significantly more leukopenia and thrombocytopenia in patients previously treated with HIDAC-3–7 induction (P < .0001). We conclude that a dose-effect exists for cytarabine in AML and that HIDAC- 3–7 prolongs remission duration and disease-free survival and is tolerable when used as initial induction therapy in patients with de novo AML.

Of binocularly-activated striate neurons only a proportion have their two receptive fields in exactly corresponding positions in the eontralateral hemifield. Those which are not corresponding are said to show receptive field disparity. Because the eyes diverge in the anaesthetized and paralyzed preparation, the binocular receptive fields are horizontally separate. With increasing retinal eccentricity there is a gradual decrease in this horizontal separation as well as progressive changes in the local receptive field disparities. With increasing horizontal retinal eccentricity there is a progressive increase in horizontal receptive field disparities together with a smaller decrease in vertical disparities. Receptive field disparities are relatively unaffected by increasing vertical retinal eccentricity.A neurophysiological theory for binocular single vision and depth discrimination is put forward as a theoretical framework for the construction of the horopter for the cat as well as a region analogous to Panum's fusional area in man.Observations have been made on the responses, particularly to moving slit stimuli, of units with peripherally-located receptive fields. For several binocular units it was possible to study the full range of the binocular interaction when the two receptive fields were moved from exact correspondence to positions of increasing non-alignment.

No abstract

The value of administering sequential courses of chemotherapy containing highdose cytarabine in both induction and consolidation therapy for acute myeloid leukemia (AML) has not been assessed in a prospective randomized trial. Two hundred ninety-two AML patients aged 15 to 60 years were enrolled in the Australasian Leukaemia and Lymphoma Group (ALLG) AML trial number 7 (M7) protocol to evaluate this question. All received induction therapy with the ICE protocol (idarubicin 9 mg/ m 2 ؋ 3; cytarabine 3 g/m 2 twice a day on days 1, 3, 5, 7; etoposide 75 mg/m 2 ؋ 7). Complete remission was achieved in 234 (80%) patients. Two hundred two patients in remission were then randomized to either a further identical cycle of ICE or 2 attenuated courses (cytarabine 100 mg/m 2 daily ؋ 5, idarubicin ؋ 2, etoposide ؋ 5 [IcE]). ICE consolidation therapy was more toxic than IcE, however, the treatment-related death rate was not significantly different. There was no difference between the 2 consolidation arms for relapse-free survival at 3 years (49% for ICE vs 46% for IcE; P ‫؍‬ .66), survival following randomization (61% vs 62%; P ‫؍‬ .91), or the cumulative incidence of relapse (43% vs 51%; P ‫؍‬ .31), and there was no difference within cytogenetic risk groups. Intensive induction chemotherapy incorporating high-dose cytarabine results in high complete remission rates, but further intensive consolidation treatment does not appear to confer additional benefit. (Blood. 2005;105:481-488)