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Biomedical subjects

S Kelly

Publications and source records attributed to S Kelly.

At least 19 recordsLinked to original sources
PubMed1992

Red cell filterability determined using the cell transit time analyzer (CTTA): effects of ATP depletion and changes in calcium concentration.

Cell transit time analysis (CTTA) is a new filtrometric technique for assessing red blood cell deformability by measuring the conductivity change caused by passage of erythrocytes through a polycarbonate filter. Most reported studies to date using CTTA have focused on the transit time (TT), the duration of passage of an individual red cell through a micropore. Bulk flow rate has not been previously measured via CTTA. The use of new enzyme based cleaning solutions make it possible to reduce clogging in micropore filters. Therefore, valid measures of the number of red cell transits per unit time (counts/s: C/S) can now be obtained. We evaluated both parameters, TT and C/S, as indicators of red cell filterability. Our goal was to evaluate the effect of metabolic changes shown by alternative techniques to affect red cell deformability. The two best established factors are changes in intracellular [ATP] and [Ca2+]. ATP depletion produces a very small increase in TT but a very marked decrease in C/S. In contrast, the addition of low concentrations of calcium produces an increase in TT with minimal decrease in C/S. The effects of calcium appear to be complex. The substantial changes in intracellular calcium induced by the ionophore A23187 result in a curvilinear pattern of increase in transit times and reduction in counts per s. Lanthanum, which inhibits egress of intracellular calcium, causes an increase in TT with a drop in C/S. We conclude that CTTA demonstrates the same changes in red cell deformability measurable by alternative filtrometric techniques; however, CTTA furnishes two separate and independent parameters which may be used to evaluate red cell deformability.

Adenosine Triphosphate↗
PubMed1992

HLA-identical sibling donor bone marrow transplantation for chronic myeloid leukaemia in first chronic phase: influence of GVHD prophylaxis on outcome.

We have analysed the results of treating 140 consecutive patients with chronic myeloid leukaemia (CML) in chronic phase by bone marrow transplantation (BMT) using marrow from HLA-identical siblings performed between February 1981 and July 1991. Three different regimens were used sequentially to prevent graft-versus-host disease (GVHD): cyclosporin A (CsA) alone (n = 39), T-cell depletion of donor marrow (n = 51) and CsA with methotrexate (MTX) (n = 50). Eighty-four patients (61%) survive at a median of 49 months from BMT (range 3-120). The actuarial overall and leukaemia-free survivals at 5 years were 52% and 41% respectively. The actuarial probabilities of leukaemia-free survival and haematological relapse at 2 years for the CsA only group were 65% and 4%, for the T-cell depletion group 40% and 41% and for the CsA/MTX group 68% and 6% respectively. For the T-cell depletion group the probability of leukaemia-free survival was significantly lower (P less than 0.001) and the probability of relapse significantly higher (P less than 0.001) than for other methods of GVHD prophylaxis; differences between the other two groups were not significant. Previous reports that T-cell depletion with Campath-1M results in a high rate of relapse are confirmed. Patients in the CsA/MTX group have been monitored with cytogenetic and polymerase chain reaction studies for residual BCR/ABL transcripts. We conclude that the combination of CsA/MTX is currently the best available approach to prevention of GVHD after BMT for CML and in our hands it is not associated with a major risk of relapse.

Adolescent↗
PubMed1992

Medical cover for 'The Open' golf championship.

A review of 10 years' provision of medical cover at a major golf championship is presented. The average consultation rate was approximately 1 in 200 of those attending of whom 3% required transfer to hospital, the majority to orthopaedic or general medical departments. Familiarity with acute resuscitation and musculoskeletal complaints is required of the medical attendants. The provision of physiotherapy and chiropody services is essential, especially for the participants' complaints, two-thirds of which affected the axial skeleton. Good communications and close liaison with the Chief Marshal, Police and Ambulance Services are vital.

Emergency Medical Service Communication Systems↗
PubMed1992

Liver transplantation: living-related donations.

The LRLT procedure appears to be a promising alternative and adjunct to conventional liver transplantation. The advantages to this technique are a donor for each recipient, an improved quality of graft, and a reduction in pretransplant mortality in children. The procedure is not without risks, but the overall benefits seem to outweigh these risks, and only future experience will tell otherwise. Will there continue to be a need for such a procedure? We believe there will be, because the number of candidates needing transplantation will continue to grow and the demand for cadaveric organs will never be met. However, the procedure is extremely labor and resource intensive, and it is our belief that only a handful of large major medical centers will be able to adopt a live-donor program.

Adult↗
PubMed1991

Loss of both CSF1R (FMS) alleles in patients with myelodysplasia and a chromosome 5 deletion.

