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Biomedical subjects

D M Taylor

Publications and source records attributed to D M Taylor.

At least 19 recordsLinked to original sources
PubMed2000

Closely similar values obtained when the ME7 strain of scrapie agent was titrated in parallel by two individuals in separate laboratories using two sublines of C57BL mice.

A single C57BL mouse-brain infected with the ME7 strain of mouse-passaged scrapie agent was used to carry out four parallel infectivity titrations in mice. These were carried out by two individuals in two laboratories using two sublines of C57BL mice. The titre values obtained by the four assays were very similar, and showed no significant differences between the two different operatives, the two different laboratories or the two different sublines of C57BL mice. The data confirm the validity of comparing these types of transmission data generated in different laboratories when a common methodology is used.

Animals↗
PubMed2000

Generic models for radionuclide dosimetry: 11C-, 18F- or 75Se-labelled amino acids.

A generic biokinetic model was developed for use in the assessment of the internal dose received by human subjects injected with amino acids labelled with 11C (T1/2 = 0.34 h, beta+, gamma), 18F(T1/2 = 1.83 h, beta+, gamma) or 75Se (T1/2 = 119.8 d, beta-, gamma). This generic model was used in conjunction with the MIRDOSE 3 computer programme to calculate radiation doses to adults; these radiation doses were compared with those calculated using compound-specific models for two [11C]-, and eight [18F]-labelled amino acids and [75Se]selenomethionine. In general, the effective doses, as well as the organ and tissue doses, calculated using the generic model agreed within a factor of 2 or less, with those calculated using compound-specific models; the generic model tended to over-, rather than underestimate the organ and tissue doses. It was concluded that for 11C- and 18F-labelled amino acids and for 75Se-labelled amino acids or their analogues, the single generic biokinetic model could be applied for general radiation protection purposes.

Adult↗
PubMed2000

Inactivation of transmissible degenerative encephalopathy agents: A review.

The unconventional agents that cause transmissible degenerative encephalopathies, such as bovine spongiform encephalopathy, scrapie, and Creutzfeldt-Jakob disease (CJD), are relatively resistant to inactivation by standard decontamination procedures. The only methods that appear to be completely effective under worst-case conditions are strong sodium hypochlorite solutions or hot solutions of sodium hydroxide. Other procedures that result in significant degrees of inactivation are described. The infectivity levels in histologically-fixed tissue can be reduced substantially by treatment with concentrated formic acid without adversely affecting the microscopic quality of the tissue.

Animals↗
PubMed2000

Discharge instructions for emergency department patients: what should we provide?

Effective communication between the physician and patient is required for optimum post-emergency department management. Written emergency department discharge instructions, when used to complement verbal instructions, have been shown to improve communication and patient management. This review examines the purpose, advantages, and disadvantages of three commonly used types of discharge instruction. The desirable features of discharge instructions are described. It is recommended that structured, pre-formatted instruction sheets be provided to all patients discharged to home, that emergency departments establish uniform policies to promote best practice in communication, and that the use of discharge instructions be considered as an emergency department performance indicator.

Communication↗
PubMed2000

Emergency department discharge instructions: a wide variation in practice across Australasia.

OBJECTIVES: All patients discharged from the emergency department (ED) should be given discharge instructions (DIs). This study aimed to describe the DI practices of EDs in Australasia and to examine the differences between public and private EDs. METHODS: A voluntary, questionnaire-based survey of public and private EDs throughout Australia and New Zealand. RESULTS: 58 of 74 (78.4%) EDs provided instruction notes upon discharge although 51 (68.9%) gave them to only "some" patients. There were no significant differences between the public and private EDs (p>0.05). Thirty seven (50%) EDs provided pre-formatted instruction sheets although 22 (29.7%) EDs gave them to only "some" patients. There were no significant differences between the public and private EDs (p>0.05). Only five (6.8%) EDs retained a copy of the instruction sheets and no (O%) ED provided sheets that included all recommended features. Sixty six (89.2%) EDs provided information sheets although 44 (59.5%) EDs gave them to only "some" patients. Private EDs gave information sheets to significantly more patients than public EDs (p=0.04). CONCLUSIONS: The DI practices of individual EDs varied and the rates of DI provision were low. EDs should improve their DI practices. Pre-formatted instruction sheets, containing all recommended features, should be provided to all patients with a copy kept in the medical record. Consideration should be given to the use of DI practices as an ED performance indicator.

Australia↗
PubMed1999

Survival of scrapie agent after exposure to sodium dodecyl sulphate and heat.

