Every woman with an abnormal cervical smear should not be referred for colposcopy: debate.
Explore the source record for details and available documents.
Colposcopy↗
Biomedical subjects
P Walker
Publications and source records attributed to P Walker.
Experience with ACS for infantile SGS.
Explore the source record for details and available documents.
Humans↗
Impairment of diastolic function during short-term anthracycline chemotherapy.
OBJECTIVE: To assess the early changes in left ventricular diastolic and systolic function due to anthracycline treatment. DESIGN: A prospective study of cardiac function by radionuclide angiography in adults before and one month after the end of anthracycline treatment. PATIENTS: 60 patients without cardiac disease treated with chemotherapy containing anthracycline. METHODS: Cardiac function was assessed by radionuclide measurement throughout treatment. Ejection fraction, peak ejection rate, time to peak ejection rate, filling rate, and time to peak filling rate were measured before and after treatment. To normalise radionuclide measurements of the left ventricular diastolic function the ratio of the filling rate to the ejection fraction and the ratio of the filling rate to the peak ejection rate were calculated. RESULTS: No patient developed symptomatic congestive cardiac failure. The ejection fraction decreased from 58% (5%) to 55% (6%) (P < 0.001), the peak ejection rate fell from 2.99 (0.41) to 2.77 (0.41) of the end diastolic volume per second (P < 0.001), and the peak filling rate from 2.71 (0.47) to 2.55 (0.44) of the end diastolic volume per second (P < 0.01) after treatment. No difference was observed in the normalised ratios. CONCLUSIONS: This report shows simultaneous impairment of left ventricular systolic and diastolic radionuclide parameters. The absence of variation in normalised measurements suggests similar changes in ejection fraction, peak ejection rate, and peak filling rate throughout treatment.
Adult↗
Two types of representation in visual memory: evidence from the effects of stimulus contrast on image combination.
An imagery task was used to explore the distinction between visual memory representations that preserve surface features and more abstract descriptions. Subjects were shown two line drawings and were then asked to combine a visual image of each drawing in order to identify a novel figure. The main experimental manipulation concerned the contrast in which each drawing was shown, which was either normal or reversed. Experiment 1 showed that image combination was more efficient when the contrasts of the two drawings were congruent with each other, but only when the imagery task was performed under conditions emphasizing short-term memory (STM). There was no effect of congruity when one of the images was generated from long-term memory (LTM). These results are consistent with the idea that the surface characteristics of a stimulus are preserved in visual STM, but a more abstract description is stored in visual LTM. In Experiment 2 we explored the influence of verbal recoding on performance of the imagery task by requiring subjects to suppress articulation. Under LTM conditions, performance of the imagery task was improved by suppression and became sensitive to contrast congruity. Under STM conditions, imagery was unaffected by suppression. Overall, these results support the distinction between surface and abstract descriptions in visual memory. However, they suggest that this distinction does not map onto that between STM and LTM in any simple way. It is suggested that short-term visual memory maintains surface descriptions and long-term visual memory preserves both surface and abstract descriptions. Verbal coding of visual stimuli appears to encourage the use of abstract visual descriptions.
Adolescent↗
Ligand binding analysis of human neuropeptide Y1 receptor mutants expressed in E. coli.
Site-directed mutants of the human neuropeptide Y1 (NPY Y1) receptor expressed as a maltose binding protein fusion protein in E. coli show identical ligand binding parameters compared with the same mutants expressed in mammalian cells using a vaccinia virus expression system. However, it was remarkable that two receptor mutants, which were initially classified as non-binding when expressed in an eukaryotic expression system, could actually be revealed to have wild-type binding activity when expressed in E. coli. Re-expression and retesting of these mutants in mammalian cells confirmed this result. This shows that bacterial expression can be used as a fast, versatile and valuable alternative to mammalian expression systems for the analysis of ligand binding sites in G-protein coupled receptors.
ATP-Binding Cassette Transporters↗
Interactions between NPY and its receptor: assessment using ant-NPY antibodies.
The present data show that monoclonal antibodies (NPY02, NPY03, NPY04, NPY05) directed against 4 distinct epitopes on NPY may have different actions on NPY binding and NPY-induced cellular responses. NPY02 and NPY05 recognize the 11-24 and 32-36 amidated form of NPY, respectively. These 2 antibodies block the binding of NPY to its receptor as well as the NPY-induced inhibition of cAMP accumulation caused in SK-N-MC cells by forskolin. NPY02 and NPY05 have also an inhibitory action on NPY-induced contraction of rabbit femoral arteries. NPY03 and NPY04 are directed against the 27-34 and 1-12 part of NPY, respectively. NPY03 and NPY04 inhibit the binding of NPY only at very high concentrations and have a weak effect on cAMP response to NPY. NPY02 and NPY05 might provide useful tools to study the effect of NPY in cellular systems and organ preparations.
