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Biomedical subjects

P Hollands

Publications and source records attributed to P Hollands.

10 recordsLinked to original sources
PubMed1999

The xenotransplantation of goat and human hematopoietic cells to sheep fetuses.

Hematopoietic xenografts were carried out in three experiments using goat fetal liver (44-48 days, experiments I and II) or purified human CD 34+ cells (experiment III) as the donor cells. Recipients were sheep fetuses at 41-47 days of gestation. Goat fetal liver cells were either injected without any pretreatment or stimulated by preincubation in a culturing in goat phytohemagglutinin-stimulated lymphocyte supernatant. Human CD 34+ myeloid progenitor cells were purified from bone marrow by minimacs immunomagnetic purification and cultured in medium supplemented with stem cell factor, IL3, and IL6. Goat-sheep chimerism was assessed by flow cytometry analysis (FCA) of peripheral blood and bone marrow cells using a mouse anti-goat CD 45 monoclonal antibody and by karyotype analysis of peripheral blood from goat/sheep chimeras. Human cell engraftment was assessed by polymerase chain reaction amplification of the human DAX1 gene in blood and bone marrow DNA from sheep which had received human cells. In the three experiments, a mean of 76% (26 of 34) of injected fetuses were born alive without any clinical evidence of graft-versus-host disease. Three lambs were found to be goat/sheep chimeric after flow cytometry analysis (peripheral blood and bone marrow) and karyotype (peripheral blood) analysis. Both tissues continued to express goat cells at 6 or 12 months (last assessment) depending on the experiment. No human chimerism was detected using polymerase chain reaction amplification in peripheral blood and bone marrow of any of the six sheep grafted with human cells. These data and those also obtained on other species (human, pig/sheep) show that it is possible to carry out hematopoietic xenografts using the sheep fetus as recipient provided both donor and recipient fetal cells are processed during the period of tolerance to foreign antigens.

Aging↗
PubMed1997

Comparative stem cell biology.

This review collates data from a range of stem cells studies in an attempt to bring together an overall view of stem cell biology. Data from hemopoietic, keratopoietic, hepatopoietic and neuropoietic stem cells are presented. The developmental and cell biology of each system is discussed in an attempt to develop a comparative view of stem cell biology. Comparisons are drawn in the areas of clonal analysis, surface antigen expression, adhesion molecules and cytokine interactions. Where appropriate the role of embryonic stem (ES) cells is also considered in the developmental biology of the cells in question.

Animals↗
PubMed1991

Embryonic stem cell grafting: the therapy of the future?

The grafting of mouse embryonic haemopoietic cells into deficient recipients is discussed. Donor cells can be obtained from post-implantation mouse embryos in vivo and used to treat X-irradiated or genetically anaemic recipients. The concept of grafting embryonic haemopoietic cells into normal, untreated recipients is also described. Preimplantation mouse blastocysts grown in vitro for 3-4 days can also be used as a source of donor cells. The haematological and immunological aspects of embryonic cell grafting are discussed, followed by a description of current xenotransplantation experiments, including rat into mouse and human into mouse. The review concludes with a discussion of the application of embryonic cell grafting to other tissues and a look into the possible future of this technique.

Anemia↗
PubMed1989

The use of Albuminar 5 as a medium supplement in clinical IVF.

Human serum and Albuminar 5 (A5) were compared as medium supplements to Earle's solution containing pyruvate in clinical IVF. One-hundred patients in each group showed a fertilization rate of 60% with serum and of 62% with A5. The overall pregnancy rates in the serum and A5 groups were 20 and 24%, respectively. The incidence of failed fertilization (6-7%) and of multipronucleate oocytes (4-5%) was similar in both groups. At 37 degrees C, sperm survived less well in A5 although the rate of fertilization was not reduced. Blastocyst formation was not seen in 'spare' embryos grown in vitro in medium containing 15% v/v A5.

Caprylates↗
PubMed1988

New advances in human embryology: implications of the preimplantation diagnosis of genetic disease.

The diagnosis of genetic disease in preimplantation embryos is discussed. The typing of spermatozoa may be feasible for factors such as the presence of an X and Y chromosome. Embryos might be typed by non-invasive methods, by assessing their uptake of metabolites although the widest opportunities may arise by the use of invasive methods which involve the removal of one or a small number of cells. The methods of diagnosis are discussed, including enzyme assays and the use of DNA probes, preliminary results with human embryos are presented and the difficulties related to these techniques are debated. The low rate of implantation of replaced embryos will mean that many embryos will have to be diagnosed, and certain embryological factors such as the high incidence of chromosomal imbalance and the problems of 'imprinting' might obscure certain diagnoses. The advantages and disadvantages of the method are discussed.

