PubMed Health⌕ Search

Biomedical subjects

A J Emmerson

Publications and source records attributed to A J Emmerson.

16 recordsLinked to original sources
PubMed2003

Tibial speed of sound in term and preterm infants.

The tibial speed of sound (SOS) was measured in 91 healthy singleton infants between 31 and 42 weeks of gestation and 12 sick preterm infants. In healthy infants, the tibial SOS was associated with corrected gestational age (r = 0.40, p < 0.001) but not birth weight. The median tibial SOS in 12 sick preterm infants (2,772, range 2,566-2,934 m/s), whose corrected gestational age was between 31 and 42 weeks, was lower (p < 0.001) than that of 69 healthy gestation-matched healthy infants (3,100, range 2,870-3,381 m/s). Tibial SOS measurements may allow radiation-free assessment of metabolic bone disease of prematurity.

Birth Weight↗
PubMed2003

Parenteral nutrition solution retrieved by lumbar puncture following left saphenous vein catheterization.

Two extremely preterm infants had silastic lines inserted via the left great saphenous vein for intravenous feeding. Clinical deterioration approximately 10 days later led to lumbar puncture as part of a sepsis screen. Parenteral nutrition solution was recovered in the cerebrospinal fluid and heralded potentially life-threatening catheter malposition. The cases illustrate another percutaneous central line-associated morbidity, which is avoidable by careful verification of line position. All previously reported cases of this unusual complication are reviewed and we describe its likely mechanism. We postulate that the phenomenon is a complication peculiar to percutaneous catheterization of the left lower limb.

Australia↗
PubMed2001

A trial of recombinant human granulocyte colony stimulating factor for the treatment of very low birthweight infants with presumed sepsis and neutropenia.

OBJECTIVES: The primary objective was to investigate the safety of recombinant human granulocyte colony stimulating factor (rhG-CSF) for the treatment of very low birthweight infants (VLBW) with sepsis and relative neutropenia, specifically with regard to worsening of respiratory distress and thrombocytopenia and all cause mortality. Secondary objectives were to evaluate duration of ventilation, intensive care, and antibiotic use as markers of efficacy. DESIGN: Neonates (< or = 28 days) in intensive care, with birth weights of 500-1500 g, absolute neutrophil count (ANC) of < or = 5 x 10(9)/l, and clinical evidence of sepsis, were randomly assigned to receive either rhG-CSF (10 microg/kg/day) administered intravenously (n = 13), or placebo (n = 15) for a maximum of 14 days, in addition to standard treatment and antibiotics. All adverse events, oxygenation index, incidence of thrombocytopenia, all cause mortality, duration of ventilation, intensive care and antibiotic treatment, and ANC recovery were compared between the two groups. RESULTS: Adverse events and oxygenation index were not increased by, and thrombocytopenia was not attributable to, treatment with rhG-CSF. At 6 and 12 months postmenstrual age, there were significantly fewer deaths in the group receiving rhG-CSF (1/13 v 7/15; p < or = 0.038). There was a non-significant trend towards a reduction in duration of ventilation, intensive care, and antibiotic use in the rhG-CSF group. There was a significantly more rapid increase in ANC in the rhG-CSF treated babies (p < 0.001). CONCLUSIONS: In a small randomised placebo controlled trial in a highly selected group of neonates, adjuvant treatment with rhG-CSF increased ANC rapidly, and no treatment related adverse events were identified. Mortality at 6 and 12 months postmenstrual age was significantly lower in the treatment group. A large trial investigating efficacy in a similar group of neonates is warranted.

Anti-Infective Agents↗
PubMed1994

The in vitro effects of stem cell factor, interleukin 3 and granulocyte-macrophage colony stimulating factor on haemopoietic progenitor cells from premature infants.

Circulating haemopoietic progenitor cells from premature infants were assessed for their ability to respond to interleukin 3, granulocyte-macrophage colony stimulating factor and stem cell factor (SCF) in vitro. All three cytokines increased the number of colonies derived from burst forming units erythroid (BFU-E), colony forming units granulocyte-macrophage (CFU-GM) and multi-lineage progenitors (CFU-Mix) grown in the presence of erythropoietin (Epo). The size and haemoglobin content of BFU-E derived colonies also increased in the presence of the cytokines. Of those tested, SCF was found to be the most potent additive to Epo for the enhanced growth of BFU-E and CFU-Mix. In short-term liquid cultures without Epo, SCF alone induced globin synthesizing cells. Progenitors from premature infants were at least as responsive to all three cytokines as those from healthy adults. The use of SCF in combination with Epo in the prevention or treatment of anaemia in premature infants warrants further investigation.

Cells, Cultured↗
PubMed1993

Double blind trial of recombinant human erythropoietin in preterm infants.

Twenty four infants between 27 and 33 weeks' gestation were recruited into a double blind study to investigate the use of recombinant human erythropoietin (r-HuEpo) for the prevention of anaemia of prematurity. Between 50 and 150 U of r-HuEpo (n = 16) or placebo was administered subcutaneously twice a week from 7 days of age until discharge. There was a significant increase in the reticulocyte count in infants receiving r-HuEpo sustained from the second week of treatment until discharge compared with placebo. There was a reduction in the number of transfusions required in the r-HuEpo group with only 47% requiring a transfusion compared with 87% in the placebo group. During treatment with r-HuEpo there was a significant rise in the red cell folate concentration, a significant fall in the ferritin concentration, and a significantly higher percentage of haemoglobin F at discharge suggesting active erythropoiesis. The study provides strong evidence for the efficacy of r-HuEpo in stimulating erythropoiesis and reducing the requirement for transfusions for anaemia of prematurity.

