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Biomedical subjects

A E James

Publications and source records attributed to A E James.

At least 19 recordsLinked to original sources
PubMed2005

Multipotent neural precursors express neural and hematopoietic factors, and enhance ex vivo expansion of cord blood CD34+ cells, colony forming units and NOD/SCID-repopulating cells in contact and noncontact cultures.

In view of the possible crosstalks between hematopoiesis and neuropoiesis, we evaluated two microenvironments, murine neonatal neural cell line C17.2 and primary embryonic aorta-gonad-mesonephros (AGM) stromal cells, on the ex vivo expansion of CD34+ cells from human cord blood. In a contact culture system, C17.2 or AGM cells significantly enhanced the expansion of CD34+ cells to a panel of early and committed hematopoietic progenitor cells. In a noncontact transwell system, pre-established C17.2 cells significantly increased the expansion of total nucleated cells, CD34+ cells and multilineage colony forming cells (P<0.01). Expanded cells were infused into nonobese diabetic/severe-combined immunodeficient mice. The engraftment of human (hu)CD45+ cells in the bone marrow of these mice was consistently higher in all the 10 experiments conducted with the support of C17.2 cells when compared with those in respective control groups (11.9 vs 2.43%, P=0.03). Using RT-PCR and Southern blot analysis, we showed that AGM and C17.2 cells expressed a panel of hematopoietic, bone morphogenetic and neurotrophic factors. Our data provided the first evidence on the promoting effects of a neural progenitor cell line on hematopoiesis at a noncontact condition. The mechanism could be mediated by the expression of multilineage regulatory factors.

Animals↗
PubMed2002

Cobblestone area-forming cells, long-term culture-initiating cells and NOD/SCID repopulating cells in human neonatal blood: a comparison with umbilical cord blood.

Our prior study demonstrated that neonatal blood (NB) contained hematopoietic stem and progenitor cells that declined rapidly after birth. To validate that NB is a source of functional stem cells, we characterized this population in terms of cobblestone area-forming cells (CAFC), long-term culture-initiating cells (LTC-IC) and NOD/SCID mouse repopulating cells (SRC) in NB and umbilical cord blood (CB). Our data demonstrated that the frequencies of CAFC (30.2 vs 37.1, P = 0.14) and LTC-IC (28.6 vs 31.0, P = 0.49) in 1 x 10(5) mononuclear cells (MNC) of NB and CB were similar, suggesting that these cells were preserved in the circulation of the neonates shortly after birth. Sublethally irradiated NOD/SCID mice were transplanted with CD34(+) cells enriched from thawed NB and CB. At 6 weeks post transplant, human (hu)CD45(+) cells were detected in the bone marrow (BM), spleen and peripheral blood (PB) of the mice as demonstrated by flow cytometric and DNA analysis. Levels of huCD45(+)cells and colony forming units (CFU) appeared to be dependent on the infusion cell dose and were higher in animals receiving CB cells when compared with those of the NB group. The transplanted cells were capable of differentiation into multi-lineage progenitor cells (CD34(+) cells and differential CFU), as well as mature myeloid (CD14(+), CD33(+)), B lymphoid (CD19(+)) and megakaryocytic (CD61(+)) cells in the recipients. NB cells, subjected to ex vivo culture in an optimized preclinical condition, were significantly expanded to early and committed progenitor cells. Expanded NB contained SRC at a reduced quantity but with high proportions of CD14(+) cells and CD33(+) cells. Our study confirms that NB contains pluripotent hematopoietic stem and progenitor cells capable of homing and engrafting the NOD/SCID mice.

Animals↗
PubMed2001

Delivery and scavenging system for small animal inhalational anesthesia.

BACKGROUND: Inhalational agents have been widely used for anesthesia in laboratory animals. However, the safe use of inhalational agents in small laboratory animals has been limited by the lack of a suitable and effective scavenging system for the removal of waste anesthetic gases. The aim of the present study is to develop an anesthetic system that can be manufactured using common household and laboratory items. MATERIALS AND METHODS: An anesthetic system was designed for rats weighing from 300 to 350 g. A face mask for the rat was made by cutting off the distal part of a 50-ml centrifuge tube. A scavenging hood was made from a transparent plastic food storage box. Exhaust of anesthetic gases from the scavenger hood was facilitated by fitting an outlet connected to a pump. Four experienced researchers or technicians tested the scavenger hood. RESULTS: In 79.2% of the trials the participants could smell halothane when the pump from the scavenger system was not operational. However, when the pump was switched on, halothane was detected only 16.7% of the time (P < 0.001). CONCLUSION: We have developed a simple and effective method of delivering inhalational anesthesia to small laboratory animals and of removing waste anesthetic gases.

Anesthesia, Inhalation↗
PubMed2001

Preclinical ex vivo expansion of cord blood hematopoietic stem and progenitor cells: duration of culture; the media, serum supplements, and growth factors used; and engraftment in NOD/SCID mice.

