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Biomedical subjects

A Haynes

Publications and source records attributed to A Haynes.

At least 19 recordsLinked to original sources
PubMed2001

Theoretical, thermodynamic, spectroscopic, and structural studies of the consequences of one-electron oxidation on the Fe-X bonds in 17- and 18-electron Cp*Fe(dppe)X complexes (X = F, Cl, Br, I, H, CH3).

The compounds Cp*Fe(dppe)X ([Fe]X) and the corresponding cation radicals [Fe*]X*+ are available for the series X = F, Cl, Br, I, H, CH3. This has allowed for a detailed investigation of the dependence of the nature of Fe-X bonding on the identity of X and the oxidation state (charge) of the complex. Cyclic voltammetry demonstrates that the electrode potentials for the [Fe]X0/+ couples decrease in the order I > Br > Cl > H > F > CH3. An "inverse halide order" is seen, in which the most electronegative X leads to the most easily oxidized complex. This suggests that F is the best donor among the halides. The halide trend is also reflected in NMR spectroscopic data. Mössbauer spectroscopy data also suggest that the F ligand is a strong donor (relative to H and CH3) in [Fe*]X*+. DFT calculations on CpFe(dpe)X ([Fe]X) model complexes nicely reproduce the trend in the electrode potentials for the [Fe*]X0/+ couples. Analysis of the theoretical data within the halogen series indicates that the energy of the [Fe]X HOMO does not correlate with the extent of its Fe(d(pi))-X(p(pi)) antibonding character, which varies in the order I > Br > Cl > F, but rather depends on the destabilizing electrostatic effect caused by X. This effect varies in the order F > Cl > Br > I. A thermochemical cycle that incorporates the [Fe*]X0/+ and [Fe*]0/+ electrode potentials was used to investigate the effect of the oxidation state of the complex on the homolytic bond dissociation energy (BDEhom), defined for the processes Fe-X --> Fe* + X* and Fe-X*+ --> Fe*+ + X*. For all X, it was found that a one-electron oxidation leads to a weakening of the Fe-X bond. This trend was reproduced by the DFT calculations. On the other hand, IR nu(Fe-X) spectroscopy data showed an increase in the stretching frequencies for X = H and Cl upon oxidation. X-ray crystallographic data showed a shortening of the Fe-Cl bond upon oxidation. The trends in IR and Fe-Cl bond distances were reproduced in the DFT calculations. The combined data therefore suggest that oxidation leads to weaker, but shorter, Fe-X bonds. A second thermochemical cycle was applied to investigate the effect of the one-electron oxidation on the heterolytic bond dissociation energies (BDEhet), defined for the processes Fe-X --> Fe+ + X- and Fe-X*+ --> Fe2+ + X-. In this case, the oxidation led to bond strengthening in all cases. The computed BDE values have been analyzed within Ziegler's transition state methodology and decomposed into two components, one electrostatic and one covalent, describing the interaction between the unrelaxed fragments. In all the computed BDEhom and BDEhet values of the [Fe]X models the electrostatic component is important. This helps to understand their respective variations upon oxidation.

Journal Article↗
PubMed2001

Identification, mapping, and phylogenetic analysis of three novel chicken CC chemokines.

We have identified three novel chicken CC chemokine genes among cDNA clones derived from lipopolysaccharide-stimulated cells of the chicken macrophage cell line HD11. Two of these chemokines show DNA sequence homology to the mammalian genes SCYA20 (MIP-3alpha) and SCYA5 (RANTES), while the third shows similar levels of homology to several mammalian CC chemokines. Sequencing of genomic DNA showed that all three chicken chemokines possess the three-exon structure and conserved intron positions typical of mammalian CC chemokines. Genetic mapping of the three chicken chemokines locates them in three chromosomal regions which correspond to regions containing homologous chemokines in humans. Phylogenetic analysis of the currently known chicken and human chemokines suggests that individual chicken and human chemokines derive from common ancestral genes in patterns that reflect their genomic positions, indicating that the diversity of chemokine genes pre-dated avian-mammalian divergence. Since the function of the chemokines is principally to act as intermediates between stimulated cells and specific subsets of responding immune cells, this suggests that the complex organization of the immune system and diversity of responding cells were largely in place at that time.