A high proportion of patients with myelodysplasia show characteristic karyotypic abnormalities in bone marrow cells. The most distinctive of the myelodysplastic syndromes is the 5q- syndrome characterized by refractory anemia, poorly lobulated megakaryocytes, and an interstitial deletion of the long arm of chromosome 5 (5q deletion) as the sole karyotypic abnormality. Recently, several genes encoding hemopoietic growth factors and receptors, comprising the interleukins 3, 4, and 5, macrophage colony-stimulating factor, granulocyte/macrophage-colony-stimulating factor, and the receptor for macrophage-colony-stimulating factor [the CSF1R (formerly FMS) gene product], have been localized to the long arm of chromosome 5, and there has been much speculation that deletion of one or more of these genes may be critical to the pathogenesis of the associated myeloid disorders. One candidate gene is CSF1R, which is required for normal proliferation and differentiation of hemopoietic cells of the myeloid lineage. We have carried out a molecular examination of the CSF1R, both on the 5q- chromosome and on the apparently normal homologous chromosome 5, in 10 patients with myelodysplasia and a 5q deletion. We have found, using restriction fragment length polymorphism analysis and gene dosage experiments, that all 10 patients showed deletion of CSF1R; 6 of 10 were hemizygous and 4 of 10 homozygous for CSF1R loss. The homozygous CSF1R loss has been confirmed in 2 patients by an in situ hybridization technique comparing the signal in affected cells to that in control sex-mismatched cells on the same slides. In those patients considered to have homozygous CSF1R loss by DNA experiments the gene was deleted from the 5q chromosome in all cells and from the apparently normal chromosome 5 in a subset of cells. This loss of one CSF1R allele, together with loss in some cells of the remaining allele on the homologous chromosome 5, in patients with myelodysplasia indicates that this is a region of critical gene loss on 5q. The loss of the hemopoietic growth factor receptor gene CSF1R may be important in the pathogenesis of human myeloid leukemia.

Adult↗
PubMed1991

Stabilization of the shikimate pathway enzyme dehydroquinase by covalently bound ligand.

Reversible binding of a ligand to an enzyme active site can elicit a variety of changes in the protein, such as conformational changes (close to the site of binding or communicated over long distances), changes in the ionization state of surrounding amino acid side chains, changes in the interaction of the target protein with other subunits (or other proteins), or even changes in the thermodynamic stability of the protein. Relatively little attention has been given to studying these effects in proteins to which the ligand has been irreversibly bound, yet this can be a convenient way of studying the effects of ligand binding in the absence of association/dissociation equilibria. We report the dramatic changes which occur to the shikimate pathway enzyme dehydroquinase when ligand is attached to its active site after borohydride reduction of the mechanistically important Schiff's base intermediates. The effects of this modification have been characterized by limited proteolysis, circular dichroism, guanidine hydrochloride denaturation, and differential scanning calorimetry. The conclusions from these studies are that although anchoring the ligand at the active site does not cause a gross change in conformation, it does increase markedly the conformational stability of the protein. This is conclusively established by three separate experiments: 1) the modified protein is completely resistant to proteases, whereas the unmodified protein is very susceptible to proteolysis; 2) the concentration of guanidine hydrochloride required to unfold the ligand-linked dehydroquinase is 3-4-fold greater than that of the unmodified protein; 3) the melting temperature (Tm) of the modified protein is 40 degrees C higher than that of the unmodified protein. These results are a very clear example of the thermodynamic link between ligand binding, conformational stability, and proteolytic susceptibility in vitro and will be a useful system for dissecting the contributions of individual protein-ligand interactions to these parameters.

Calorimetry, Differential Scanning↗
PubMed1991

Translocation 1;7 in hematologic disorders--a report of three further cases. Absence of amplification of the gene for the epidermal growth factor receptor.

We report three new cases with a hematologic disorder and the unbalanced translocation der(1)t(1;7)(p11;p11). It has been speculated that the gene for the epidermal growth factor receptor, localized to the short arm of chromosome 7, might be amplified in cases with this translocation. We have demonstrated that there is no amplification of this gene in these three cases.

Aged↗
PubMed1991

Clonality of cell populations in refractory anaemia using combined approach of gene loss and X-linked restriction fragment length polymorphism-methylation analyses.

We have used X-linked restriction fragment length polymorphism (RFLP)-methylation and gene deletion analyses to investigate the nature of the progenitor cell of origin in the myelodysplastic syndromes (MDS). Gene deletion studies were performed on the granulocyte and T-lymphocyte fractions of six women with refractory anaemia (RA) and either a partial deletion of the long arm of chromosome 5 (5q-) or monosomy 7. All six showed gene loss in the granulocyte but not the T-lymphocyte fractions, indicating monoclonality of the granulocytes but not the T-lymphocytes. In order to further investigate this finding, we subsequently performed X-RFLP-methylation studies using the probe M27 beta, and also a probe for the phosphoglycerate kinase (PGK) gene. These studies have confirmed the monoclonality of the granulocytes and the polyclonality of the T-lymphocytes in these cases. Our findings suggest that in this group of patients with MDS the T-lymphocytes were not involved in the disorder, and furthermore, in the one case where B-lymphocytes were also available, that the progenitor cell of origin was restricted to the myeloid lineage.