BACKGROUND: Ex vivo expansion of cord blood (CB) hematopoietic stem and progenitor cells increases cell dose and may reduce the severity and duration of neutropenia and thrombocytopenia after transplantation. This study's purpose was to establish a clinically applicable culture system by investigating the use of cytokines, serum-free media, and autologous plasma for the expansion of CB cells and the engraftment of expanded product in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. STUDY DESIGN AND METHODS: Enriched CB CD34+ cells were cultured in four media (Iscove's modified Dulbecco's medium with FCS, Gibco; X-Vivo-10, BioWhittaker; QBSF-60, Quality Biological; and StemSpan SFEM, Stem Cell Technologies) with four cytokine combinations (thrombopoietin [TPO], SCF, Flt-3 ligand [FL] with and without G-CSF, and/or IL-6). The effect of autologous CB plasma was also investigated. The read-out measures were evaluated on Days 8 and 12. After expansion at the optimized condition, cultured cells were transplanted into sublethally irradiated NOD/SCID mice. The engraftment of human CD45+ cells and subsets in the bone marrow, spleen, and peripheral blood was determined. RESULTS: QBSF-60 or StemSpan SFEM supported high yields of early progenitors (CD34+ cells, <or= 64.8-fold; CD34+CD38- cells, 330-fold; CFU-granulocyte erythroid macrophage megakaryocyte [GEMM], 248-fold) and CFUs of the myeloid (CFU-GM, 407-fold) and erythroid (BFU/CFU-E, 144-fold) lineages. The expansion of the megakaryocytic lineage was consistently higher in X-Vivo-10 (CFU-megakaryocyte, 684-fold). Autologous plasma promoted colony formation but reduced CD34+ cells and CFU-GEMM. The addition of G-CSF or IL-6 improved cell yields; G-CSF was more effective for committed progenitors. Expansion products from cultures in QBSF-60 with the cytokines engrafted and differentiated into the myeloid and lymphoid lineages in NOD/SCID mice. CONCLUSION: The data supported the strategy of expansion. The optimized condition may be applicable to clinical expansion for the abrogation or reduction of posttransplant cytopenia.

Animals↗
PubMed1999

The effect of percutaneous oestradiol on atheroma formation in ovariectomized cholesterol-fed rabbits.

OBJECTIVE: The aim of this study was to examine the effect of percutaneous oestradiol on the lipid profile and on atheroma formation using an animal model. METHODS: The study was of 12 weeks duration. Fifty sexually mature female New Zealand White rabbits were divided into five groups of equal size. Two groups acted as controls and received normal rabbit chow. Rabbits in one of these groups were ovariectomized. The remaining three groups were ovariectomized but received 1% cholesterol enriched rabbit chow. One of these cholesterol-fed groups received 0.3 mg/kg percutaneous oestradiol daily whilst another received 0.1 mg/kg oral oestradiol daily. Measurements of concentrations of total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and triglycerides (TG) were made at the beginning and end of the study. Aortic atheroma formation was measured using computerized image analysis of uptake of Sudan III staining. RESULTS: After 12 weeks there were significant increases in the mean concentrations of TC in the three cholesterol-fed groups compared with controls (P < 0.001). Changes in HDL-C and TG concentrations were less consistent. The mean area of aortic atheroma formation was significantly less in both the percutaneous oestradiol group (4.9%) and the oral oestradiol group (8.6%) compared with the non-oestrogen-treated cholesterol-fed group (19.5%) (P < 0.001, < 0.01 respectively). CONCLUSION: These results suggest that percutaneous oestradiol has a direct protective effect on atheroma formation independent of serum concentrations of total cholesterol.

Administration, Oral↗
PubMed1997

A pilot study of the theoretical and technical competence and appropriate education for the use of nine physical agent modalities in occupational therapy practice.

OBJECTIVE: This study described occupational therapy practitioners' perceptions about the content and method of training or education necessary for gaining theoretical and technical competence in the use of nine physical agent modalities (PAMs). METHOD: A survey was developed and sent to 543 members of the Physical Disabilities Special Interest Section of the American Occupational Therapy Association who had identified their primary area of practice as hand therapy. One hundred and fifty-one completed surveys (28% response rate) were returned. RESULTS: The respondents indicated that theoretical and technical expertise necessary for competent use of PAMs varied according to the type of modality being considered. Continuing education courses were identified as the best method for gaining theoretical and technical competence for the use of deep thermal agents, such as ultrasound and electrical stimulation agents, whereas entry-level professional education and one-the-job training were identified as most appropriate for superficial thermal agents, such as paraffin bath and hot and cold packs. CONCLUSION: The results suggest that considerations regarding the type and amount of education necessary for gaining theoretical and technical competence in the use of PAMs depend on the type of modality being addressed. These differences should be considered in the future development of competency objectives for the use of PAMs.

Adult↗