Fifty mg aliquots of macerated mouse-brain infected with the 22A strain of scrapie agent were treated by exposing them without mechanical mixing to (a) distilled water for 2 h, (b) 5% sodium dodecyl sulphate (SDS) for 2 h, (c) autoclaving at 121 degrees C for 15 min in distilled water, (d) autoclaving at 121 degrees C for 15 min in 5% SDS, or (e) boiling in 5% SDS for 15 min. Prior to injection into mice, all samples were washed by a procedure that is described and was shown not to reduce infectivity titres. Although the infectivity titre of the sample that was autoclaved in SDS was reduced considerably, infectivity was present in all of the samples exposed to cold or hot SDS.

Animals↗
PubMed1999

Successful preimplantation genetic diagnosis for sex Link Lesch--Nyhan Syndrome using specific diagnosis.

Lesch-Nyhan syndrome (LN) is a severe X-linked recessive disorder caused by a deficiency of the enzyme hypoxanthine phosphoribosyl transferase (HRT). Clinical features displayed by affected boys are particularly severe and disturbing and include hyperuricaemia, Characteristic neurological features including self-mutilation, choreothetosis, spasticity and mental retardation. A couple with a boy diagnosed with LN and a history of pregnancy termination was referred to the Hammersmith Hospital. Their affected son was born in 1982 after an uncomplicated pregnancy and vaginal delivery. Eight subsequent pregnancies had been unsuccessful. There were five therapeutic terminations and three spontaneous abortions, one at least directly caused by the sampling procedure during amniocentesis. From 1989 to 1991 two unsuccessful preimplantation genetic diagnosis (PGD) cycles by sexing were performed by DNA amplification. The mutation was characterized and a nested PCR protocol was designed which allowed the efficient amplification of the affected loci followed by the detection of the mutant allele by restriction digestion. Three PGD cycles were performed using this specific diagnostic test before a successful pregnancy was achieved resulting in the birth of a healthy unaffected baby girl.

Embryo Transfer↗
PubMed1999

Inactivation of prions by physical and chemical means.

Prions are very resistant to inactivation, and accidental transmission has occurred through the use of inadequate decontamination procedures. Strong sodium hypochiorite solutions achieve inactivation but other chlorine-releasing compounds are less effective. 2M sodium hydroxide leads to substantial but incomplete inactivation; other chemical procedures such as the use of proprietary phenolic disinfectants are much less less effective. Infectivity can survive autoclaving at 132-138 degrees C, and under certain conditions the effectiveness of autoclaving actually declines as the temperature is increased. The small resistant subpopulations that survive autoclaving are not inactivated by simply re-autoclaving, and they acquire biological characteristics that differentiate them from the main population. Despite the limitations of autoclaving, combining autoclaving (even at 121 degrees C) with a sodium hydroxide treatment is extremely effective. Protein-fixation (e.g., by ethanol or formalin) substantially enhances the thermostability of these agents. This suggests that future successful inactivation strategies might best be developed by studying procedures that avoid protein-fixation.

Animals↗
PubMed1999

Continuously recorded suckling behaviour and its effect on lactational amenorrhoea.

The hypothesis that the month-specific rate of return to ovarian cyclicity after childbirth is causally related to suckling pattern was tested for a population of New Mexican women recruited within the service area of New Mexico Highlands University and for a nationwide USA subpopulation of women recruited through membership of the Couple to Couple League (CCL). Survival analysis for time-dependent covariates was used, and significant predictors of the first postpartum menses were found. Important differences were detected in the suckling pattern for the two groups and a 5:2 differential was found in their respective rates of menstrual cycle recovery. Although the two groups were comparable perinatally, daily and time-windowed breast-feeding performance fell off at twice the rate for the New Mexico population when contrasted with the CCL sample. For both populations, the introduction of solid feeds was a strong and significant predictor of returning menstrual cyclicity, independent of suckling pattern.

Adult↗
PubMed1999

Halothane, but not the nonimmobilizers perfluoropentane and 1,2-dichlorohexafluorocyclobutane, depresses synaptic transmission in hippocampal CA1 neurons in rats.

