Biomedical subjects
Publications and source records attributed to P Cooke.
Chromosome banding studies were carried out on both partners of 182 consecutive couples with a history of two or more spontaneous abortions. Seventeen abnormal karyotypes were detected. This represents a frequency of 4.67 per cent, which is higher than hitherto reported. The pregnancy outcome in 105 couples with normal and abnormal karyotype was compared and no significant difference was found.
The effects of NMR line-scan imaging procedures and static homogeneous magnetic fields of 0.5 and 1.0 tesla on cells from human blood have been investigated by examining their influence on the frequency of gross lesions, sister chromatid exchanges and on the proportion of amodal cells. Cultured human blood cells have also been submitted to extended NMR imaging exposure during active growth and division. Neither treatment had any significant effect on any of the parameters measured.
During the course of a 30 month study period, 26 patients with typical chronic granulocytic leukaemia (CGL) developed karyotype abnormalities in addition to the Philadelphia (Ph1) chromosome. All cases had received at least 14 months continuous low dose busulphan, and the chromosome changes were found before clinical transformation in six patients and at the time this occurred in 20. Survival following the discovery of these additional abnormalities was short, with a median of 11 weeks for the whole group. Trisomy 8 was the commonest additional chromosome abnormality, but no one karyotype change was clearly associated with shorter survival than another. 23 of the 26 have died as a direct result of their disease, forming part of a total of 40 deaths from typical CGL encountered during the study period where karyotype analyses were performed during the terminal stages of disease. Of these 40, only two (5%) patients showed no chromosome abnormalities extra to the Ph1 prior to death. (The 17 non-study patients who died were similar in all respects to the 23 from the study group, but had no prior chromosome studies performed during the chronic phase of the disease.) It is suggested that an expanding aneuploid or pseudodiploid clone arising from the leukaemic cells during the benign phase of CGL can be used to mark the sometimes ill-defined onset of the malignant phase in all but a small proportion of cases.
Explore the source record for details and available documents.
Doppler pulse recordings in a patient with asymptomatic popliteal entrapment were compared with those in 25 normal subjects. A drop in pulse amplitude and ankle systolic pressure produced by forcible leg extension and active foot plantar flexion distinguished the patient with the anomaly from the controls, in whom no change was noted during these manoeuvres. This simple, non-invasive test thus diagnosed a potentially limb-threatening congenital abnormality in an asymptomatic patient with equivocal arteriographic findings.
There are three classes of myofilaments in vertebrate smooth muscle fibers. The thin filaments correspond to actin and the thick filaments are identified with myosin. The third class of myofilaments (100 A diam) is distinguished from both the actin and the myosin on the basis of fine structure, solubility, and pattern of localization in the muscle fibers. Direct structural evidence is presented to show that the 100A filament constitute an integrated filamentous network with the dense bodies in the sarcoplasm, and that they are not connected to either the actin or myosin filaments. Examination of (a) isolated dense bodies, (b) series of consecutive sections through the dense bodies, and (c) redistributed dense bodies in stretched muscle fibers supports this conclusion. It follows that the 100-A filaments complexes constitute a structrally distinct filamentous network. Analysis of polyacrylamide gels after electrophoresis of cell fractions that are enriched with respect to the 100-A filaments shows the presence of a new muscle protein with a molecular weight of 55,000. This protein can form filamentous segments that closely resemble in structure the native, isolated 100-A filaments. The results indicate that the filamentous network has a structure and composition that distinguish it from the actin and myosin in vertebrate smooth muscle.
Ideograms of chromosomes obtained by the trypsin/Leishman method are presented in which the size and position of the bands of chromosomes at different stages of contraction have been defined by measurement. A hypothesis is suggested which could explain the changes observed in the banding pattern between stages of condensation.
The distribution of X-ray induced aberrations between trypsin-banded regions within human chromosomes has been studied in over a thousand cells from normal and abnormal individuals. An analysis of this data has been performed for each type of aberration separately, taking into account the relative amount of material at risk in reach region. A number of significant deviations from expectation were detected but many of these could be explained in terms of the failure of detection of some aberrations.
Explore the source record for details and available documents.
The studies presented here confirm earlier reports that an actin-like protein is abundant in brain. However, when the traditional procedures for isolating muscle actin are applied to brain, many different proteins are extracted. Tubulin, a major protein in brain with properties similar to actin, is the major constituent. A method is described for isolating the "brain actin" to a purity of 90-95%. The isolation method begins with an extraction of bovine brain in low ionic strength buffer with ATP and sucrose. The extract is treated with NH4SO4, MgCl, and KCl and incubated at 37 degrees C. A precipitate is formed which contains primarily tubulin and brain actin. Resolubilization of the brain actin is achieved with a low ionic strength buffer solution with sucrose and ATP. Further purification is accomplished by a cycle of polymerization-depolymerization. This "brain actin" shares with muscle actin the following properties: (1) Similar molecular weight and molecular charge as determined by SDS polyacrylamide gel and ordinary disc electrophoresis; (2) Polymerization to a filamentous form under the same conditions; (3) Contains 3-methylhistidine; (4) Vinblastine sulfate will induce filament formation.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.