Hematopoietic cell transplantation in the twitcher mouse. The effects of pretransplant conditioning with graded doses of busulfan

The effects of congenic hematopoietic cell transplantation (HCT; transplantation of bone marrow and spleen cells) after graded doses of busulfan (BU), a myeloablative but nonimmunosuppressive alkylating agent, were evaluated in the twitcher mouse model of human galactosylceramidase deficiency, a demyelinating sphingolipid storage disease. C57BL/6 twitcher mice (immunophenotype Ly-5.1) were given 10 to 50 mg/kg of BU or total-body irradiation (9.0 Gy) at age nine days and HCT from congenic Ly-5.2 donors 24 hr later. The 30-day post-HCT survival, an indicator of tolerance of the preparative regimen, was at least 83% in twitcher mice given 45 mg/kg or less of BU, was 50% in recipients of 50 mg/kg BU and 75% in TBI-conditioned twitchers. The lifespan of twitcher mice given HCT after 10 or 20 mg/kg of BU was similar to that of untreated twitchers (median survival, 42 days; range, 30-47). In contrast, mice transplanted after 35 to 50 mg/kg of BU had significantly prolonged survival (median, 82 days; range, 56-208) and stabilization of hindlimb paralysis, similar to TBI-conditioned recipients. Post-HCT repopulation by donor Ly-5.2 cells was determined by flow cytometry. Thirty days after HCT, only 11-15% of lymphohematopoietic cells in blood, bone marrow, and spleens were of Ly-5.2 donor origin in twitcher mice transplanted after 10 mg/kg of BU but 60-80% were of Ly-5.2 donor origin in mice transplanted after higher doses of BU. These levels further increased to 70-90% by 90 days after HCT, comparable to that seen after TBI. Levels of galactosylceramidase in livers, spleens, and brains of twitchers transplanted after 35-50 mg/kg of BU or after TBI increased to 30-116% of normal control values by 90 days after HCT. Conditioning for HCT with as little as 35 mg/kg of BU provides minimal peritransplant mortality, rapid and sustained establishment of donor lymphohematopoiesis, replacement of lysosomal hydrolase, and prolonged survival in this murine model of human sphingolipidosis.     

New ion-implantation method for 4-µm period bubble device

It is well-known that bubble propagation margins for ion-implanted bubble devices depend strongly on ion-implantation conditions. A new ion-implantation method is reported that can significantly improve bubble propagation margins for minor loops with 4 × 4 μm bit cell size. The implantation was done through a Mo thin film layer so that the lattice strain and the anisotropy field change would be more uniform through the depth of the implanted layer. With this method, minor loops can be formed by hydrogen single implantation. Consequently simplification of the implantation process is achieved.     

Mn SOD activity and protein in a patient with chromosome 6-linked autosomal recessive parkinsonism in comparison with Parkinson's disease and control

We report Mn superoxide dismutase (SOD) protein and activity in a patient with familial autosomal recessive Lewy body-negative parkinsonism in comparison with patients with sporadic Parkinson's disease (PD) and controls. We recently proved linkage of this family with markers of chromosome 6 at 6q25.2-27, which included the Mn SOD gene. We used a novel polymorphic mutation at -9 position of the signal peptide of the Mn SOD precursor protein, which caused valine to alanine substitution. All the affected members of this family showed homozygosity for alanine, whereas nonaffected members, sporadic PD patients, and the control subjects studied showed either heterozygosity of alanine and valine or homozygosity of valine. The Mn SOD activity of this familial patient was the highest among the PD patients and the control subjects studied, and an abundant expression of Mn SOD was found in the substantia nigra. The molecular weight of Mn SOD protein by Western blotting of this patient was essentially similar to that of PD patients and the control subjects. High Mn SOD activity may constitute a genetic risk factor in this familial patient. The difference in the signal peptide sequence may affect the expression of Mn SOD within mitochondria; however, it is unlikely that loss of function type Mn SOD mutation is the cause of this familial parkinsonism. Mn SOD in sporadic PD patients was similar to that in controls.     

High-performance genetic analysis on microfabricated capillary array electrophoresis plastic chips fabricated by injection molding

We have developed a novel technique for mass production of microfabricated capillary array electrophoresis (mu-CAE) plastic chips for high-speed, high-throughput genetic analysis. The mu-CAE chips, containing 10 individual separation channels of 50-microm width, 50-microm depth, and a 100-microm lane-to-lane spacing at the detection region and a sacrificial channel network, were fabricated on a poly(methyl methacrylate) substrate by injection molding and then bonded manually using a pressure-sensitive sealing tape within several seconds at room temperature. The conditions for injection molding and bonding were carefully characterized to yield mu-CAE chips with well-defined channel and injection structures. A CCD camera equipped with an image intensifier was used to monitor simultaneously the separation in a 10-channel array with laser-induced fluorescence detection. High-performance electrophoretic separations of phiX174 HaeIII DNA restriction fragments and PCR products related to the human beta-globin gene and SP-B gene (the surfactant protein B) have been demonstrated on mu-CAE plastic chips using a methylcellulose sieving matrix in individual channels. The current work demonstrated greatly simplified the fabrication process as well as a detection scheme for mu-CAE chips and will bring the low-cost mass production and application of mu-CAE plastic chips for genetic analysis.     

1.5 μm transmission experiment with distributed feedback laser

The paper reports an experiment which demonstrates the possibility of error-free transmission over 100 km without repeater, by using a single-mode fiber and a laser diode with distributed feedback emitting a single longitudinal mode at the wavelength 1.5 μm.