Animals↗
PubMed2001

A radiation hybrid transcript map of the mouse genome.

Expressed-sequence tag (EST) maps are an adjunct to sequence-based analytical methods of gene detection and localization for those species for which such data are available, and provide anchors for high-density homology and orthology mapping in species for which large-scale sequencing has yet to be done. Species for which radiation hybrid-based transcript maps have been established include human, rat, mouse, dog, cat and zebrafish. We have established a comprehensive first-generation-placement radiation hybrid map of the mouse consisting of 5,904 mapped markers (3,993 ESTs and 1,911 sequence-tagged sites (STSs)). The mapped ESTs, which often originate from small-EST clusters, are enriched for genes expressed during early mouse embryogenesis and are probably different from those localized in humans. We have confirmed by in situ hybridization that even singleton ESTs, which are usually not retained for mapping studies, may represent bona fide transcribed sequences. Our studies on mouse chromosomes 12 and 14 orthologous to human chromosome 14 show the power of our radiation hybrid map as a predictive tool for orthology mapping in humans.

Animals↗
PubMed2001

High-dose ifosfamide in combination with etoposide and epirubicin (IVE) in the treatment of relapsed/refractory Hodgkin's disease and non-Hodgkin's lymphoma: a report on toxicity and efficacy.

One hundred and seven patients (61 with diffuse large B-cell non-Hodgkin's lymphomas and 46 with Hodgkin's disease) in relapse or following of primary therapy received ifosfamide 3 g/m2 i.v. daily for 3 days in combination with epirubicin 50 mg/m2 i.v. day 1 and etoposide 200 mg/m2 i.v. days 1-3. Of the 46 patients with Hodgkin's disease (28 male, 18 female, and a median age of 28 years) 85% of patients had a response to treatment, with 17 achieving complete remission and 11 good partial remission. Twenty-eight proceeded to autologous bone marrow or peripheral blood stem cell transplantation. Twenty-three patients remain alive in continuous remission with a follow-up of 12-61 months. The median overall survival time for all patients in this group is 36 months. Haematological toxicity, particularly WHO Grade IV neutropenia, occurred in all patients but improved over the three courses of treatment. There was no major non-haematological toxicity. Further trials of this regimen in this clinical situation are indicated. The patients with non-Hodgkin's lymphomas in this study had diffuse large B-cell lymphomas and had only received first-line treatment. Twenty had primarily refractory disease, 15 had only achieved partial remissions (PR), and 26 had developed relapse following primary treatment. The overall response rate was 43%; it was 60% for those who had achieved initial PR, 58% for those in relapse after an initial CR or very good PR following initial therapy, but only 10% for those with primarily refractory disease. Tolerance to the regimen was similar to that observed in treatment of the patients with Hodgkin's disease and many were able to undergo stem cell collection, following mobilization with this regimen. The 2-year overall survival result was 22% for patients with some response to first-line treatment but 0% for primary refractory patients.

Adolescent↗
PubMed2000

Mice overexpressing human uncoupling protein-3 in skeletal muscle are hyperphagic and lean.

Uncoupling protein-3 (UCP-3) is a recently identified member of the mitochondrial transporter superfamily that is expressed predominantly in skeletal muscle. However, its close relative UCP-1 is expressed exclusively in brown adipose tissue, a tissue whose main function is fat combustion and thermogenesis. Studies on the expression of UCP-3 in animals and humans in different physiological situations support a role for UCP-3 in energy balance and lipid metabolism. However, direct evidence for these roles is lacking. Here we describe the creation of transgenic mice that overexpress human UCP-3 in skeletal muscle. These mice are hyperphagic but weigh less than their wild-type littermates. Magnetic resonance imaging shows a striking reduction in adipose tissue mass. The mice also exhibit lower fasting plasma glucose and insulin levels and an increased glucose clearance rate. This provides evidence that skeletal muscle UCP-3 has the potential to influence metabolic rate and glucose homeostasis in the whole animal.

