Demonstration of cellular immunity in chronic myeloid leukaemia using leucocyte migration inhibition assay.

Peripheral blood leucocytes from chronic myeloid leukaemia patients in remission were tested for inhibition of migration in presence of solubilized membrane antigens from leukaemic cells in 15 cases. Eight out of 9 autochthonous combinations (88-8%) and 35/49 allogenic combinations (71-4%) showed inhibition of migration. Antigens prepared from relapse leukaemic cell samples in 4 cases showed inhibition of migration of autochthonous as well as allogeneic remission leucocytes. The same batch of CML antigens inhibited migration of normal leucocytes at the level of 22-2%. The difference between inhibition of migration shown by remission leucocytes and normal leucocytes in presence of CML antigens was statistically significant. Solubilized antigens, similarly prepared from normal leucocytes, showed inhibition of migration of remission leucocytes to the extent of 15% only. The difference between the reactivity of CML remission leucocytes to normal and CML antigens was also statistically significant. No enhancement of migration of remission leucocytes was seen with CML antigens

Interstellar Scintillation of PSR J0437-4715 on Two Scales

We sought to determine the scale of scintillation in the interstellar plasma of PSR J0437-4715. We used the Very Long Baseline Array to obtain scintillation amplitude and phase data, from dynamic spectra at 327 MHz. We observe two scales of scintillation of pulsar PSR J0437-4715, differing by more than an order of magnitude in scintillation bandwidth. The wider-bandwidth scale of scintillation that we observe indicates less scattering for this pulsar than for other nearby pulsars, except for PSR B0950+08.Comment: 7 pages, 4 figures, submitted to Astronomy & Astrophysic

Scintillation measurements of the millisecond pulsar PSR J0030+0451 and pulsar space velocities

Scintillation observations of the nearby single millisecond pulsar (MSP) PSR J0030+0451 were carried out with the Parkes 64m radiotelescope at three different epochs in 1999. From analysis of the dynamic spectrum we obtained the amplitude of the electron density power spectrum log C_N^2 ~= -3.33$ and a scintillation velocity V_iss <~ 15 km s^-1. This result shows that the Shklovskii effect on the spin-down rate \dot P is negligible. We also performed a correlation analysis between pulsar proper motions (V_pm) and scintillation velocities (V_iss) using updated measurements for a sample of 77 objects, 17 of which are MSPs. The full sample shows a correlation coefficient r_s ~= 80% at an extremely high significance level, while for the MSP sub-sample (excluding 2 outliers) we obtain r_s ~= 90%.Comment: 8 pages, LaTeX, 4 EPS figures, accepted for publication on A&

Investigation of Some Physical Properties of Accretion Induced Collapse in Producing Millisecond Pulsars

We investigate some physical characteristics of Millisecond Pulsar (MSP) such as magnetic fields, spin periods and masses, that are produced by Accretion Induced Collapse (AIC) of an accreting white dwarf (WD) in stellar binary systems. We also investigate the changes of these characteristics during the mass-transfer phase of the system in its way to become a MSP. Our approach allows us to follow the changes in magnetic fields and spin periods during the conversion of WDs to MSPs via AIC process. We focus our attention mainly on the massive binary WDs (M > 1.0Msun) forming cataclysmic variables, that could potentially evolve to reach Chandrasekhar limit, thereafter they collapse and become MSPs. Knowledge about these parameters might be useful for further modeling of the observed features of AIC.Comment: 9 Pages, 4 figure