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Biomedical subjects

E Morgan

Publications and source records attributed to E Morgan.

At least 37 records · Page 2Linked to original sources
PubMed1998

Outpatient total body irradiation prior to bone marrow transplantation in pediatric patients: a feasibility analysis.

Outpatient total body irradiation (TBI) prior to bone marrow transplantation has been accomplished in a total of 68 pediatric patients. The TBI regimen was fractionated with a total dose of 12 Gy in eight fractions twice daily. Antiemetic therapy consisted of oral ondansetron three times daily throughout the TBI course. Eight patients experienced mild nausea without vomiting, and four patients experienced mild nausea and vomiting. One patient required intravenous hydration after severe nausea and vomiting. Another patient experienced intractable diarrhea and dehydration which required inpatient management. Outpatient TBI prior to bone marrow transplantation is feasible in pediatric patients.

Adolescent↗
PubMed1998

Creating a framework for clinical nursing practice to advance in the West Midlands region.

The West Midlands Regional Health Authority identified a lack of opportunities for nurses to develop advanced clinical practice through a recognized programme at Postgraduate diploma/Masters degree level. Education for clinical practice must be equally grounded in theory and practice. Advanced clinical practice requires more than just skills acquisition, it has a much wider remit incorporating elements of clinical expertise and higher level decision making, research awareness, teaching and role modelling, informing policy making and leading in the provision of patient care within individual Trusts. This initiative has encouraged universities, trusts and provider units to work together to identify and prepare students and staff for their changes in role, and to review existing boundaries for practice which will enable new approaches to team work and the provision of holistic patient care.

Career Mobility↗
PubMed1998

Efficacy of autologous peripheral blood stem cell (PBSC) harvest and engraftment after ablative chemotherapy in pediatric patients.

Thirty-five pediatric patients, 1-16 years of age (median 6.3 years), with neoplastic solid tumors (n=32) or acute leukemia (n=3) underwent peripheral blood stem cell (PBSC) harvest and transplantation at Children's Memorial Hospital between September 1992 and April 1997. A median of four phereses were performed on each patient. Blood samples from 34 of the 35 patients were harvested through existing double-lumen central catheters, using either a Fenwal CS-3000 or COBE Spectra pheresis machine. The pheresis procedures were well tolerated overall. A median of 3.7 x 10(6)/kg CD34+ cells were infused (range, 0.2-15.5 x 10(6)/kg), and all patients engrafted. The median time to an absolute neutrophil count >500/microL was 13 days (range, 9-44 days) and to a platelet count >20,000/microL was 21 days (range, 9-210 days). Two patients died from transplant-related complications. Patients were discharged from the hospital after a median of 22 days (range, 15-64 days). Twenty of the 35 patients are alive, 17 of whom remain disease-free with a median follow-up of 1144 days. According to this study, PBSCs can be successfully harvested and re-infused for marrow reconstitution after myeloablative therapy in children for a variety of pediatric malignancies with low morbidity and mortality.

Acute Disease↗
PubMed1998

Mechanisms of ferric citrate uptake by human hepatoma cells.

The mechanisms of uptake of non-transferrin-bound iron by human hepatoma cells (HuH7) were investigated using 59Fe-citrate and [14C]citrate. The amount of iron associated with the cells increased linearly with time, whereas citrate uptake reached a plateau after 45 min, resulting in a cellular accumulation of iron over citrate. The cells displayed high-affinity membrane binding sites for citrate with maximum binding of 118 +/- 17 pmol citrate/mg protein and a dissociation constant of 21 +/- 2 microM (n = 3). Iron uptake was saturable with a maximum uptake rate of 1.95 +/- 0.43 pmol . mg protein-1 . min-1 and an apparent Michaelis constant of 1.1 +/- 0.1 microM. Nonradioactive ferric citrate and citrate inhibited 59Fe uptake to a similar degree. This suggests that the uptake of citrate-bound iron is dependent on either binding to specific citrate binding sites or the concentration of unbound iron. The uptake of iron was inhibited by ferricyanide (>100 microM) and ferrous iron chelators but stimulated by ferrocyanide and ascorbate, suggesting that the iron is reduced from Fe3+ to Fe2+ and transported into the cell by an iron carrier-mediated step.

2,2'-Dipyridyl↗
PubMed1998

Cardiac tamponade during laparoscopic Nissen fundoplication.

Laparoscopic Nissen fundoplication is becoming a popular technique in the surgical management of reflux disease. The advantages of laparoscopic surgery include shorter hospital stays, greater patient acceptance and decreased overall morbidity. Laparoscopic surgery eliminates the necessity for an upper abdominal incision and the consequent post-operative impairment of pulmonary mechanics. Laparoscopic Nissen fundoplication has been associated with a low incidence of severe peri-operative complications although of a different nature to those following the open procedure. We are reporting a rare case of acute cardiovascular collapse secondary to cardiac tamponade during laparoscopic Nissen fundoplication.

Aged↗
PubMed1997

Inhibition of uptake of transferrin-bound iron by human hepatoma cells by nontransferrin-bound iron.