Adipose Tissue↗
PubMed2000

Allogeneic haemopoietic stem cell transplantation for multiple myeloma or plasma cell leukaemia using fractionated total body radiation and high-dose melphalan conditioning.

We have evaluated the outcome of allogeneic haemopoietic stem cell transplantation for multiple myeloma using a conditioning regimen comprising fractionated total body irradiation and high-dose melphalan (110 mg/m2). The study comprised 25 patients (median age 49 years) who had been transplanted by either bone marrow (n = 13) or G-CSF mobilized peripheral blood stem cells (n = 12). Overall transplant-related mortality was 30% but was lower for patients < 50 years of age at transplant (21%). The main cause of treatment-related mortality was viral infection. Of the 19 patients evaluable post-transplant, 17 have so far achieved complete remissions. Currently, with a median follow-up of 3.4 years, 18 out of 25 patients are alive, of whom 15 are in continuing complete remission (CR) and 2 in second remission after suffering localized relapses, which were treated with radiotherapy and donor leucocyte infusions. Patients transplanted after 1 line of previous therapy, < 50 years of age and receiving peripheral blood stem cells (PBSC) rather than bone marrow (BM) had a superior outcome, although there was no statistically significant factor. We conclude that allogeneic transplantation should be considered as a potentially curative option for younger patients with myeloma and that the regimen using fractionated total body irradiation and melphalan has a high CR rate and a relatively low risk of treatment-related mortality, particularly in younger patients.

Adult↗
PubMed2000

High dose ifosfamide in combination with etoposide and epirubicin followed by autologous stem cell transplantation in the treatment of relapsed/refractory Hodgkin's disease: a report on toxicity and efficacy.

Patients with Hodgkin's disease (HD) refractory to first line chemotherapy and those who have rapid or multiple relapses have a very poor prognosis. With the increasing use of hybrid chemotherapy these patients will have been exposed to many of the drugs active in HD so it is important to develop salvage regimens that are novel and demonstrate activity in this group of patients. We report the use of a continuous high dose infusion of ïfosfamide at a dose of 9g/m(2) over 3 days in combination with etoposide and epirubicin followed by autologous stem cell transplant with either BEAM or Melphalan/VP16 conditioning in this difficult group. Forty six patients (28M:18F) with a median age of 28 years (range 13-45) were treated. Overall 39 out of 46 (85%) patients responded to treatment, with 17 achieving complete remission and 11 a good partial remission; 28 proceeded to autologous bone marrow/stem cell transplantation. In total, 23 patients are alive and in continuous remission with a follow up of between 12 and 61 months. Median overall survival for the whole group is 36 months. Haematological toxicity, particularly neutropenia (WHO grade IV), was observed in all cases but improved over the 3 courses of treatment in all patients. Non-haematological toxicity was not a major problem; no significant cardiac, hepatic, renal, pulmonary or neuro toxicity was observed and there were no deaths on treatment. This regime shows promise in patients with difficult Hodgkin's disease and warrants further study.

Adolescent↗
PubMed1999

Variability of polymerase chain reaction detection of the bcl-2-IgH translocation in an international multicentre study.

BACKGROUND: The capacity of the polymerase chain reaction (PCR) to detect very low numbers of cells bearing a t(14;18) translocation has led to its application in assessment of the results of treatment for follicular lymphoma, and suggestions that therapy might be guided by molecular studies. To test the reliability of PCR a collaborative study was undertaken to compare results from different laboratories in Europe and North America. METHODS: Twenty laboratories with records of publication in molecular diagnostics were sent blood from normal donors with varying numbers of t(14;18)-bearing cells added from a cell line with a translocation in the major breakpoint region (MBR) of the bcl-2 gene. Samples contained 1000, 100, 10, 1 or 0 cells per ml of whole blood and were sent blinded in duplicate. PCR methodology varied widely, with the total number of amplification cycles between 30 and 70, and 13 different primers used for the MBR region. Twelve laboratories used nested PCR and eight single round amplification. RESULTS: The sensitivity of nested and single round PCR was similar at 100 cells/ml but below this the nested method proved significantly more sensitive. The false positive rate was 28%, with 11 samples from 9 laboratories reported as positive when no t(14;18) cells were added. PCR product size and sequence analysis showed that false positives were due to contamination from cell-line DNA rather than background translocations in the donors. There was no significant difference in false positive rates between nested and single round techniques. CONCLUSION: The polymerase chain reaction to detect bcl-2-IgH rearrangements is presently carried out with widely disparate results. Further effort is required to bring forward a standard PCR protocol which can be re-tested in different laboratories to improve accuracy and reproducibility. The application of quantitative techniques such as real-time PCR may resolve many of the problems presently encountered.

