PubMed Health⌕ Search

Biomedical subjects

D M Taylor

Publications and source records attributed to D M Taylor.

At least 19 recordsLinked to original sources
PubMed1992

A surface plasmon resonance immunosensor based on the streptavidin-biotin complex.

It is shown that a streptavidin monolayer immobilized onto an evaporated gold film with biotin forms the basis of a highly specific sensing element. As an example, we show that by immobilizing the biotinylated antibody sex hormone binding globulin (alpha-SHBG) to the bound streptavidin monolayer a specific sensor for the antigen SHBG is readily fabricated. The interaction between immobilized antibody and corresponding antigen is monitored by surface plasmon resonance spectroscopy and is shown to follow a classic Langmuir isotherm. Detection of SHBG at nanomolar concentrations is demonstrated.

Antigens↗
PubMed1992

NSPEC: a chemical speciation program for personal computers.

The details of a computer program, NSPEC, which simulates chemical speciation in aqueous systems, are presented. NSPEC has been designed explicitly for the IBM PC family of computers and is a departure from normal speciation programs in that it is controlled through interaction with a series of menus. The program is more user-friendly than other comparable speciation programs, can write the results files in formats suitable for importing into other programs, and, in many instances gives results faster than speciation programs running on microcomputers.

Algorithms↗
PubMed1992

Bovine spongiform encephalopathy (BSE): a stimulus to wider research.

The severity of the epidemic of bovine spongiform encephalopathy which is currently afflicting cattle in the British Isles has stimulated a considerable research effort, much of which is directed toward understanding the aetiology and pathogenesis of the bovine disease. However, a significant thrust has also been orchestrated to address more fundamental issues such as the nature of the uncharacterized causal agents of the wider range of unusual animal and human diseases which share similar characteristics. The background to some of these research programmes is discussed, together with current aims and progress.

Animals↗
PubMed1991

Proton transport at the monolayer-water interface.

It is shown that when monolayers of stearic acid, palmitic acid, DPPC, or DPPS are compressed above some critical area Ac a lateral conduction mechanism is initiated at the monolayer/water interface. The interfacial conductance increases on further increasing the molecular packing density in the monolayer. All compounds also show major changes in surface potential at Ac the potential becoming more positive in all cases. It is argued that this is a consequence of structural reorganisation at the headgroup/water interface causing a significant reduction in the local permittivity. The critical area, Ac, is approximately double the molecular areas estimated from the pressure-area isotherm, and experiments with stearic acid monolayers show that Ac decreases significantly when the chaotropic ion SCN-, which is known to disrupt the molecular structure of water, is added to the subphase. It is likely, therefore, that the structural changes occurring at Ac involve the formation of a hydrogen bonded network between monolayer headgroups and adjacent water molecules at the monolayer/water interface. It is suggested that the conduction mechanism initiated at Ac arises from proton hopping along this hydrogen-bond network.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1991

Inactivation of the unconventional agents of scrapie, bovine spongiform encephalopathy and Creutzfeldt-Jakob disease.

Scrapie, bovine spongiform encephalopathy (BSE) and Creutzfeldt-Jakob disease (CJD) are the best known of the transmissible degenerative encephalopathies (TDE) that affect animals and man. Among the unusual properties of the unconventional causal agents is their relative resistance to standard decontamination procedures, and this has resulted in accidental transmission. Scrapie in sheep is the most common of these diseases and, through laboratory studies, is the best understood. As the model for the group, scrapie agent has been used in experiments to devise general standards for decontamination of the agents of the TDE.

Animals↗
PubMed1991

Resistance of the ME7 scrapie agent to peracetic acid.

Mouse brain infected with the ME7 strain of scrapie agent was exposed for 24 h to a range of concentrations of PAA, either as fragments of intact brain or as supernates of homogenised brain. Two % PAA inactivated the infectivity in intact tissue but not in a supernate. None of the concentrations tested (up to 19%) was effective with supernates, and this was considered to result from the protection afforded by aggregation of infectivity-containing particles.

Animals↗
PubMed1991

Effectiveness of DTPA treatments following the injection of particulate plutonium.