The liver acquires iron from transferrin by transferrin receptor-mediated (TR) and transferrin receptor-independent pathways (NTR) and from nontransferrin-bound iron (NTB-Fe). Iron uptake by the NTR processes involves an iron-carrier mediated step. Experiments, using human hepatoma cells (HuH7) transfected with TR antisense (sense for control) RNA expression vectors to suppress TR expression, were performed to examine the effect of unlabeled NTB-Fe as iron citrate on the uptake of 59Fe-125I-transferrin. This was to determine if the uptake of transferrin-bound iron (Tf-Fe) and NTB-Fe uptake is mediated by a common iron-carrier. Iron citrate inhibited the uptake of 59Fe-transferrin (2.5 micromol/L Fe) in a concentration-dependent manner with a maximum effect when the citrate-iron:Tf-Fe molar ratio was 10:1. Transferrin uptake was not affected. At a lower Tf-Fe concentration of (0.125 micromol/L) when uptake of iron is TR-mediated, a 10-fold molar excess of iron citrate had no effect on Tf-Fe uptake by HuH7 TR antisense and sense cells. However, at a higher Tf-Fe concentration (2.5 micromol/L), when uptake occurs mainly by the NTR-mediated process, there was a 40% reduction in the membrane-bound and intracellular uptake of iron. Iron citrate did not affect the maximum rate (Vmax) of Tf-Fe uptake but the Michaelis-Menten constant (Km) for Tf-Fe uptake by the NTR-mediated process was increased, indicating there was competitive inhibition of Tf-Fe uptake by iron citrate. These results suggest that the uptake of NTB-Fe and Tf-Fe by the NTR- mediated process occurs by the same cellular pathway, using a common iron-carrier.

Analysis of Variance↗
PubMed1996

Angiogenesis factor in endometrial carcinoma: a new prognostic indicator?

OBJECTIVE: Tumor angiogenesis is believed to be a prognostic indicator associated with tumor growth and metastasis. Studies of angiogenesis in breast, prostate, and lung cancer, as well as melanoma, have shown that neovascularization correlates with the likelihood of metastasis and recurrences. The purpose of this study was to evaluate microvessel density as a prognostic factor in endometrial cancer. METHODS: Between 1980 and 1991 the tumor registry identified 25 patients with a diagnosis of recurrent endometrial cancer. These patients were matched with 25 patients with nonrecurrent disease for age, stage, grade, and treatment. The histologic slides of the 50 patients were reviewed. The paraffin blocks were obtained, and the area of the deepest myometrial invasion was selected for staining. The microvessels within the invasive cancer were highlighted by means of immunocytochemical staining to detect factor VIII-related antigen. Microvessels were counted by two investigators who were blinded to the patients' clinical status. Survival data were analyzed with Kaplan-Meier survival curves. RESULTS: Microvessel count was related to likelihood of recurrence, although this trend did not reach statistical significance. Patients with tumors of low capillary density had a mean survival time of 123 months. Patients with tumors of high capillary density had a mean survival time of 75 months (p = 0.02). Among patients with recurrent disease, those with a low capillary count survived a mean of 64 months. Patients with recurrent disease with tumors of high capillary density survived a mean of 45 months (p = 0.002). CONCLUSION: Angiogenesis factor correlates with survival in endometrial carcinoma.

Aged↗
PubMed1996

Inhibition of testosterone 5 alpha-reductase: evidence for tissue-specific regulation of thromboxane A2 receptors.

Testosterone has been implicated as a risk factor for cardiovascular diseases and thromboxane A2 (TXA2) may be an important pathophysiologic mediator for them. Testosterone has been shown to increase TXA2 receptor density in several cell types. Testosterone is reduced at the 5 alpha position to its active metabolite, dihydrotestosterone, by 5 alpha-reductase. We determined the effects of epristeride, a 5 alpha-reductase inhibitor, on the density of TXA2 receptors in rat aortic smooth muscle cells and human erythroleukemia cells, a megakaryocyte-like cell, in vitro, and in rat platelets and aortic membranes in vivo. In rat aortic smooth muscle cells, epristeride significantly (P < .01, n = 5) blocked the effect of testosterone to increase TXA2 receptor density (Bmax: 44 +/- 3, 76 +/- 7, 48 +/- 4 and 46 +/- 4 fmol/mg protein, for control cells, cells treated with testosterone (200 nM), cells treated with testosterone and epristeride (10 nM) and cells treated with epristeride, respectively. Epristeride did not block the effect of testosterone in human erythroleukemia cells. Treatment of male rats with epristeride for 2 weeks significantly (P < .01) decreased TXA2 receptor density in aortic membranes (41 +/- 3 for vehicle, n = 10; 27 +/- 3 fmol/mg protein for epristeride, n = 11) but did not significantly change TXA2 receptor density in platelets. Maximum contractile responses of rat aortas to U46619, a TXA2 mimetic, were significantly (P < .001) lower in epristeride-treated rats than in vehicle-treated rats (4.2 +/- 0.1 for vehicle, n = 16, 3.0 +/- 0.2 g tension for epristeride, n = 15). In conclusion, regulation of expression of TXA2 receptors by testosterone in cells of vascular origin, but not in platelets, appears to be via DHT.