Amino Acid Sequence↗
Finding black holes in numerical spacetimes.
Explore the source record for details and available documents.
Journal Article↗
Acidic residues in extracellular loops of the human Y1 neuropeptide Y receptor are essential for ligand binding.
To investigate whether negatively charged residues of the human Y1 neuropeptide Y (NPY) receptor are required for ligand binding, a series of mutants were constructed in which aspartic acid and glutamic acid residues present in putative extracellular domains of the Y1 receptor were systematically replaced by alanines. The mutant cDNAs were transiently expressed in HeLa cells using a vaccinia virus-derived expression system, and their ability to bind NPY was evaluated. The level of expression of mutants unable to bind NPY was also tested immunologically. In addition, the ability of the mutant proteins to be recruited to the cell surface was assessed by confocal microscopy. Substitution of aspartic acids and glutamic acids of the N-terminal first extracellular domain had no effect on binding. On the other hand, substitution of acidic residues present in the second, third, and fourth extracellular loops resulted in proteins unable to bind 125I-NPY. These results demonstrate that the extracellular loops of the human Y1 NPY receptor are essential portions of its ligand binding domain.
Amino Acid Sequence↗
Word repetition effects on event-related potentials in healthy young and old subjects, and in patients with Alzheimer-type dementia.
Event-related potentials (ERPs) were recorded from 16 healthy young (mean age 21 years) and 16 healthy old subjects (mean age 64 years), and from 11 subjects with a diagnosis of Dementia of Alzheimer Type (DAT). The task requirement was to attend to a series of visually presented words so as to respond to occasional animal names. Non-animal names repeated after either a single or six intervening items. In the young subjects ERPs evoked by repeated words displayed a widespread, sustained positive-going shift relative to ERPs evoked by first presentations (the ERP repetition effect). This effect onset around 220 msec and did not differ as a function of inter-item lag. Other than for a delay in onset of approximately 80 msec, the ERP repetition effect in the healthy old group was in all respects equivalent to that of the young subjects. The ERP repetition effects in the DAT patients were statistically indistinguishable from those of an appropriately matched sub-set of the healthy old subjects. These results indicate that the ERP repetition effect remains robust in subjects in whom explicit memory has declined as a result of normal aging or DAT. Thus they suggest that the effect reflects processes independent of those underlying explicit memory, and that it may index a form of memory relatively unaffected by the pathology underlying DAT.
Adolescent↗
The enhanced representation of surface texture consequent on the loss of sight.
The unitisation effect in probed feature-recall was exploited to reveal changes in the representation of objects consequent on the loss of sight. Blind and sighted adults were given verbal descriptions of simple objects and later recalled the colour and surface texture of each object. While the blind and sighted were equally capable of recalling an object's colour, the blind were more capable than the sighted at recalling its surface texture. The superior recall of surface texture by the blind emerged very gradually as an increasing percentage of their lifetime was spent without sight. It is concluded that features salient for the haptic sense are increasingly likely to be incorporated in the blind person's representation of objects.
Adolescent↗
Aortic valve disease in patients with Wegener's granulomatosis.
Wegener's granulomatosis usually affects the upper and lower respiratory tract as well as the kidney. Cardiac involvement is rare, although electrocardiographic abnormalities, coronary artery vasculitis, cardiac arrhythmias, and myocardial infarction have been described. We report two cases of aortic valve disease associated with Wegener's granulomatosis that were progressive despite clinical remission of Wegener's disease in both patients. One patient has undergone successful valve replacement and the other is currently awaiting surgery. Aortic valve histopathology showed myxoid degeneration that was most likely due to previously active vasculitis affecting the vessels of the aortic wall and valvular necrosis with subsequent progressive degeneration of the cusps.
Adult↗
Preliminary observations of metabolic characterization of bilateral temporal epileptic focus, using proton magnetic resonance spectroscopy. Three cases.
The authors report the case of 3 patients with bilateral temporal lobe epilepsy demonstrated by EEG and sphenoïdal electrodes. Two out of the 3 patients presented with childhood febrile convulsions. Their neurological and mental examination was normal. EEG showed spikes within the anterior part of the 2 temporal lobes. CT scan and MRI showed no atrophic lesion within the 2 temporal lobes. Proton magnetic resonance spectroscopy, performed within a cube of 8 cube-centimetres localized in the anterior part of the 2 temporal lobes showed a significant decrease of N-acetyl-aspartate in the 2 temporal lobes of the 3 cases, compared with controls matched with age, sex and laterality. Because N-acetyl-aspartate is a marker of the neuronal cells, the decreased level of NAA in the temporal area with spikes, may be related to a decreased number of neuronal cells, developing an abnormal tendency to seizures.