UNLABELLED: Volatile anesthetics may decrease synaptic transmission at central neurons by presynaptic and/or postsynaptic actions. Nonimmobilizers are volatile compounds with lipophilicities that suggest that they should (but do not) prevent motor responses to surgical stimuli. However, nonimmobilizers interfere with learning and memory, and, thus, might be predicted to depress synaptic transmission in areas of the brain mediating memory (e.g., hippocampal CA1 neurons). To test this possibility, we stimulated the Schaffer collaterals of rat hippocampal slices and recorded from stratum pyramidale of CA1 neurons. At approximately 0.5 MAC (MAC is the minimum alveolar anesthetic concentration at one standard atmosphere that is required to eliminate movement in response to noxious stimulation in 50% of subjects), halothane decreased population spike amplitude 37% +/- 21% (mean +/- SD), increased latency 15% +/- 9%, and decreased excitatory postsynaptic potentials 16% +/- 10%. In contrast, at concentrations below (0.4 times) predicted MAC, the nonimmobilizer, 1,2 dichlorohexafluorocyclobutane (2N), slightly (not significantly) increased population spike amplitude, decreased population spike latency 9% +/- 4%, and increased excitatory postsynaptic potentials 22% +/- 16%. At concentrations above (2 times) predicted MAC, 2N did not significantly increase population spike, decreased latency 10% +/- 4%, and did not significantly change excitatory postsynaptic potentials. At 0.1 predicted MAC, a second nonimmobilizer, perfluoropentane, tended (P = 0.05) to increase (11% +/- 9%) population spike amplitude, decreased population spike latency 8% +/- 2%, and tended (P = 0.06) to increase excitatory postsynaptic potentials (9% +/- 8%). We conclude that clinically relevant concentrations of halothane depress synaptic transmission at Schaffer collateral-CA1 synapses and that the nonimmobilizers 2N and perfluoropentane have no effect or are excitatory. The Schaffer collateral-CA1 synapse may serve as a useful model for the production of immobility by volatile anesthetics, but is flawed as a model for the capacity of volatile anesthetics to interfere with memory and learning. IMPLICATIONS: Halothane, but not the nonimmobilizers 1,2-dichlorohexafluorocyclobutane and perfluoropentane, inhibits hippocampal synaptic transmission at Schaffer collateral-CA1 synapses.

Action Potentials↗
PubMed1999

A comparison of Australasian and United States emergency medicine training programs.

Training programs in emergency medicine differ from country to country. This article compares the allopathic training programs of Australasia and the United States. The perceived advantages of these programs are highlighted, but no attempt is made to determine which is the better program. The Australasian program is significantly longer and places a greater emphasis on the basic clinical sciences, physical examination skills, and academic output. Australasian College for Emergency Medicine (ACEM) regulations are relatively flexible and allow trainees to design their own programs. Trainees are encouraged to arrange accredited positions in a variety of hospitals. Overseas and part-time training may be acceptable. In the United States, trainees rotate within and from one parent institution, which provides a rigid teaching structure for a "critical mass" of trainees, based on a "core" curriculum. Rotations tend to be much shorter but ensure exposure to a broader range of clinical experience. Evaluation of trainees and teaching faculty is more frequent and documentation of procedural and resuscitation skills is required. Trainees are under the close supervision of teaching faculty at all times when working in an ED.

Accreditation↗
PubMed1999

Current outpatient management of asthma shows poor compliance with International Consensus Guidelines.

STUDY OBJECTIVE: This study aimed to establish whether the outpatient management of patients presenting with an asthma exacerbation to the emergency department (ED) was in compliance with the 1992 guidelines of the "International Consensus Report on the Diagnosis and Management of Asthma." DESIGN: Prospective, observational study using a researcher-administered questionnaire. SETTING: University tertiary referral ED. PATIENTS: Convenience sample of asthmatics (aged 18 to 54 years) presenting for asthma treatment between July 1, 1997, and June 30, 1998. RESULTS: Eighty-five asthmatic patients were enrolled. Of these, 34 patients (40%) smoked, 53 patients (62%) were undertreated with medication when compared to the consensus guidelines, and 74 patients (87%) had no written "plan of action." During an asthma attack, 9 patients (11%) did not use a bronchodilator as first-line action and 76 patients (89%) did not commence or increase the use of an inhaled steroid. Forty-nine patients (58%) did not know that bronchospasm occurred in asthma, and 53 patients (62%) did not know that bronchial swelling occurred. Twenty-six patients (31%) thought short-acting bronchodilator drugs were asthma preventers. Sixty-two patients (73%) could not adequately define peak expiratory flow (PF), 41 patients (48%) did not own a PF meter, and only 8 patients (9%) determined their PF daily. Fifty-three patients (62%) were reviewed by a physician once a year or less, and 18 patients (21%) noted family and friends as their only source of asthma education. CONCLUSIONS: The outpatient management of most asthma patients presenting to the ED did not comply with the consensus guidelines, and asthma knowledge was poor.

