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Biomedical subjects

D Taylor

Publications and source records attributed to D Taylor.

At least 361 records · Page 20Linked to original sources
PubMed1990

Stress analysis of the proximo-medial femur after total hip replacement.

Stress-induced bone loss in the proximo-medial femur has been identified as a factor leading to loosening in the artificial hip joint. In an effort to develop a quantitative understanding of the stress distribution that causes bone loss, axial and hoop stresses in the medial calcar of the femur have been determined after total hip replacement, using finite element stress analysis. Stress distributions for a high and a low Young's modulus prosthesis material are compared for both collared and uncollared prosthesis designs. The use of a low-modulus material, and of a collar, are predicted to be advantageous, giving rise to proximo-medial stress patterns similar to those of the normal, intact femur.

Biomechanical Phenomena↗
PubMed1990

Prior long term glycaemic control and insulin therapy in insulin-dependent diabetic adolescents with microalbuminuria.

Adolescence seems to be a period of increased risk for the initiation of diabetic renal disease in insulin-dependent diabetic children. Poor glycaemic control is a risk factor for diabetic nephropathy. We have therefore evaluated prior long-term glycaemic control in 23 diabetic adolescents with microalbuminuria (albumin excretion rate (AER) 20-200 micrograms/min, median 39.0 micrograms/min) and in 23 matched diabetic controls with AER less than 20 micrograms/min (median 9.3 micrograms/min). Glycaemic control was assessed by mean HbA1 and clinic blood glucose levels over a period ranging from 12 to 84 months (median 48 months). Mean HbA1 was 13.6 +/- 2.0% in the microalbuminuric subjects, compared to 11.5 +/- 2.2% in the controls (P less than 0.002); mean blood glucose levels were 13.5 +/- 3.0 and 11.4 +/- 3.0 mmol/l, respectively (P less than 0.02). There appeared to be a 'threshold effect' (mean HbA1 greater than 12.0%), above which the development of microalbuminuria was more likely. More patients with microalbuminuria than controls had been treated with a single rather than twice-daily insulin injections (P less than 0.001), and glycaemic control was significantly worse in patients treated with one injection. We conclude that poor long term glycaemic control is a risk factor for microalbuminuria, and that improving control during childhood is likely to reduce the prevalence of later microalbuminuria. Two insulin injections, of combined intermediate and short-acting preparations, are more likely to provide better control than a single daily insulin dose.

Adolescent↗
PubMed1990

The prevalence of micro-albuminuria and glomerular hyperfiltration in young patients with IDDM.

We have assessed the prevalence of two risk factors for diabetic nephropathy, i.e., micro-albuminuria and a raised glomerular filtration rate (GFR), in 127 insulin-dependent diabetic patients aged 13-36 years. Micro-albuminuria (albumin excretion rate (AER) 20-200 micrograms/min) was found in 46 subjects (36%) and GFR was elevated (greater than 135 ml/min/1.73 m2) in 43 (34%). The prevalence of supranormal GFR declined and that of micro-albuminuria rose progressively with the increasing duration of diabetes. While age and sex distribution were similar in subjects with and without raised AER, duration of diabetes was significantly longer, blood pressure (BP) was significantly greater and age of onset was lower in the micro-albuminuria group. Blood pressure was significantly elevated only in the patients with AER of 70-200 micrograms/min; there was a linear trend for BP to rise as AER increased. Stepwise logistic regression analysis indicated that duration of diabetes (P less than 0.0001), age of onset of diabetes (P less than 0.005) and current glycaemic control (HbA1) (P less than 0.01) were risk factors for micro-albuminuria. The association with a rising blood pressure appears to be secondary to the renal involvement. In this cross-sectional study an association of micro-albuminuria with a raised GFR could not be demonstrated.

Adult↗
PubMed1990

The effect of bacterial products on human fibroblast and keratinocyte detachment and viability.