5-alpha Reductase Inhibitors↗
PubMed1995

Fusion of the TEL gene on 12p13 to the AML1 gene on 21q22 in acute lymphoblastic leukemia.

Chromosomal rearrangements involving band 12p13 are found in a wide variety of human leukemias but are particularly common in childhood acute lymphoblastic leukemia. The genes involved in these rearrangements, however, have not been identified. We now report the cloning of a t(12;21) translocation breakpoint involving 12p13 and 21q22 in two cases of childhood pre-B acute lymphoblastic leukemia, in which t(12;21) rearrangements were not initially apparent. The consequence of the translocation is fusion of the helix-loop-helix domain of TEL, an ETS-like putative transcription factor, to the DNA-binding and transactivation domains of the transcription factor AML1. These data show that TEL, previously shown to be fused to the platelet-derived growth factor receptor beta in chronic myelomonocytic leukemia, can be implicated in the pathogenesis of leukemia through its fusion to either a receptor tyrosine kinase or a transcription factor. The TEL-AML1 fusion also indicates that translocations affecting the AML1 gene can be associated with lymphoid, as well as myeloid, malignancy.

Amino Acid Sequence↗
PubMed1995

Investigation of natural genetic variation in the circadian system of Drosophila melanogaster. II. Biometrical analyses of locomotor activity rhythms recorded in constant darkness.

The locomotor activity rhythms of 24 isochromosomal strains of Drosophila melanogaster were recorded in constant conditions, using an experimental design suitable for the serial screening with so many strains using limited equipment. The data obtained were subjected to biometrical genetic analysis. The results show that four characteristics of the rhythms (period, phase, definition, and waveform) display genetically based variation in expression and that each appears to be affected by a range of genes.

Activity Cycles↗
PubMed1995

Clinical and prognostic significance of chromosomal abnormalities in childhood acute myeloid leukemia de novo.

We report on the chromosomal pattern of 120 patients with childhood AML de novo. One hundred and fifteen patients (96%) had adequate samples for analysis; 98 (85%) of these showed clonal karyotypic abnormalities. They were classified into cytogenetic subgroups which were closely correlated with FAB subtypes: t(8;21) and M2 (n = 9); t(15;17) and M3 (n = 12); inv(16) and M4Eo (n = 9); t(9;11) and M5a (n = 10); t(11q23) other than t(9;11) and M4-M5 (n = 11); and t(1;22) and M7 (n = 4). In patients with -7/del(7q) (n = 6), leukemia was preceded by MDS in half of the cases, although they had diverse FAB subtypes. Thirty-seven patients had miscellaneous abnormalities. Despite a high CR rate, patients with t(8;21) had a very poor survival: only one child was event-free at 3 years from diagnosis. One third of patients with t(15;17) died during induction. Those eight who achieved CR fared well: only two relapsed, and six were event-free survivors. Patients with inv(16) had a high remission rate and a long survival: five children were in CR 20 to 136 months. Both groups with t(9;11) and t(11q23) had a high remission rate: however, outcome was superior for the t(9;11) group when compared to either the t(11q23) group (EFS at 3 years +/- SE, 56 +/- 17% vs. 11 +/- 10%, p = 0.07) or to the remaining patients (p = 0.06). Both -7/del(7q) and t(1;22) groups had low CR rates (50%) and poor survival. Cytogenetic analysis identifies clinically distinct subsets of childhood AML and is useful in tailoring treatment for these patients. Favorable cytogenetic groups (t(15;17), inv(16), and t(9;11)) may do well with current therapy protocols, whereas unfavorable groups (t(11q23), t(8;21), -7/del(7q), and t(1;22)) require more effective therapies.

Child↗
PubMed1994

Experimental expansion of the maxillary sinus.

To assess the feasibility of "tissue" expansion as a means of midface advancement for correction of hypoplasia, expanders were placed in the left maxillary sinuses of New Zealand White rabbits. Twenty-one animals were used for the study, all of whom underwent implantation of radiopaque dental amalgam markers adjacent to cranial sutures at 9 days of age. The nonoperative control group (n = 13) underwent no further surgery. At 30 days of age, the experimental group (n = 8) underwent placement of an inflatable 1-mL Silastic tissue expander in the left maxillary sinus. After 1 week, inflation was begun in serial increments of 0.15-mL normal saline to a total volume of approximately 1.05 mL over a 2-week period. Lateral cephalometrograms were obtained at 9, 30, 60, and 90 days of age to measure growth of the craniofacial skeleton. Both groups demonstrated similar growth between 9 and 30 days of age; however, insertion and inflation of the tissue expander resulted in a statistically significant (p < 0.05) increase in posterior facial height, followed, in 30 days, by a significant increase in the length of the anterior cranial base. The remainder of the cranial base and the cranial vault grew without significant differences between the groups. This study demonstrates that changes in facial morphology can be effected in the growing skeleton through tissue expansion and provides further evidence to support the concept of an interrelated facial skeletal-basicranial-neurocranial axis.

Animals↗