Adult↗
PubMed1999

Mechanisms of relapse in acute leukaemia: involvement of p53 mutated subclones in disease progression in acute lymphoblastic leukaemia.

Mutations of the p53 tumour suppressor gene are infrequent at presentation of both acute myeloblastic leukaemia (AML) and acute lymphoblastic leukaemia (ALL), being found in between 5-10% of AML and 2-3% of ALL. Here we have studied the frequency of detection of p53 mutations at relapse of both AML and B-precursor ALL. In those patients with detectable mutations at relapse we investigated whether the mutation was detectable at presentation and was thus an early initiating event or whether it had arisen as a late event associated with relapse. Bone marrow samples from 55 adults and children with relapsed AML (n = 41) or ALL (n = 14) were analysed for p53 gene alterations by direct sequencing of exons 5-9. For samples where a p53 mutation was found at relapse, analysis of presentation samples was carried out by direct sequencing of the exon involved, or by allele-specific polymerase chain reaction (PCR) if the mutation could not be detected using direct sequencing. A p53 mutated gene was found at relapse in seven out of 55 cases. The frequency was higher in relapsed ALL (four out of 14 cases; 28.6%) compared to AML (three out of 41 cases; 7.3%). In five out of the seven cases presentation samples were available to study for the presence of the mutation. In two out of two AML patients the p53 mutation was detectable in the presentation sample by direct sequencing. In three ALL patients analysis of presentation material by direct sequencing showed a small mutant peak in one case, the other two being negative despite the sample analysed containing > 90% blast cells. However in both of these patients, the presence of p53 mutation was confirmed in the presentation sample using allele-specific PCR. In one of these patients the emergence of a subclone at relapse was confirmed by clonality analysis using IgH fingerprinting. Our results confirm that in ALL p53 mutations are present in a proportion of patients at relapse. Furthermore cells carrying the mutation are detectable at presentation in a minor clone suggesting that p53 mutations in ALL may be a mechanism contributing to disease relapse.

Adolescent↗
PubMed1999

Mobilisation of peripheral blood stem cells with IVE and G-CSF improves CD34+ cell yields and engraftment in patients with non-Hodgkin's lymphomas and Hodgkin's disease.