An in vitro model has been developed to study the effect of soluble bacterial products on the viability and detachment of skin cell types utilized cultured grafts. Microbial products prepared from clinical isolates of bacterial species which most commonly colonize burn lesions showed marked variation in their ability to detach and kill both keratinocytes and fibroblasts. All three isolates of Acinetobacter spp. tested were effective in causing detachment and death of keratinocytes and fibroblasts, whereas Escherichia coli, Proteus mirabilis and Enterobacter spp. tested had little, or no, effect on detachment or viability for either skin cell type. Four Staphylococcus aureus isolates elicited variable strain-dependent results with regard to detachment and viability. One isolate possessed activity specific for keratinocyte detachment and death. These results indicate the possible undesirable effects such bacterial species may have on graft success in colonized burn wounds.

Bacteria↗
PubMed1990

Detection of isolated occipital lobe anomalies during early childhood.

The authors report two children with isolated occipital lobe anomalies detected by visual evoked potentials (VEPs) and confirmed by MRI and CT scanning. Both had a markedly asymmetrical occipital distribution of flash and pattern VEPs. One child had acuity reduced to 6/36, and testing on confrontation suggested an homonymous hemianopia. The second child was visually inattentive to one side during infancy. Neither child had band atrophy of the optic disc or an afferent pupillary defect. Isolated abnormalities of the occipital lobes are difficult to detect by clinical examination during infancy and early childhood. Recording VEPs from a horizontal array of occipital electrodes can be helpful in detecting subtle occipital lobe abnormalities.

Child↗
PubMed1990

The iris in Williams syndrome.

Forty three children with Williams syndrome and 124 control subjects had their eyes photographed. The photographs were examined by three ophthalmologists and four geneticists of varying experience. A stellate pattern was noted more often in the irides of patients with Williams syndrome (51%) than in those of the control subjects (12%), and was more difficult to detect, or was absent, in heavily pigmented irides. We conclude that the stellate pattern is of diagnostic importance, particularly if the pattern is carefully defined and the clinician is experienced.

Aortic Valve Stenosis↗
PubMed1990

Lens surgery in infancy and childhood.

The medical records of 224 children who had lens surgery performed at the Hospital for Sick Children during the 10-year period 1978-88 were reviewed. There were 12 children with ectopia lentis; these patients achieved a mean postoperative acuity of 0.68 (6/8.8), and no operative or postoperative complications were noted. Two hundred and twelve children had lens surgery for cataracts or for retrolental abnormalities with a clear lens. Children with bilateral congenital cataracts achieved a mean acuity in the better eye of 0.32 (6/18). In a series of carefully controlled unilateral congenital cataracts the visual results were poor. The postoperative complication rate for cataract and clear lens surgery was 4.6%. Because visual results are probably better with early surgery we emphasise that every newborn baby should be tested for media opacities.

Cataract↗
PubMed1990

Contact lenses for infant aphakia.

We prospectively studied for three years the optical correction by contact lenses of 83 aphakic infants (141 eyes) who generally also had systemic and other ocular anomalies: 85% of the patients tolerated the lens wear for the whole study period. Complications occurred in 46 eyes and led to cessation of lens wear in two cases. Ten patients abandoned the lenses for other reasons. Thirty-four eyes needed subsequent intraocular surgery, mostly minor, and nine patients had strabismus surgery. Contact lenses are a versatile, safe, successful, and cost effective treatment for aphakia in infancy against which, before their widespread introduction for primary optical correction of infant aphakia, other methods of aphakic treatment need to be compared.

Aphakia↗
PubMed1990

Time-series analysis. Use of autocorrelation as an analytic strategy for describing pattern and change.

Although graphic representation of time-series data is one method to describe patterns of phenomena, autocorrelations, correlograms, and plots of the autocorrelation function provide descriptive and statistical methods that reveal the structure of a deterministic cycle component within the time-series. The autocorrelation function provides a method for the investigator to test hypotheses about the nature and pattern of relationships between measured and latent variables. Patterns of phenomena can be analyzed statistically using objectively provided criteria. The autocorrelation function can also be used to understand the change in response or behavioral patterns following an experimental intervention. Traditional group comparison designs, using cross-sectional data collection strategies cannot identify differences within the individual nor can they identify patterns of behavior or structural patterns within the data. Autocorrelation and cross-correlation become threats to statistical validity when conventional methods are used; however, in time-series analysis, autocorrelation allows close scrutiny of the pattern of response within an individual across a time-dimension.

