Million Cells

Abstract: The total numbers of neurons and glial and endothelial cells in five rat spinal cords were estimated by stereological techniques. Each spinal cord was divided into 12 slabs of equal length. One transverse and one oblique slice was cut from each slab. The volumes of gray and white matter of each cord were then estimated by point-counting techniques on the transverse slices. By means of optical disectors and systematic sampling, the numerical densities of different cell types were estimated on 35 microns-thick plastic sections from the oblique slices. The total cell number was calculated by multiplying the numerical density by the total volume of gray and white matter. On average there were 15.1 and 21.1 million cells in white and gray matter, respectively. Of the cells in gray matter, 6.4 million were judged to be neurons, 4.3 million to be endothelial, and 10.3 million to be glial. Of the neurons, 1.7 million were located in the cervical region, 2.5 million in the thoracic, 1.6 million in the lumbar, and 0.6 million in the sacro-coccygeal region. The methods used are simple to perform, and the counting necessary to obtain a reliable estimate of cell number from one spinal cord can be carried out during the course of 1 day. The only major problem is reliable criteria for unambiguous cell classification.

Abstract: Corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) are expressed in cells of the immune system where they exert immunomodulatory roles, but these neuropeptides are poorly characterized in human immune tissues. The aim of this study was to determine concentrations and distribution of CRH and AVP in nonactivated human peripheral blood mononuclear cells (PBMC). PBMC from normal human subjects were separated into enriched subpopulations of T and B cells and monocytes/macrophages by a magnetic bead/monoclonal antibody technique. CRH and AVP were measured in cell extracts by radioimmunoassay (RIA). CRH-immunoreactivity (ir) ranged 0.24–0.8 fmol/million cells (n = 6 subjects) in T cell extracts, 0.4–2.7 fmol/million cells (n = 4) in B cells and 0.63–2.16 fmol/million cells (n = 4) in macrophages. AVP-ir ranged 0.2–0.95 fmol/million cells in T cell extracts, <0.1–0.8 fmol/million cells in B cells and 0.14–3.19 fmol/million cells in macrophages. Reversed-phase high-performance liquid chromatography (HPLC) of T and B cell extracts revealed a peak of CRH-ir which coeluted with synthetic CRH-41; this peak was not present in macrophages. A second peak of CRH-ir which eluted in a more hydrophobic position was observed in extracts of T and B cells and macrophages. This unidentified form of CRH-ir is the predominant form of CRH-ir in nonactivated human PBMC. This is the first study to demonstrate that CRH-ir and AVP-ir are colocalized within human T cells, B cells and monocytes/macrophages. We have confirmed observations of a variant form of CRH-ir in human PBMC and show that this is the predominant form in macrophages and B cells whereas CRH-ir, which coelutes with CRH(1–41) on HPLC, is present in significant amounts only in T cells. These data also confirm that CRH-ir in human PBMC is not urocortin because the antiserum used in the CRH RIA does not bind to urocortin.

Abstract: PBSCs are usually mobilized using G-CSF with or without chemotherapy. With the emergence of newer mobilizing agents, predicting poor mobilization may allow early intervention and prevent the costs and complications associated with remobilization. We retrospectively evaluated a cohort of 1556 patients seen between January 2000 and September 2008 with multiple myeloma (565; 36%), non-Hodgkin's lymphoma (NHL) (562; 36%), amyloidosis (345; 22%) or Hodgkin's disease (94; 6%), who were initially mobilized with single agent G-CSF. Sensitivity and specificity analysis was used to identify ideal peripheral blood CD34 count (PB-CD34) cutoff points that predicted successful collection. In patients with plasma cell disorders, a PB-CD34 count of 11, 17, 21 and 28/μL by day 4 or 5 was required to collect a target of 2, 4, 8 or 12 million cells/kg, respectively. A CD34 yield of <0.8 million cells/kg on first apheresis also predicted for <2 million CD34 cells/kg. For patients with NHL or Hodgkin's disease, a PB-CD34 count of <6 and <15/μL on day 4 or 5 predicted failure to achieve a target collection of 2 and 4 million cells/kg, respectively. This study suggests that PB-CD34 thresholds should be based on collection target to allow for early intervention and to prevent collection failures.