The transplantation of mobilised peripheral blood stem cells is associated with more rapid engraftment than marrow transplantation. We have previously reported that G-IVE (G-CSF, ifosphamide, VP-16, epirubicin) improves the yield of CD34+ cells mobilised in patients with lymphoproliferative disorders compared with cyclophosphamide 3 g/m2 and G-CSF (G/CYCLO). In this study we have extended these observations to a larger series of patients including different lymphoma subtypes. Ninety-seven patients undergoing stem cell mobilisation were studied. Forty-two patients with lymphoproliferative disorders received G-IVE for mobilisation and 55 patients G/CYCLO. The median number of mobilised CD34+cells per leucapheresis was significantly higher for those patients receiving G-IVE: 5.82 x 106/kg (0.19-36) compared with 1.2 x 106/kg (0.04-17), P < 0.001 which resulted in a significantly reduced number of leucapheresis procedures performed in the G-IVE group. When patients were analysed dependent on underlying disease G-IVE mobilised significantly more CD34+cells per leucapheresis for all lymphoma types reaching 8.41 x 10(6)/kg (0.2-32) compared to 1.32 x 10(6)/kg (0. 06-17) for patients with high-grade NHL mobilised with G-IVE and C-GCSF respectively (P = 0.012). For patients with low-grade NHL 3. 12 x 10(6)/kg (0.10-24.39) compared to 1.08 x 10(6)/kg (0.04-9.74) were collected (P = 0.04) and for patients with Hodgkin's disease 3.02 x 10(6)/kg (1.48-36) and 1.04 x 10(6)/kg (0.1-12.3) (P = 0.001). Mobilisation with G-IVE resulted in the achievement of clinically significant CD34+ cell thresholds in a significantly higher proportion of patients compared to cyclophosphamide and G-CSF reaching >2.5 x 10(6)/kg CD34+ cells in 88% vs 62% (P = 0.004), >5 x 10(6)/kg in 67% vs18% (P = 0.001) and >10 x 10(6)/kg in 31% vs 14.5% (P = 0.05). Furthermore, an analysis of engraftment demonstrated that there was a significant reduction in the time to achieve platelet counts of >20 and >50 x 10(9)/l in patients receiving each incremental dose of CD34+ cells. We conclude that G-IVE mobilizes significantly more CD34+cells than G/CYCLO in patients with lymphoproliferative disorders. This effect is consistent in patients with high-grade NHL, low-grade NHL and HD and results in fewer failed stem collections and increased CD34+ cells available for transplantation which results in significantly accelerated platelet engraftment post transplant.

Adult↗
PubMed1999

Generation of anti-idiotype immune responses following vaccination with idiotype-protein pulsed dendritic cells in myeloma.

Myeloma cells produce immunoglobulin which is unique to the malignant clone and presents antigenic determinants, or idiotypes, which may function as a tumour-specific antigen. The availability of significant quantities of idiotype protein in the serum makes immunotherapeutic strategies utilizing this protein to generate an anti-idiotype immune response an attractive prospect. We treated two patients with advanced refractory myeloma with a series of four vaccinations using autologous idiotype-protein pulsed dendritic cells combined with adjuvant GM-CSF. The vaccinations were well tolerated with a mild fever post-vaccination in one patient. An idiotype-specific T-cell proliferative response developed in both patients. This T-cell response was associated with the production of gamma-interferon, indicating a TH-1-like response. Furthermore, one patient developed anti-idiotype IgM antibodies. However, no idiotype-specific cytotoxic T-cell response could be demonstrated. Further investigation is warranted to define the optimal conditions for dendritic cell culture and priming to maximize the anti-tumour immune response.

Antibodies, Anti-Idiotypic↗
PubMed1999

Biomechanical analysis of supracondylar femoral fractures fixed with modern retrograde intramedullary nails.

OBJECTIVES: Several new retrograde supracondylar intramedullary nails have been developed to specifically address fractures of the distal femur. The nails appear clinically effective, but there are few biomechanical data documenting the stability of the fixation or the mechanical stiffness of the different designs. The goal of this study was to assess the torsional and bending stiffness of four designs of intramedullary nails developed for this application. METHODS: Four nail designs were tested in torsion and bending to determine system stiffness: Ace supracondylar, Richards "five hole" and "multi-hole" supracondylar, and Biomet retrograde. The nails were inserted into cadaveric femurs in which a one-centimeter distraction osteotomy had been created seven centimeters proximal to the condyles. The constructs were then tested on an Instron biaxial testing system. RESULTS: There were no statistically significant differences in bending stiffness among the groups of nails (range 0.79 to 1.18 newtons/meter; p > 0.1). However, the Ace nails (1.10 newtonmeters/degree) did exhibit a statistically lower torsional stiffness compared with the other nails (2.20 to 2.21 newton-meters/ degree; p < 0. 1). No differences were noted as a function of the number of locking holes. CONCLUSIONS: The bending stiffness of four currently available designs of retrograde intramedullary nails does not appear to be dependent on design variations. The torsional stiffness did vary among the four designs, but this was not determined by the number of fixation holes provided. It appears that a well-placed retrograde supracondylar nail of modern design should have sufficient stiffness to support the femur and provide stability during fracture healing.