Data Interpretation, Statistical↗
PubMed1990

Psychoanalysis.

Explore the source record for details and available documents.

Adaptation, Psychological↗
PubMed1990

Childhood albinism. Visual electrophysiological features.

Flash ERGs and VEPs, and VEPs to pattern onset and pattern reversal stimulation were recorded in young albino children and compared to age-matched, normally pigmented, controls. In albinos, the ERG had a significantly larger a-wave, and significantly shorter latencies for both the a-wave and b-wave. VEPs to flash, pattern onset and pattern reversal stimulation all showed an occipital crossed asymmetry when comparing responses from each eye. However, the findings for flash stimulation were more consistent and reliable than those to either form of pattern stimulation.

Albinism, Ocular↗
PubMed1990

The pathology of human cerebral malaria.

Blockage of the cerebral microvasculature by Plasmodium falciparum-infected erythrocytes appears to be the principal cause of human cerebral malaria. Knobs which appear on the membrane of the infected erythrocytes adhere to the endothelium, causing the obstruction of cerebral microvessels. Protein molecules such as CD36, thrombospondin, and intercellular adhesion molecule-1, which are present on the membrane of endothelial cells, may act as receptors for the attachment of knobs of P. falciparum-infected erythrocytes. Each of these candidate host molecules for infected-cell recognition and attachment are expressed in microvessels of the human brain. The presence of HRP1 and HRP2 in the cerebral microvessels of cerebral malaria patients may indicate the involvement of knob proteins in the pathogenesis of cerebral malaria. Owl monkeys infected with P. falciparum do not develop cerebral malaria. There is no blockage of cerebral microvessels by infected erythrocytes and knob proteins are absent. These findings support the contention that cerebral microvessel blockage and the presence of knob proteins are the probable causes of cerebral malaria.

Animals↗
PubMed1990

Anti-CD3 antibody-induced expression of both p55 and p75 chains of the high affinity interleukin-2 receptor on human T lymphocytes is inhibited by cyclosporin A.

The inhibitory effect of cyclosporin (CsA) was investigated on human lymphocytes stimulated by anti-T-cell antibodies (anti-CD3 and -CD2) or mitogenic lectins. Whereas inhibition of cell proliferation (50%) occurred at 10 ng/ml CsA after cell activation via CD3 or CD2, higher CsA concentrations (300 ng/ml) were necessary to inhibit lectin-mediated cell activation (PHA, Con A). Exogenous recombinant interleukin-2 (rIL-2) partially reversed the inhibitory effect on antibody-stimulated cells only; however, at higher CsA concentrations (300 ng/ml) proliferation was again inhibited. Thus, CsA affected IL-2R expression and/or function at higher concentrations (300 ng/ml). CsA had no effect on receptor function as measured on IL-2-dependent cell growth of CTLL cells or preactivated lymphocytes. However, CsA inhibited both high and low affinity receptor expression as shown by [125I]IL-2 equilibrium binding studies on anti-CD3-stimulated cells. Cross-linking studies revealed that both p55 (TAC) and p75 chains of the IL-2R were not induced at low CsA concentrations (10 ng/ml). However, addition of rIL-2 reversed CsA inhibition of IL-2R expression. It is concluded that CsA, at least in anti-CD3-stimulated cells, inhibits IL-2R expression and cell proliferation with similar potency. Exogenous rIL-2 reverses CsA inhibition of IL-2R expression. This might be due to binding of rIL-2 to receptors which escape CsA inhibition, thereby up-regulating receptor expression which is drug resistant.

Antibodies, Monoclonal↗