Anemia, Neonatal↗
PubMed1992

The in vitro effect of high-dose recombinant human erythropoietin on granulocyte-macrophage colony production in premature infants using a defined serum deprived cell culture system.

Recent reports of neutropenia associated with the use of recombinant human erythropoietin (r-HuEpo) in preterm infants with the anaemia of prematurity have raised concern over the clinical use of this hormone. The present studies were undertaken to determine whether high-dose r-HuEpo has an effect on granulocyte production in vitro. The studies used a serum deprived, optimized semi-solid cell culture system to investigate the effect of lineage specific and non-specific granulocyte and erythroid colony stimulating factors on circulating peripheral blood granulocyte-macrophage colony forming units (CFU-GM), erythroid burst forming units (BFU-E) and multilineage colonies (CFU-Mix) from nine premature infants and seven healthy adults. CFU-GM were grown in the presence of interleukin 3 (IL3) 8 ng/ml, granulocyte-macrophage colony stimulating factor (GM-CSF) 20 ng/ml and granulocyte colony stimulating factor (G-CSF) 15 ng/ml alone and combinations of G-CSF with GM-CSF or IL3. The number, size and differentiation of CFU-GM colonies were then analysed in the presence and absence of high dose r-HuEpo (4 U/ml). High-dose r-HuEpo did not exert any significant modulatory effects on the number of CFU-GM colonies produced in the presence of IL3, GM-CSF and G-CSF alone or in combination. The number of cells within each CFU-GM colony did not change significantly, nor was there a significant change in the degree of differentiation. The combined number of BFU-E, CFU-GM and CFU-Mix colonies increased with r-HuEpo in both adults (1.8 x) and preterm infants (1.4 x), almost exclusively due to an increase in BFU-E derived colonies. Thus, no evidence was found for an r-HuEpo mediated redirection of multipotential haemopoietic stem cells into committed erythroid precursors at the expense of myeloid precursors.

Cell Differentiation↗
PubMed1991

Erythropoietic progenitor cells from premature neonates studied using a validated serum-deprived medium. Evidence that peripheral blood BFU-E from premature neonates are increased in number and are highly dependent upon burst promoting activity for in vitro growth.

We have examined a serum-deprived culture system in order to verify that it is suitable for the study of burst forming unit erythroid (BFU-E) progenitor cells from premature neonates. Optimum growth of BFU-E from premature neonates was observed with each media constituent using the same concentration as that previously described for adult subjects. Growth of immature BFU-E from premature neonates were highly dependent upon a source of Burst Promoting Activity and mature BFU-E derived colonies emerged at day 12 compared to day 14 in adults. Our preliminary results with the validated medium suggest that premature infants have increased peripheral blood concentrations of BFU-E compared to healthy adult controls.

Adult↗
PubMed1991

Erythropoietin responsive progenitors in anaemia of prematurity.

Circulating erythroid progenitors (BFU-E) in five anaemic preterm infants (haemoglobin less than 100 g/l) were about 2 and 4.4 times as abundant as in 10 preterm infants who were not anaemic and five healthy adults, respectively, and were significantly more responsive to low concentrations of recombinant human erythropoietin (rHuEpo) than those from healthy adults. These results encourage further studies in the use of rHuEpo for the treatment of the anaemia of prematurity.

Adult↗
PubMed1989

Anterior abdominal wall defects.

A total of 48 infants with abdominal wall defects referred to the South West Regional Neonatal Surgical Centre over a period of six years were reviewed. There were 27 (56%) infants with gastroschisis and 21 (44%) infants with exomphalos. At the regional centre, four pregnancies with gastroschisis were terminated following a prenatal diagnosis, one child was stillborn, and one with exomphalos and trisomy 13 died soon after birth. Of the remaining 42 live births, the one year survival for babies born with a gastroschisis was 95% (21/22) and with an exomphalos was 81% (17/20). All deaths, except one, were due to factors other than the abdominal defect. The effect on outcome of prenatal diagnosis, parental counselling, in utero transfer, mode of delivery, and methods of surgical closure was reviewed.

Abdominal Muscles↗
PubMed1988

Height at diagnosis in diabetes.

There was no significant difference in the heights of 66 insulin-dependent diabetic children at diagnosis when compared with age, sex and period-matched controls.

Adolescent↗
PubMedDate not supplied

Properties of peripheral blood and cord blood stem cells.

Mobilized peripheral blood and cord blood are used for transplantation in adults and children. Currently methods which assess the engraftment potential of these cells rely on nucleated cell count, clonogenic colony assays (GM-CFC) and CD34+ cell enumeration. However, data have accumulated which indicate that the cells responsible for short-term and long-term engraftment are different and may be identified by a variety of techniques, including immunophenotyping, in vitro and in vivo assays. There is also evidence that primitive cells in peripheral blood progenitor cell grafts and cord blood are heterogeneous, as cells with similar functional behaviour express different phenotypes. Despite intensive research, the isolation and identification of a homogeneous population of human stem cells is still elusive. Nevertheless, it is possible to obtain CD34+ subpopulations enriched in primitive cells with many of the properties expected of stem cells. Using these cell fractions, the cytokines that induce proliferation, amplification, differentiation and self-renewal are being defined in order to develop improved protocols for expansion of specific populations. From these studies a number of interesting facts have emerged. Certain growth factors frequently used for progenitor cell expansion and gene transduction studies also induce differentiation and impair long-term engraftment. Further, the cytokines required for progenitor cell expansion are probably different to those which favour expansion of the primitive cells, with both the cell cycle status of CD34+ cells as well as the implication of telomere shortening probably needing to be considered where ex vivo manipulation is contemplated.

Antigens, CD34↗