A limited long-term experiment has been completed in which the chronic toxicity resulting from a single intravenous injection of 31.4 kBq of a poly-disperse 239Pu colloid sol per kg of body weight was tested in Beagle dogs. The Pu deposited mostly in the phagocytic cells of liver, spleen and to a lesser degree in lung and bone marrow. Slow solubilization of the Pu particles by endogenous ligands caused translocation of the nuclide and redeposition mostly as monomeric Pu in the skeleton and in liver hepatocytes. Thus, the deposit behaved as expected from a pulmonary or wound contamination in humans with a moderately soluble depot of Pu such as Class W hot particles. Therefore, this type of deposit provided the basis for a practical model to study the ensuing radiation effects under various experimental conditions. The dogs were divided into three groups of four animals each, and the following conditions were applied: (a) no further treatment was given, allowing free translocation of the Pu to its secondary deposition sites; (b) interception of the Pu translocation by weekly injections of 30 mumol of Ca-DTPA/kg of body weight (Ca-chelate of diethylene-triaminepentaacetic acid); and (c) interception of translocation by daily injections of 30 mumol/kg body weight of Zn-DTPA. For each of the groups (b) and (c), three dogs were used in a lifetime study, and one was sacrificed for nuclide distribution studies. Free translocation and subsequent deposition in the skeleton resulted in the death of each of the non-chelated dogs from osteosarcoma between 1267 and 1594 days after injection. Weekly treatment with Ca-DTPA reduced the total Pu burden significantly, but these dogs also died with osteosarcoma between 1462 and 1783 days. Daily injections with Zn-DTPA reduced the total Pu burden more efficiently than Ca-DTPA and prevented continuous deposition of solubilized Pu on bone surfaces. The mean post-injection survival of these dogs was 3520 days or about 2.1 times that of the animals receiving Ca-DTPA, while the latent period for bone tumour induction was about 2.6 times longer. This treatment reduced the severity of liver lesions and eliminated the occurrence of persistent leukopenia, but it did not prevent the formation of bone cancer.

Animals↗
PubMed1991

Inactivation of BSE agent.

Although there are no data reported yet for inactivation of BSE agent it is reasonable in the interim, to draw upon existing data for other transmissible degenerative encephalopathies (TDE), much of which derives from experiments with the scrapie agent. Such studies suggest that no standard chemical or physical decontamination procedure will reliably inactivate the amount of scrapie/BSE infectivity present in worst-case situations but high concentrations of sodium hypochlorite or sodium hydroxide have been shown respectively to be completely effective or almost so. Regarding physical inactivation procedures, it is clear that some infectivity survives exposure to doses of UV and ionising radiations which represent "overkill" for conventional viruses. With dry heat, survival of infectivity is also remarkable, and it is only through autoclaving that apparently secure standards can be achieved for thermal inactivation; even so, autoclaving procedures need to be more rigorous than for conventional microorganisms, and can be compromised by prior chemical treatment of infected material.

Animals↗
PubMed1991

An aqueous paracentesis pipet.

We describe a glass pipet tipped with a short, sharp, 30-gauge needle for performing aqueous paracentesis. The design eliminates the possibility of needle bending and minimizes fractional resistance during limbus penetration; it also allows quicker recovery of aqueous samples. A small plastic bulb at the upper end facilitates removal of aqueous samples from the pipet.

Aqueous Humor↗
PubMed1990

A refractive and histopathologic study of excimer laser keratectomy in primates.

Using a 193-nm excimer laser, we produced wide-area, refractive keratectomies on 18 cynomolgus monkey corneas and followed them up for up to 18 months. All corneas developed some subepithelial haze by one month. Electron microscopy disclosed epithelial thickening, absence of Bowman's layer, and subepithelial activated fibroblasts surrounded by disorganized collagen. By six months, the haze faded to a variable degree, the epithelium regained normal thickness, and the collagen was more organized. Persistent corneal haze at 12 months in some corneas correlated with electronlucent spaces in the subepithelial zone. Corneas were 90 microns thinner centrally two weeks after myopic ablation, but returned to preoperative thickness by six months. Myopic flattening and hyperopic steepening of 6 diopters were targeted, and over 7 diopters of each were achieved initially. Regression of induced curvature stabilized over several months. At 18 months, 4.4 diopters of myopic flattening and 5.2 diopters of hyperopic steepening remained.

Animals↗