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Biomedical subjects

D Taylor

Publications and source records attributed to D Taylor.

At least 253 records · Page 14Linked to original sources
PubMed1995

Modulation of amblyopia therapy following early surgery for unilateral congenital cataracts.

BACKGROUND: Stimulus deprivation amblyopia is the principal cause of visual impairment in infants with unilateral congenital cataract. Even if lensectomy is undertaken at an early age, intensive postoperative occlusion of the phakic eye is essential for the development of useful vision in the aphakic eye. Despite this, the optimum method of regulating occlusion therapy is uncertain. METHODS: Interocular acuity differences identified using clinical preferential looking techniques (Keeler cards) were used to regulate target levels of phakic eye occlusion in a prospective evaluation of 10 systemically, metabolically, and neurologically normal infants in whom dense unilateral cataract was diagnosed before 8 weeks of age, and operated upon by 10 weeks. Actual occlusion levels were recorded each day by parents in a diary. The development of preferential looking acuity in the phakic and aphakic eye were compared with prediction intervals derived from observations on 43 normal children. RESULTS: Aphakic eye preferential looking acuities were within the normal range at last review in all but one infant. Interocular acuity differences were < or = 0.5 octave in all children older than 1 year of age at last review, and > or = 1 octave in three of four children less than 1 year old at last review (Fisher exact p = 0.033). Phakic eye acuities were within the normal range in all infants at all visits. CONCLUSION: Within the first 2 years of life, normal preferential looking acuity may be achieved in both eyes of infants undergoing early surgery for unilateral congenital cataract if occlusion therapy is modulated according to interocular acuity differences quantified by clinical preferential looking techniques.

Amblyopia↗
PubMed1995

Selective serotonin reuptake inhibitors and tricyclic antidepressants in combination. Interactions and therapeutic uses.

BACKGROUND: The selective serotonin reuptake inhibitors (SSRIs) are now widely used in the treatment of depressive illness. Interest has grown in the use of SSRIs as alternatives to tricyclic antidepressants (TCAs) and in the therapeutic use of combinations of SSRIs and TCAs in refractory depression. METHOD: MEDLINE and PSYCLit literature searches were conducted. Reference sections from papers retrieved were scrutinised for other relevant reports. RESULTS: Of 41 relevant articles identified, 35 were selected for review. CONCLUSIONS: Fluoxetine, fluvoxamine, paroxetine and sertraline may substantially increase TCA plasma levels when given concurrently. Such interactions may give rise to adverse effects. The effect of sertraline may be less profound than that of fluoxetine, fluvoxamine and paroxetine. Limited data suggest that citalopram may not affect TCA serum levels. There is scant literature evidence to support the use of SSRIs in combination with TCAs as a treatment for refractory depression.

Antidepressive Agents, Tricyclic↗
PubMed1994

The prescribing and adverse reactions of nonsteroidal antiinflammatory drugs in general practice: a Dunedin study.

AIMS: The aims of this study were to describe the prescribing of nonsteroidal antiinflammatory drugs (NSAIDs) by some general practitioners and to assess the information recorded on computer records on their use in individual patients so that techniques could be developed for a broader investigation of the topic in general practice. METHODS: All prescribing and consulting data from five Dunedin practices was reviewed for a 6 month period. From all consultations generating a prescription for NSAIDs, data was collected relating to the name of the drug, dosage, strength and length of treatment and patient demographic and morbidity details. Recorded adverse drug reactions were classified into six groups and four age groups were used for the analysis. RESULTS: Prescriptions for NSAIDs accounted for 2.6% of all items prescribed. Diclofenac was the most commonly prescribed NSAID, for most conditions, but menstrual problems were more likely to be treated with mefenamic acid. Coprescription of possibly contraindicated medications (usually antihypertensive medicines) occurred for 20.8% of patients. Gastric adverse reactions were reported in 3% of cases while 0.9% of prescriptions resulted in no change in condition, leading to a change in therapy. Aspirin, fenbufen, ketoprofen, sulindac and flurbiprofen were never prescribed for patients under 20 years old. CONCLUSION: Routinely recorded patient and prescribing information from general practice permits an assessment of the use of NSAIDs which includes the conditions for which they are prescribed, the total numbers prescribed, concurrent medications prescribed and their recorded adverse effects. This is not possible from any other source. Data from clinical trials provides an incomplete assessment of the use of these medications in general practice.