Anemia, Refractory↗
PubMed1990

Yeast RNA polymerase I. Derivatization of the 190 and 135 subunits by 4-thiouridine monophosphate positioned uniquely at the 3' terminus of an enzyme-bound 32P-containing transcript initiated by a triribonucleotide primer on synthetic single-stranded DNA.

Specific transcription complexes were formed with yeast RNA polymerase I using a cognate oligoribotri-nucleotide primer (GCG) to initiate transcription on short synthetic single-stranded DNA templates. The templates were designed to limit the incorporation of a photoprobe, 4-thiouridine triphosphate, to a single unique position at the 3' terminus of the product RNA (position 12, 13, 14, or 15). The resulting transcription complexes were photolyzed to cross-link the bound transcript (radiolabeled with [alpha-32P]CTP) to the protein with the probe located at the catalytic site. Separation of the protein subunit components by 5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis and analysis by autoradiography and silver staining revealed that the two largest subunits (A190 and A135) were radiolabeled. The ratio of subunit labeling (A190/A135) decreased as the RNA transcript increased from 12 to 15 nucleotides in length. This decrease in ratio resulted from a progressive reduction of A190 subunit labeling while the A135 subunit derivatization remained essentially constant. It was also observed that the DNA template was radiolabeled.

Affinity Labels↗
PubMed1990

Percutaneous intravascular US as adjunct to catheter-based interventions: preliminary experience in patients with peripheral vascular disease.

Catheter-based ultrasound (US) transducers may be introduced into the vascular system to record high-resolution images of the vessel wall and lumen. The potential advantages and existing liabilities of percutaneous intravascular US as an adjunct to transluminal vascular recanalization were investigated. A 6.6-F braided, polyethylene catheter enclosing a rotary drive shaft with a single-element, 20-MHz transducer at the distal tip was used in 17 patients undergoing percutaneous transluminal (balloon) angioplasty (PTA) alone (10 patients), PTA with implantation of an endovascular stent (two patients), atherectomy alone (two patients), or laser angioplasty with PTA and/or atherectomy (three patients). The arteries treated and examined included the common iliac in five patients, the external iliac in two, the superficial femoral in nine, and a vein graft-arterial anastomosis in one. In 14 cases PTA was employed as sole or adjunctive therapy; plaque cracks were clearly delineated with intravascular US in all 14 (100%) and dissections were observed in 11 (78%). Plaque-arterial wall disruption was less prominent in the arteries treated with mechanical atherectomy. The results of laser angioplasty reflected the adjunctive modality employed. After stent implantation, serial intravascular US documented effacement of PTA-induced plaque cracks and/or dissections. Intravascular US also aided in the quantitative assessment of luminal cross-sectional areas after the procedures (19.0-51.8 mm2). The observations recorded in this preliminary group of 17 patients illustrate the potential utility of intravascular US as an adjunct to conventional angiography in patients undergoing percutaneous revascularization.

Aged↗
PubMed1990

DNA flow cytometry of myocardial cell nuclei in paraffin-embedded, human autopsy, cardiac tissue.

Changes in nuclear DNA occur in myocytes as they grow and hypertrophy. We used DNA flow cytometry to study myocardial nuclei from paraffin-embedded human autopsy tissue. Forty hearts ranging from 310-1040 g were studied. Histograms generated for each heart showed peaks at the 2N and 4N positions. Two of 9 hearts weighing 310-430 g had 8N peaks as well. Fourteen of 17 hearts weighing 450-690 g also had 8N peaks but no 16N peaks. Twelve of 14 hearts weighing 710 to 1040 g had 8N peaks and 4 had 16N peaks as well. Contingency analysis showed statistically significant differences in the ploidy of nuclei from the three different groups of hearts. This study corroborates previous work indicating that DNA ploidy in myocardium increases with hypertrophy. Thus, flow cytometry of paraffin-embedded myocardium should be a useful technique to study DNA from archival material, obviating the need for fresh or frozen tissue.

Cardiomegaly↗
PubMed1979

Fluorimetric assay of acid lipase in human leukocytes.

A fluorimetric assay for leukocyte acid lipase, the enzyme defect in Wolman disease, is described. The method requires a smaller volume of blood and can be performed more rapidly than the present colorimetric assay for the leukocyte enzyme.

Clinical Enzyme Tests↗