Biomedical subjects

E Rodger

Publications and source records attributed to E Rodger.

7 recordsLinked to original sources

PubMed2002

Craniosynostosis.

Craniosynostosis, caused by premature fusion of the sutures, may be syndromic or non-syndromic. Radiology has an important role to play in the assessment, management and follow-up of these patients. Initial investigations may often be undertaken within general radiology departments. An understanding of the terminology and recognition of the predictable patterns of presentation are essential to enable appropriate referral to a craniofacial unit where further investigation and management are undertaken. We present the radiological features of several craniosynostoses with an emphasis on the role of plain radiography. We demonstrate the complementary role of computed tomography in their evaluation within the setting of a specialist centre.

Craniosynostoses↗

PubMed2001

Impaired survival of bone marrow hematopoietic progenitor cells in cyclic neutropenia.

Cyclic neutropenia (CN) is a congenital hematopoietic disorder characterized by remarkably regular oscillations of blood neutrophils from near normal to extremely low levels at 21-day intervals. Recurring episodes of severe neutropenia lead to repetitive and sometimes life-threatening infections. To investigate the cellular mechanism of CN, the ultrastructure and the proliferative and survival characteristics of bone marrow-derived CD34(+) early progenitors, CD33(+)/CD34(-) myeloid progenitors, and CD15(+) neutrophil precursors from CN patients and healthy volunteers were studied. The ultrastructural studies showed profound apoptotic features in bone marrow progenitor cells in CN. Colony-forming assays demonstrated a 75% decrease in the number of early myeloid-committed colonies compared with controls. Long-term culture-initiating cell assays demonstrated a 6-fold increase in production of primitive progenitor cells in CN. To determine whether accelerated apoptosis might account for the underproduction of myeloid progenitors, the hematopoietic subpopulations were labeled with fluorescein isothiocyanate-annexin V and analyzed by flow cytometry. Short-term culture of CN cells resulted in apoptosis of approximately 65% of CD34(+) cells, 80% of CD33(+)/CD34(-) cells, and more than 70% of CD15(+) cells, as compared with 20%, 7%, and 15% apoptosis in respective control subpopulations. Evidence of accelerated apoptosis of bone marrow progenitor cells was observed in all 8 patients participating in the study, regardless of the stage in the CN cycle in which bone marrow aspirations were obtained. Granulocyte colony-stimulating factor therapy of CN patients significantly improved survival of bone marrow progenitor cells. These data indicate that ineffective production of neutrophils is due to accelerated apoptosis of bone marrow myeloid progenitor cells in CN.

Annexin A5↗

PubMed2000

Combined administration of G-CSF and dexamethasone for the mobilization of granulocytes in normal donors: optimization of dosing.

BACKGROUND: The clinical utility of neutrophil (polymorphonuclear leukocyte, PMN) transfusion therapy has been compromised, in part, by the inability to obtain sufficient quantities of functional neutrophils from donors. Mobilization of PMNs in the peripheral blood of normal volunteers has been shown to be superior when G-CSF is administered in conjunction with dexamethasone to that when either agent is administered alone. The current study was conducted to determine the optimal dosages of G-CSF and dexamethasone to be administered to donors in a granulocyte transfusion program. STUDY DESIGN AND METHODS: Five normal subjects were randomly assigned to each of the following single-dose regimens over five consecutive weeks: 1) subcutaneous (SC) G-CSF at 600 microg and oral (PO) dexamethasone at 8 mg; 2) SC G-CSF at 450 microg and PO dexamethasone at 8 mg; 3) SC G-CSF at 450 microg and PO dexamethasone at 12 mg; 4) SC G-CSF at 450 microg; and 5) PO dexamethasone at 12 mg. Venous blood was collected at 0, 6, 12, and 24 hours after drug administration for determination of absolute neutrophil count (ANC). Side effects of drug administration were recorded by using a standardized symptom questionnaire. RESULTS: Maximal ANC was achieved at 12 hours after administration of drugs under each regimen. All four regimens containing G-CSF caused greater than 10-fold increases in the ANC. When administered in conjunction with dexamethasone, G-CSF resulted in statistically similar PMN mobilization at dosages of 450 microg and 600 microg. The combined single-dose regimen of SC G-CSF at 450 microg and PO dexamethasone at 8 mg increased the mean ANC from a baseline value of 2800 per microL to 37,900 per microL at 12 hours after administration. This regimen was well tolerated by the normal volunteers. CONCLUSION: In a single-dose format designed for clinical granulocyte transfusion programs, optimal PMN mobilization can be achieved in normal donors with a combined regimen of SC G-CSF at 450 microg, and PO dexamethasone at 8 microg.

Administration, Oral↗

PubMed1999

General practice. Variations enigma.