Adolescent↗
Developing the communication skills of tomorrow's minority physicians.
Explore the source record for details and available documents.
Communication↗
The prevalence of specific arithmetic difficulties and specific reading difficulties in 9- to 10-year-old boys and girls.
Data from an epidemiological sample (n = 1206) of British schoolchildren were used to estimate the proportions of 9- to 10-year-olds with specific arithmetic difficulties (SAD), combined with arithmetic-and-reading difficulties (ARD), and specific reading difficulties (SRD). Children in the sample contributed scores on separate tests of arithmetic, reading and nonverbal intelligence. Using a cutting-score approach, which took into account performance on all three tests, a small group of children with SAD (1.3%) were distinguished from larger groups with ARD (2.3%) and SRD (3.9%). Contrary to some previous reports, there were equal numbers of males and females within each of the two groups with arithmetic difficulties but a preponderance of males over females amongst the group with specific reading difficulties.
Child↗
Phosphorus magnetic resonance spectroscopy: a noninvasive technique for the study of occlusive arterial leg disease and peripheral vasodilator therapy.
Using 31P nuclear magnetic resonance spectroscopy of the calf muscle, the authors studied patients with peripheral arterial occlusive disease. They studied PCr depletion and intracellular pH during aerobic exercise in patients and controls. The phosphocreatine (PCr) index ([PCr]/([PCr] + [Pi])) at rest was correlated with blood flow measured by plethysmography. During aerobic exercise a greater decrease in pH was obtained in patients (p < 0.03). They also studied the work necessary to reach a PCr index = 0.5 during ischemic exercise. This workload was lower in patients than in controls: 32.99 +/- 3.04 J vs 58.89 +/- 8.55 J, p < 0.05. After vasodilator therapy the workload was improved in patients: 32.99 +/- 3.04 J vs 38.85 +/- 3.54 J, p < 0.05. These results suggest that therapy resulted in improved tissue perfusion in patients.
Arterial Occlusive Diseases↗
[Effect of rehabilitation after myocardial infarction on muscular metabolism. Contribution of phosphorus 31 NMR spectroscopy].
P 31 NMR spectroscopy is a recent technique which allows a non-invasive and direct analysis of oxidative metabolism and pH changes, an indicator of acidosis due to lactic acid accumulation in the skeletal muscles. The authors investigated oxidative muscular metabolism of the sural triceps in 10 patients after myocardial infarction by performing a study after the acute phase and repeating the study after a programme of physical training. At rest, there were no significant differences. On the other hand, for the same level of maximal effort, the depletion in phosphocreatinine (PCr) and the accumulation of inorganic phosphate (Pi) were significantly lower after physical training: the PCr/PCr + Pi increased from 0.467 +/- 0.179 to 0.538 +/- 0.20 (p < 0.02) and the Pi/PCr ratio decreased from 1.570 +/- 1.440 to 1.181 +/- 1.069 (p < 0.05). The pH at the same level of maximal exercise did not change significantly between the two periods: 6.85 +/- 0.16 vs 6.88 +/- 0.15 (NS). The peak oxygen consumption (VO2) measured during bicycle ergometry increased significantly from 23.4 +/- 10.5 to 28.3 +/- 12.14 ml/min/kg after exercise training (p < 0.01). In addition, a correlation was observed between the improvement of the peripheral parameters (PCr/PCr + Pi) and the increase in VO2 max (r = 0.757, p < 0.01). The authors results confirm the effects of physical training on oxidative metabolisms of the peripheral muscles and its influence on improvement of global performance of coronary patients.
Adult↗
Demystifying the research process in education.
A well-developed base of empirical research is essential for accountable midwifery practice. Midwives need to develop 'research confidence'. The research process is explained sequentially from identification of the research problem, through literature review, research design, methodology, data collection and analysis. Research will enable the midwifery profession to develop further by uncovering the knowledge embedded in practice and in the education and management of midwives.
Data Interpretation, Statistical↗
Electrocautery-induced ignition of tonsillar packing.
A recent case of ignition of a bismuth-subgallate pack during routine tonsillectomy prompted this investigation of local oxygen levels. Similar conditions were reproduced in the laboratory to determine their influence on the flammability of materials commonly used to aid in haemostasis. Cotton tonsil packs soaked in saline, adrenalin, or adrenalin and bismuth were compared. During spontaneous ventilation through an age-appropriate uncuffed endotracheal tube, an air leak rarely occurred. However, when assisted ventilation was used, an airway leak produced an elevated oxygen concentration in 8 of 10 children. This was associated with increased combustibility of the packs, regardless of solution mixture. The addition of bismuth further increased combustibility. Partially saturated packs appeared to be more combustible than fully saturated packs.
Child↗