Adult↗
PubMed1994

Adenovirus-associated pneumonia and hepatitis in four llamas.

This report focuses on the diagnostic laboratory and necropsy findings in 4 llamas with adenovirus-associated hepatitis or pneumonia. In the 2 young llamas, clinical illness was characterized by chronic respiratory tract disease. In the 2 adult llamas, clinical illness was characterized by neurologic signs and a history of respiratory tract disease. Histologic examination, electron microscopy, virus isolation, and fluorescent antibody results indicated that adenovirus infection was associated with disease in all 4 llamas.

Adenoviridae↗
PubMed1994

Specific interaction of 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid with human cellular CD4.

We recently demonstrated that 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) prevented the infection of T cells by human immunodeficiency virus type-1 (Cardin et al., J. Biol. Chem. 266, 13355, 1991). In the present study we have used a panel of monoclonal antibodies (mabs) against a variety of human leukocyte antigens to characterize the interaction of DIDS by flow cytometry with various T cell surface molecules. DIDS blocked the specific immunoreactivity of mabs OKT4A and Leu 3A with CD4 on human leukemic T cells (JM) and human mononuclear lymphocytes with an IC50 approximately 30 microM. The membrane distal (D1) and proximal (D3 and D4) domains of CD4 remained blocked for up to 5 hr of culture and returned to control levels of expression after 24 hr, reflecting the rate of membrane turnover of the CD4-DIDS complex. The binding frequencies (% positive) for anti-CD2, -CD3, -CD5, -CD6, -CD7, -CD8, -CD11a, -CD14, -CD18, -CD19, -CD45, -T cell receptor, and -HLA-DR were not significantly affected. However, there was a partial reduction in the antigen density of CD2, CD5, CD8, and CD11b. The selective interaction of DIDS with CD4 suggests that antagonism of the virus receptor may account in part for the antiviral properties of the stilbene disulfonate.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1994

Airbag and facebag benefits and costs.

There is debate about the appropriate design of supplementary airbags for passenger car occupants with high levels of seatbelt use. A theoretical analysis was performed to demonstrate the likely costs and benefits of U.S. fullsize driver airbags and the smaller European-style facebag. This study, undertaken for the Federal Office of Road Safety in Australia, builds upon previous work in this area. Benefits were determined using Harm Reductions for front-seat occupants involved in frontal crashes. A sensitivity analysis was undertaken for different benefit scenarios for the facebag, given the lack of available performance data. Likely costs of the components were derived from information provided by the local automobile manufacturers, part suppliers, and vehicle importers, with adjustments made for fitting to Australian vehicles. The results demonstrate the advantage of fullsize airbags over facebags, even when seatbelt wearing rates are high.

Air Bags↗
PubMed1994

Prediction of bone adaptation using damage accumulation.

The adaptation of bones to a change in function has been recognised for many centuries, but only recently have mathematical laws been proposed to describe it. One proposed mathematical law is based on the hypothesis that, after a change in load, the strain in the bone microstructure is regulated to a homeostatic equilibrium. Strain-adaptive remodelling has been used successfully to simulate bone adaptation around orthopaedic implants but the predictive capabilities are constrained because many empirical constants are required in the remodelling law (a reference stimulus, a zone of equilibrium stresses or 'lazy zone' and a parameter transducing macroscopic stresses to a tissue level stimulus). An alternative approach has been proposed. It is that bone adapts to attain an optimal strength by regulating the damage generated in its microstructural elements. The question is raised whether or not a mathematical law to predict the time course of bone adaptation can be derived for damage-adaptive remodelling in a similar way to the mathematical laws based on a strain stimulus. In the present study, the hypotheses required to develop damage-adaptive remodelling laws are proposed and a remodelling law to predict the time course of bone adaptation is derived. It is shown that this is an integral remodelling law which accounts naturally for the stress history to which the tissue has been exposed since formation. A simulation of the adaptive response of a bone diaphysis under a change in torsional load shows that the law gives physically reasonable predictions. The initial remodelling prediction is similar to strain-adaptive remodelling. However, in the later stages of remodelling, the predictions differ from strain-adaptive remodelling in that direct convergence to a homeostatic strain is not predicted. Instead, undershoot (in the case of a reduction in load) and overshoot (in the case of an increase in load) are predicted.