Adolescent↗
PubMed1999

The fibrinogen gamma chain dodecapeptide inhibits agonist-induced aggregation of rabbit platelets and fibrinogen binding to rabbit glycoprotein IIb-IIIa.

The HHLGGAKQAGDV (H12) sequence at the carboxyl termini of the y chains and the RGD sequences in the Aalpha chains of human fibrinogen are potential recognition sites for the binding of soluble fibrinogen to glycoprotein IIb-IIIa (GPIIb-IIIa) on activated human platelets. Thus, addition of either H12 or RGD-containing peptides inhibits aggregation of and fibrinogen binding to human platelets. In contrast, we reported previously that RGDS had relatively little inhibitory effect on these functions of rabbit platelets. In the present study, we found that H12 inhibited ADP- and thrombin-induced aggregation of rabbit platelets in a dose-dependent manner. Specificity was demonstrated by the failure of the variant HHLGGAKQAGEV peptide to inhibit ADP-induced aggregation. Furthermore, flow cytometric analyses demonstrated that H12 inhibited the binding of FITC-fibrinogen to ADP-activated rabbit platelets in a dose-dependent manner. To examine the direct interaction of H12 with rabbit GPIIb-IIIa, we performed affinity chromatography by applying an octylglucoside extract of rabbit platelet proteins onto an affinity matrix containing the fibrinogen gamma chain sequence. Proteins of approximately 135 kDa and approximately 95 kDa were specifically eluted by soluble H12, and the 95 kDa protein band was immunoblotted by anti-LIBS1, a monoclonal antibody against human GPIIIa. In control samples, no detectable protein from rabbit platelet lysates was eluted from an RGD affinity matrix by GRGDSP. Collectively, our results demonstrated that H12 inhibits aggregation of and fibrinogen binding to rabbit platelets by directly interacting with rabbit GPIIb-IIIa. These findings suggest that rabbit platelets would serve as a suitable thrombosis model for testing the efficacy of peptide mimetics derived from H12.

Animals↗
PubMed1999

An analysis of the demand for and cost of preimplantation genetic diagnosis in the United Kingdom.

Research in the field of preimplantation genetic diagnosis (PGD) has concentrated on increasing the number of diseases diagnosed, different strategies for single cell analysis and improving efficiency and reliability. Of equal importance are clinical issues such as the demand for and cost of PGD. This study assesses patient awareness of PGD and its potential benefits; additionally the awareness, attitudes and referral patterns of Assisted Conception Units, Regional Genetics Centres and Health Authorities (funding bodies) have been analysed to establish the demand for PGD within the United Kingdom. The licensed units are able to perform 128 cycles of PGD annually, however 256 cases were referred within the last year. It is clear that the currently licensed units operating at their present capacity are unable to meet the demand for PGD in the U.K. Concerns raised by this study include the unequal geographical distribution of PGD services and the lack of a uniform funding policy by Health Authorities. The investment in personnel and technology to establish a PGD service is considered and a costing provided. We estimate an initial investment in the region of 139,000 Pounds with annual running costs of 55,000 Pounds. This information should contribute towards an appropriate allocation of resources at a national level in the U.K.

Awareness↗
PubMed1998

Solvent extraction as an adjunct to rendering: the effect on BSE and scrapie agents of hot solvents followed by dry heat and steam.

The study was designed to determine the effect on bovine spongiform encephalopathy (BSE) and scrapie agents of the solvent extraction processes used in the past by British renderers. The raw material was mouse spleen infected with either the 22A strain of scrapie agent or the 301V strain of BSE agent. Samples were exposed to hexane, heptane, petroleum spirit or perchlorethylene at the relevant temperatures for the appropriate times. Control samples were exposed to the same range of temperatures for the same range of times in saline. Other samples were exposed to the hot solvents, followed by treatment with dry heat at 100 degrees C for 30 minutes and steam at 100 degrees C for 30 minutes. Further samples were exposed only to the dry heat and steam cycles. No single complete process was significantly more effective than any of the others, and they all produced only slight inactivation, less than one log on average for both strains of agent. The average degree of inactivation produced by exposure to hot saline was generally comparable to that produced by exposure to the hot solvents. This was also true for the samples exposed only to dry heat and steam compared with those exposed to hot solvent before treatment with dry heat and steam, and suggests that the slight inactivation was caused by the heat rather than by the solvents. It is concluded that the solvent extraction processes used by renderers in Britain had little capacity to inactivate BSE and scrapie agents.

Abattoirs↗