Effect of antimony-oxide on the shielding properties of some sodium-boro-silicate glasses.

Some sodium-silicate-boro-antimonate glasses having the molecular composition [(20) Na2O - (20) SiO2 - (60-x) B2O3 - (x) Sb2O3 (where x takes the values 0, 5 … or 20)] have been prepared by the melt quenching method. The melting and annealing temperatures were 1500 and 650K respectively. The amorphous nature of the prepared samples was confirmed by using X-ray diffraction analysis. Both the experimental and empirical density and molar volume values showed gradual increase with increasing Sb2O3 content. The empirical densities showed higher values than those obtained experimentally, while the empirical molar volume values appeared lower than those obtained experimentally, which confirm the amorphous nature and randomness character of the studied samples. The experimentally obtained shielding parameters were approximately coincident with those obtained theoretically by applying WinXCom program. At low gamma-ray energies (0.356 and 0.662MeV) Sb2O3 has approximately no effect on the total Mass Attenuation Coefficient, while at high energies it acts to increase the total Mass Attenuation Coefficient gradually. The obtained Half Value Layer and Mean Free Path values showed gradual decrease as Sb2O3 was gradually increased. Also, the Total Mass Attenuation Coefficient values obtained between about 0.8 and 3.0MeV gamma-ray energy showed a slight decrease, as gamma-ray photon energy increased. This may be due to the differences between the Attenuation Coefficients of both antimony and boron oxides at various gamma-ray photon energies. However, it can be stated that the addition of Sb2O3 into sodium-boro-silicate glasses increases the gamma-ray Attenuation Coefficient and the best sample is that contains 20 mol% of Sb2O3, which is operating well at 0.356 and 0.662MeV gamma-ray.

Cyclosporine-associated seizures in bone marrow transplant recipients given busulfan and cyclophosphamide preparative therapy.

Five of 182 recipients of allogeneic bone marrow transplants performed between 2/84 and 6/90 developed seizures while receiving cyclosporine and methylprednisolone to prevent acute graft-versus-host disease. All received a radiation-free regimen of busulfan and cyclophosphamide as preparative therapy. Two patients received HLA-mismatched allografts; and three patients received marrow from HLA-identical sibling donors. Two patients had received extensive intrathecal therapy prior to transplantation. All patients were receiving standard prophylactic doses of CsA and MP at the time of onset (median 31 days posttransplantation) of seizures. Three patients had mild-to-moderate hypertension and varying degrees of morphologic evidence of microangiopathic hemolytic anemia. None had unusually low magnesium levels. Cyclosporine levels were not in the toxic range. Cranial magnetic resonance imaging and computed tomography (CT) showed bilateral abnormalities primarily in the posterior temporal, occipital, and parietal lobes. These abnormalities were shown to be transient on sequential MRI exams in two patients. Seizures as well as radiologic abnormalities resolved on stopping CsA and did not recur in 2 patients who subsequently received CsA in lower doses. These findings confirm and expand previous observations of CsA-associated seizures and demonstrate that they occur in allogeneic bone marrow transplant recipients following a radiation-free preparative regimen of busulfan and cyclophosphamide.