A prospective investigation of cell dose in single-unit umbilical cord blood transplantation for adults with high-risk hematologic malignancies.

Umbilical cord blood (UCB) as an allogeneic transplant source is generally limited to units with pre-cryopreservation total nucleated cell (TNC) doses ⩾2.5 × 10(7) NC/kg. We prospectively investigated single UCB transplantation, with cord units as low as 1 × 10(7) NC/kg, all processed with post-thaw albumin-dextran dilution. We transplanted 104 adult patients with 84% having relapsed/refractory disease. The median TNC dose was 2.1 × 10(7) NC/kg (range: 1.0-4.4 × 10(7)) and median CD34+ cell dose was 1.0 × 10(5)/kg (range: 0.0-3.7 × 10(5)/kg). Post-manipulation cell recovery and viability were 96% and 99%, respectively. Median times to neutrophil and platelet engraftment were 16 and 43 days, respectively. Univariate factors predicting neutrophil engraftment included TNC (P=0.03) and CD34+ cell dose (P=0.01). CD34+ dose predicted platelet engraftment (P<0.001). In multivariate analysis, CD34+ dose remained significant for neutrophil and platelet engraftment (P<0.0001 and P<0.0001, respectively). The 100-day and 1-year overall survival were 70% and 46%, respectively (95% confidence interval: 36%-56% at 1 year). The subset transplanted with 1-1.5 × 10(7) NC/kg had similar 100-day and 1-year survivals of 73% and 45%, respectively. Single-unit UCB transplantation using small units, processed as described, leads to favorable engraftment and acceptable outcomes in poor prognosis patients. CD34+ cell dose (⩾1.5 × 10(5)/kg) helps predict faster engraftment and can aid in graft selection.

Search for the Θ+ pentaquark via the π(-)p→K(-)X reaction at 1.92 GeV/c.

The Θ(+) pentaquark baryon was searched for via the π(-)p→K(-)X reaction with a missing mass resolution of 1.4 MeV/c(2) (FWHM) at the Japan Proton Accelerator Research Complex (J-PARC). π(-) meson beams were incident on the liquid hydrogen target with a beam momentum of 1.92 GeV/c. No peak structure corresponding to the Θ(+) mass was observed. The upper limit of the production cross section averaged over the scattering angle of 2° to 15° in the laboratory frame is obtained to be 0.26 µb/sr in the mass region of 1.51-1.55 GeV/c(2). The upper limit of the Θ(+) decay width is obtained to be 0.72 and 3.1 MeV for J(Θ)(P)=1/2(+) and J(Θ)(P)=1/2(-), respectively, using the effective Lagrangian approach.

Evidence for heavy hyperhydrogen (Λ)(6)h.

Evidence for the neutron-rich hypernucleus (Λ)(6)H is presented from the FINUDA experiment at DAΦNE, Frascati, studying (π+,π-) pairs in coincidence from the K(stop)(-) + (6)Li →(Λ)(6)H + π+ production reaction followed by (Λ)(6)H → (6)He + π- weak decay. The production rate of (Λ)(6) undergoing this two-body π- decay is determined to be (2.9 ± 2.0) × 10(-6)/K(stop)(-). Its binding energy, evaluated jointly from production and decay, is BΛ((Λ)(6)H) = (4.0 ± 1.1) MeV with respect to (5)H+Λ. A systematic difference of (0.98 ± 0.74) MeV between BΛ values derived separately from decay and from production is tentatively assigned to the (Λ)(6)H 0(g.s.)(+) → 1+ excitation.