Adaptation, Physiological↗
PubMed1994

Evaluation of experimental and finite element models of synthetic and cadaveric femora for pre-clinical design-analysis.

The aim of this study was to determine the validity with which the finite element method could model synthetic bone and thereby determine the appropriateness of such femur analogues for application in pre-clinical tests. The performance of these synthetic femora was compared with cadaveric bone when employing the same geometric and material definition protocols. A four-point bend loading configuration was selected for this analysis. Four synthetic femurs and an embalmed cadaveric bone were tested experimentally to determine the structural bending stiffness (k) for the diaphysis of these bones. A finite element (FE) model was generated and an analysis performed for each bone type to estimate the Young's modulus (E) required to obtain a model stiffness equivalent to that obtained experimentally. The estimated material elastic modulus in the FE model for the synthetic femur was found to be very similar to available data for this bone analogue. The estimated cadaveric bone modulus however was found to differ significantly from documented values for cortical bone. A theoretical analysis demonstrated the great sensitivity of the estimated modulus value to the accuracy of the geometric definition. The very low variability found in the experimental test on the synthetic bones together with their more regular geometry and the possibility of achieving greater accuracy in geometric definition was shown to enable the production of a valid FE model of this bone for an isotropic homogeneous material description. Conversely, the greater irregularity of geometry, together with the less obvious differentiation between the cortical and cancellous bone in the cadaveric specimen makes accurate geometric description of this bone very difficult. This fact, together with the uncertainty concerning the quality of the cadaveric bone and its viscoelastic response during mechanical testing, makes reproduction of its behaviour in a FE model a much more demanding task. It is suggested that this greater capability of reproducing the experimental behaviour of the synthetic bone makes them a very useful model for both experimental and numerical studies which involve in-vitro pre-clinical testing of implant design and stem-bone behaviour.

Artificial Organs↗
PubMed1994

Substance use among the mentally ill: prevalence, reasons for use, and effects on illness.

Substance use among a random sample of mentally ill, community-based patients was examined. Current use was found to have declined substantially from a high lifetime prevalence, and a family history of substance abuse was associated with moderate to heavy use. No association was found between heavy substance use and elevated psychopathology, hospitalization, or medication noncompliance. Hospital admissions and some symptoms were less prevalent among users preferring marijuana.

Adolescent↗
PubMed1994

Mutations at the PAX6 locus are found in heterogeneous anterior segment malformations including Peters' anomaly.

Mutation or deletion of the PAX6 gene underlies many cases of aniridia. Three lines of evidence now converge to implicate PAX6 more widely in anterior segment malformations including Peters' anomaly. First, a child with Peters' anomaly is deleted for one copy of PAX6. Second, affected members of a family with dominantly inherited anterior segment malformations, including Peters' anomaly are heterozygous for an R26G mutation in the PAX6 paired box. Third, a proportion of Sey/+ Smalleye mice, heterozygous for a nonsense mutation in murine Pax-6, have an ocular phenotype resembling Peters' anomaly. We therefore propose that a variety of anterior segment anomalies may be associated with PAX6 mutations.

Amino Acid Sequence↗
PubMed1994

The effect of glycerol monolaurate on growth of, and production of toxic shock syndrome toxin-1 and lipase by, Staphylococcus aureus.

The effects of glycerol monolaurate on the growth of, and production of Toxic Shock Syndrome Toxin-1 (TSST-1) and lipase by, Staphylococcus aureus FRI 1187 were investigated in batch and continuous culture models using a defined synthetic medium. The growth and yield of S. aureus depended on glycerol monolaurate concentration, pH of the environment and the inoculum size. The MICs for glycerol monolaurate of 29 S. aureus isolates, determined in a complex medium, were between 10 and 20 mg/L with a 10(3) to 10(4) cfu inoculum; a 1000-fold increase in inoculum size increased the MIC five-fold. In continuous culture, glycerol monolaurate increased the cell yield of S. aureus. In batch cultures with 17 mg/L glycerol monolaurate, TSST-1 and lipase production by S. aureus was delayed and their specific production was not decreased compared with cultures without glycerol monolaurate. At 150 mg/L glycerol monolaurate, growth and toxin production were decreased. The lipase of S. aureus hydrolyzed glycerol monolaurate. The reduction of toxin production was associated with effects on S. aureus growth, and these effects might have been relieved after lipase had been produced.

Bacterial Toxins↗