Biomechanical Phenomena↗
PubMed1998

A high-resolution microsatellite map of the mouse genome.

The European Collaborative Interspecific Backcross (EUCIB) resource was constructed for the purposes of high-resolution genetic mapping of the mouse genome (). The large Mus spretus/C57BL/6 backcross of 982 progeny has a genetic resolution of 0.3 cM at the 95% confidence level ( approximately 500 kb in the mouse genome). We have used the EUCIB mapping resource to develop a genome-wide high-resolution genetic map incorporating 3368 microsatellites. The microsatellites are distributed among 2302 genetically separated bins with 1.46 markers per bin on average. Average bin separation is 0.61 cM. This high-resolution genetic map will aid the construction of a robust physical map of the mouse genome.

Animals↗
PubMed1997

Effects of intracerebroventricular infusion of leptin in obese Zucker rats.

The obese Zucker rat (OZR) exhibits a missense mutation in the cDNA for the leptin receptor, producing a single amino acid substitution in the extracellular domain of the receptor. A mutation in the leptin receptor gene of the db/db mouse prevents the synthesis of the long splice variant of the receptor. The possibility that the OZR, like the db/db mouse, is refractory to the actions of murine leptin was tested by infusing the protein intracerebroventricularly via a minipump for 7 days. Lean Zucker rats (LZR) infused with leptin acted as positive controls, and other groups of OZR and LZR were infused with vehicle. In LZR, leptin reduced bodyweight and food intake and increased brown adipose tissue (BAT) temperature. Plasma corticosterone increased (61%) in these rats, and plasma triglycerides fell (78%). Leptin treatment improved tolerance to an oral glucose load (16% reduction in the area under the blood glucose curve) while lowering plasma insulin. In OZR, the actions of leptin were blunted. Food intake was slightly, but not significantly, reduced. Although there was a reduction in the rate of increase in body mass, the effect of leptin was about half that seen in LZR. BAT temperature and glucose tolerance were unchanged. In contrast to the elevated plasma corticosterone seen in LZR, leptin reduced the level of this hormone (27%) in OZR. In OZR and LZR treated with leptin, the plasma leptin levels were increased 24-fold and 47-fold, respectively. The results suggest that leptin retains some efficacy in OZR, although these rats are less responsive than LZR.

Adipose Tissue, Brown↗
PubMed1997

The use of an all oral chemotherapy (idarubicin and etoposide) in the treatment of acute myeloid leukaemia in the elderly: a report of toxicity and efficacy.

Acute myeloid leukaemia (AML) is predominantly a disease of the elderly but such patients are not always appropriate candidates for intensive intravenous (i.v.) based treatment regimens. The development of the anthracycline idarubicin which is highly effective in the treatment of AML and is active when given orally has made it possible to design anti-leukaemic regimens which may be given orally and be particularly useful in those elderly patients with AML considered unsuitable for standard intensive aggressive treatments. We have assessed an oral regimen combining idarubicin 30 mg/m2 and etoposide 80 mg/m2 for 3 consecutive days as initial treatment in 28 elderly patients with AML (median age 69 years, range 56-81) who were not considered suitable for more intensive i.v. chemotherapy schedules. Following informed consent, two patients died before treatment began and one patient withdrew prior to treatment. Twenty-five patients underwent one to four courses of treatment. The schedule was well tolerated with minor nonhaematological toxicity. The first course was given in hospital, eight of 21 subsequent courses of treatment were given entirely as an out-patient. Eleven patients responded to treatment with nine (36%) achieving complete remission (CR). The median survival for all patients was 3 months, but for the nine who achieved a CR it is 9 months with six patients still alive, five in first CR and one in second CR. We conclude that a combination of idarubicin and etoposide given orally as first-line treatment in elderly patients with AML is safe and effective. In some patients this means treatment and follow-up can be given entirely on an out-patient basis.

Acute Disease↗