A study of general practice involving 23 health authorities and 2,270 practices completed last year, revealed considerable variations across England and Wales. Single-handed practices account for an average of 29 per cent of all those in the study. The majority of HAs had no practices linked to NHSnet. More than half the practices offered early morning surgeries, and many also offered appointments after six o'clock.

Benchmarking↗

PubMed1998

Neutrophil transfusions: kinetics and functions of neutrophils mobilized with granulocyte-colony-stimulating factor and dexamethasone.

BACKGROUND: The collection of adequate numbers of neutrophils (polymorphonuclear leukocytes, PMNs) from normal donors has long hampered the development of neutrophil transfusion therapy. The stimulation of donors with granulocyte-colony-stimulating factor (G-CSF) plus dexamethasone is a promising way of improving PMN collections. STUDY DESIGN AND METHODS: Sixteen normal subjects received G-CSF (600 micrograms subcutaneously) and dexamethasone (8 mg by mouth) 12 hours before leukapheresis. Measurements included PMN morphology, immunophenotype analysis, chemiluminescence, bactericidal activity, in vivo kinetics, and adverse effects. RESULTS: A mean of 77.4 +/- 6.4 x 10(9) PMNs was collected with each leukapheresis; 14 percent were bands. PMNs had increased surface expression of CD11b, CD18, CD14, CD32, and CD64. Bactericidal capacity against Staphylococcus aureus was normal. Inducible respiratory burst was maintained, although the responses to some agonists were diminished. Returned leukapheresis cells labeled with 3H-diisopropylfluorophosphate had a modestly decreased percentage of recovery and circulated with a prolonged half-life. Migration of these cells to skin chambers was approximately equal to that of the subjects' own blood PMNs. Adverse effects included transient bone pain, headache, hunger, and insomnia. CONCLUSIONS: Precollection treatment of leukapheresis donors with G-CSF plus dexamethasone is an effective way to enhance the collection of PMNs with normal or near-normal functional properties for PMN transfusion therapy.

Adult↗

PubMed1995

Long-term treatment of canine cyclic hematopoiesis with recombinant canine stem cell factor.

Grey collie dogs have cyclic fluctuations in their blood cell counts caused by a regulatory defect of hematopoietic stem cells. To examine the role of stem cell factor (SCF) or its receptor in this disorder, we investigated the stimulatory effects of recombinant canine SCF (rc-SCF) on in vitro marrow cultures, cloned and sequenced the grey collie SCF gene, and treated three grey collies with rc-SCF, either alone or in combination with recombinant canine granulocyte colony-stimulating factor (rcG-CSF). Colony-forming unit granulocyte-macrophage formation from grey collie or normal dog marrow showed similar dose-response curves for rc-SCF. Cloning and sequencing the SCF gene for two grey collies showed no evidence of mutations in the coding region of the SCF gene. Treatment with rc-SCF (10 to 100 micrograms/kg/d) did not induce neutrophilia except at the highest dose (100 micrograms/kg/d), but daily rc-SCF abrogated the neutropenic periods in doses of 20 micrograms/kg/d or greater. Combination of rc-G-CSF (0.5 to 1.0 microgram/kg/d) with rc-SCF treatment (20 to 50 micrograms/kg/d) suggested a synergistic effect, ie, the neutrophil levels on combined therapy were higher than the sum of the levels when these two cytokines were given separately. Long-term treatment of these dogs with rc-SCF in doses of 10 to 30 micrograms/kg/d was generally well tolerated, suggesting that SCF may be useful as a therapy for some chronic hypoproliferative disorders of hematopoiesis.

Animals↗

PubMed1993

Hematopoietic progenitors and aging: alterations in granulocytic precursors and responsiveness to recombinant human G-CSF, GM-CSF, and IL-3.

BACKGROUND: Changes either in the number or in the responsiveness of hematopoietic progenitors may be a major factor accounting for age-related changes in stimulus driven hematopoiesis. METHODS: To test these hypotheses, we compared the relative proportions and the responsiveness of CD34+ bone marrow cells from healthy young (20-30 yrs) and healthy elderly (70-80 yrs) volunteers to G-CSF, GM-CSF, and IL-3 in an in vitro marrow culture system. RESULTS: There was no age-related difference either in the proportion of CD34+ marrow cells or in the proportion of a more mature CD34+ subset, defined as CD34+, CD33+ cells. Maximal colony formation by CD34+ cells stimulated with a combination of G-CSF, GM-CSF, and IL-3 was similar in the two groups, but the dose-response studies with individual growth factors revealed a 2-fold decrease in sensitivity of the elderly subjects' cells to G-CSF (p < .01). CONCLUSIONS: Aging has little impact on the marrow content of early precursors of the neutrophil lineage. There is, however, a significant difference in the in vitro proliferative response of these cells to the lineage specific growth factor G-CSF. This alteration may account for the greater propensity in elderly populations for the development of neutropenia with severe infections and chemotherapy.

Adult↗