Embryo Implantation↗
PubMed1988

Transplantation of embryonic haemopoietic stem cells without prior recipient X-irradiation.

Allogeneic day 7 mouse embryonic cells can colonize the haemopoietic system of normal, non-irradiated recipient mice. Donor embryonic cells are disaggregated and injected intravenously resulting in colonization in 40% of recipients, as shown by the presence of electrophoretic markers, characteristic of the donor cells. Donor type haemoglobin (Hb) and donor type glucose phosphate isomerase (GPI) demonstrates the presence of donor type erythrocytes and lymphocytes respectively. Repeat grafts in recipients not showing donor makers did not result in colonization. Recipient type haemopoiesis was dominant in all types of recipient. Skin grafts of allogenic donor type skin onto successfully grafted embryonic cell recipients did not survive. Allogeneic donor embryonic cells therefore survive in recipients where adult skin allografts do not. Donor embryonic cells, homozygous for T6 marker chromosomes, were used to assess the site of colonization of intravenously grafted cells. Donor chromosomes were seen in recipient liver and bone marrow at low levels. This distribution of donor cells persists for up to 64 d post-graft.

Animals↗
PubMed1988

Embryonic haemopoietic stem cell grafts in the treatment of murine genetic anaemia.

Embryonic haemopoietic stem cells obtained from early post-implantation mouse embryos can be successfully used in the treatment of murine genetic anaemia. Anaemic recipients had either chronic macrocytic anaemia, which was lethal without treatment, or mild anaemia without increased mortality. All successfully grafted recipients developed donor haemoglobin and glucose phosphate isomerase electrophoretic markers, indicating the presence of donor erythrocytes and lymphocytes. The minimum number of embryonic cells resulting in a successful graft in chronic macrocytic anaemia recipients was 0.8 x 10(6) nucleated cells. Athymic (nude) mice were also colonized by embryonic haemopoietic stem cells. Donor electrophoretic markers were seen but all recipients soon died, possibly of pneumonia. Bone marrow grafts into recipients with chronic macrocytic anaemia were not successful. Bone marrow grafts into recipients with mild anaemia resulted in some recipients showing donor markers. These recipients later died, showing symptoms of graft-versus-host disease.

Anemia↗
PubMed1988

Differentiation of embryonic haemopoietic stem cells from mouse blastocysts grown in vitro.

Embryonic haemopoietic stem cells can differentiate from mouse blastocysts grown in vitro. Mouse blastocysts were cultured for 3 or 4 days and the resultant cells were injected intravenously into lethally X-irradiated or genetically anaemic recipient mice. Blastocysts grown in vitro did not maintain normal embryonic morphology. The presence of donor haemoglobin and donor lymphocytic glucose phosphate isomerase in grafted recipients, demonstrates the presence of embryonic haemopoietic stem cells. Recipients of embryonic haemopoietic stem cells, obtained from growth in vitro, were haematologically stable with no evidence of neoplasia. Pluripotent embryonic cells, maintained on fibroblast feeder layers, were unable to colonize X-irradiated or genetically anaemic mice. Recipients of pluripotent cells died at the same time as saline-injected controls.

Anemia↗
PubMed1987

Differentiation and grafting of haemopoietic stem cells from early postimplantation mouse embryos.

Haemopoietic stem cells evidently arise in early post-implantation mouse embryos at day 6 of gestation, a day earlier than previously thought (Moore & Metcalf, 1970). Disaggregated embryonic cells were injected into mice given a lethal dose of X-irradiation. The presence of donor haemoglobin (Whitney, 1978) and donor lymphocytic glucose phosphate isomerase (GPI) (Siciliano & Shaw, 1976) to detect donor erythrocytes and lymphocytes, respectively, were monitored by starch gel electrophoresis. The presence of donor cells was also assessed by using donor embryos carrying the T6 marker chromosomes. Decidual cells dissected free of embryos did not colonize any recipients. Disaggregated cells from early mouse embryos first colonized the liver and then repopulated the haemopoietic systems of recipients, producing adult donor haemoglobin within 2-3 days and donor GPI within 3-5 days. 80% of grafted X-irradiated recipients survived and donor markers were found in each of them. All nongrafted controls died within 14 days of X-irradiation and none of them showed donor markers. Disaggregated embryonic cells could be grafted across major histocompatibility barriers unlike adult bone marrow. Haemopoietic stem cells could not be identified in disaggregated cells from embryos aged less than 6 days gestation.

Animals↗