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Biomedical subjects

A Atkin

Publications and source records attributed to A Atkin.

At least 19 recordsLinked to original sources
PubMed1998

Implementing the British Thoracic Society's guidelines: the effect of a nurse-run asthma clinic on prescribed treatment in an English general practice.

The advent of computer-based prescribing in general practice has made it possible to study a patient's drug use in detail. This study compared the use of inhaled therapy in 100 patients with chronic disease by examining every prescription issued during the year before and the year after initial consultation at a nurse-run asthma clinic. The majority were poorly controlled in that 79% scored high on the Jones Morbidity Index at their first visit. The number of patients on inhaled corticosteroid and salmeterol xinafoate rose from 87 to 100% and 6 to 28%, respectively, while those instructed to take their beta-agonist 'when required' as opposed to a regular dose rose from 26 to 82%. The daily median intake of short-acting beta-agonist fell from 5.0 to 3.8 doses (P < 0.0001). In the 87 patients on inhaled corticosteroid throughout, the mean daily dose increased from 532.1 to 793.1 micrograms (P < 0.0001), and compliance (defined as the total dose issued in 1 year expressed as a percentage of that recommended) increased from 61.5 to 69.3% (P = < 0.05). Attendance at a nurse-run asthma clinic was associated with a number of significant alterations in inhaled therapy. These changes conformed to the British Thoracic Society's guidelines.

Adolescent↗
PubMed1997

Reducing asthma morbidity in the community: the effect of a targeted nurse-run asthma clinic in an English general practice.

Although most primary health care teams in the U.K. now offer proactive care for patients with asthma, there is relatively little published evidence showing the effectiveness of such innovations. This may be due in part to lack of targeting of extra care towards those most in need. Therefore, to demonstrate the benefits of targeted nurse-run asthma clinic care in a seven-partner general practice in a mixed urban and rural area of North Lincolnshire in the east of England, a cohort of 173 patients, with asthma selected predominantly by having high morbidity in a postal survey, completed 12 months follow-up in a nurse-run asthma clinic. A longitudinal comparison was conducted in terms of: changes in morbidity index category, inhaler technique score, knowledge score, use of inhaled steroids, use of salmeterol, method of administration of beta(2)-agonist medication and frequent use of peak flow meters. The number with high morbidity fell from 123 (71.1%) at the initial consultation to 14 (8.1%) at the 12-month review. Those with full marks on inhaler technique rose from 28 (16.2%) to 142 (82.1%), and with full marks on asthma knowledge rose from 7 (4.0%) to 98 (56.6%). The numbers of patients using inhaled steroids and salmeterol rose from 127 (73.4%) to 171 (98.9%) and from 5 (2.9%) to 35 (20.2%), respectively. The preferred inhaler device for beta(2)-bronchodilator medication changed from metered dose aerosol to dry powder. Regular use of peak flow meters in 157 subjects aged 5 years and over rose from 43 (27.4%) to 116 (73.9%). These data clearly demonstrate the benefits of targeted proactive nurse-run asthma care in terms of reduced morbidity for patients. The authors recommend the morbidity index targeting concept to other primary health care teams.

Adolescent↗
PubMed1996

In vivo gene electroinjection and expression in rat liver.

In vivo targeted gene transfer by non-viral vectors is subjected to anatomical constraints depending on the route of administration. Transfection efficiency and gene expression in vivo using non-viral vectors is also relatively low. We report that in vivo electropermeabilization of the liver tissue of rats in the presence of genes encoding luciferase or beta-galactosidase resulted in the strong expression of these genetic markers in rat liver cells. About 30-40% of the rat liver cells electroporated expressed the beta-galactosidase genetic marker 48 h after electroporation. The marker expression was also detected at least 21 days after transfection at about 5% of the level 48 h after electroporation. The results indicate that gene transfer by electroporation in vivo may avoid anatomical constraints and low transfection efficiency.

Animals↗
PubMed1993

Phylogenetic and serological characterization of two Ugandan HIV-1 isolates.

HIV-1 isolates Ug06 and Ug23 were established in culture from peripheral blood mononuclear cells (PBMCs) of Ugandan subjects. The isolates were studied for phylogenetic and serological relationships with each other and with the laboratory strains, HTLV-IIIB and HIV-1MN. The results suggest that the Ugandan isolates are related to different subgroups of African viruses with 17.3% of genetic distance between UG06 and the U455 provirus (Uganda); and 12.6% of genetic distance between UG23 and the JY1 provirus (Zaire). Analysis of the predicted amino acid sequences for Ug06 and Ug23 showed marked sequence heterogeneity in the V3 region and CD4-binding site. A conserved amino acid sequence was identified in the C-terminal immunodominant region of the envelope glycoprotein gp120. The isolates were compared in virus-neutralization experiments with HTLV-IIIB and HIV-1MN stocks, using panels of Western blot-positive North American and Ugandan sera. The North American serum samples showed broad neutralizing activity against both of the Ugandan isolates. However, the Ugandan serum panel demonstrated strain-specific activity against either Ug06 or Ug23. Furthermore, the African serum specimens showed higher prevalence and titers of neutralizing activity against the HIV-1MN stock as compared with HTLV-IIIB.

Amino Acid Sequence↗
PubMed1993

Independent divergences in the CD4 binding site and V3 loop encoded in two seroprevalent Ugandan HIV-1 clinical isolates.

Two major epitopes expressed in HIV-1 have been recently shown to play a central role in virus neutralization. One of these important specificities is a type-specific or group-specific, principal neutralizing determinant (PND) located in the V3 loop of gp120. The other is a more broadly neutralizing determinant associated with the CD4 binding site. Structural and serological studies of the variation in these epitopes have become important in vaccine research. This report describes the analysis of the DNA clones encoding a region of gp120 that overlaps the V3 loop and the putative CD4 recognition site in two new African isolates, UG06c and UG23c. Phylogenetic analyses of the DNA sequences showed that the new African isolates clustered with two very distinct subtypes of HIV-1. UG06c was grouped with U455, D687, and Z321, previously classified as "HIV-1 subtype A" in the AIDS and human retroviruses database; and UG23c was grouped with MAL, JY1, NDK, ELI, and Z2Z6 classified as "HIV-1 subtype D." Considerable variation was apparent in the V3 loop. The divergence included the presence of the hexapeptides GP-GRSF and GLGQAL at the cap of the loop in UG06c and UG23c, respectively. The GPGR tetrapeptide in UG06c formed a beta-turn configuration similar to that of MN or IIIB. The beta-turn was not found to be a likely conformation for GLGQ. The amino acids previously implicated in CD4 binding and the associated neutralizing activity were relatively conserved. To assess a possible impact of the sequence and conformational variations on serological reactivity, UG06c and UG23c were subjected to neutralization assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

On consciousness: what is the role of emergence?

Can consciousness be understood as the ongoing active creation of information (of meaning)? 'Emergence', the central concept in this hypothesis, plays an essentially different role in it than in theories previously proposed.

Brain↗
PubMed1987

Potential ocular damage from microwave exposure during electrosurgery: dosimetric survey.

A dosimetric survey of microwave radiation emitted by electrosurgical units used in operating rooms indicated that surgeons expose themselves to levels that may be hazardous, and that ocular exposures are especially high: 20 cm from the active lead, electric field strength at the eye/forehead position was 9.0 X 10(6) V2/M2 for the monopolar unit; and magnetic field strength at this position reached a magnitude of 3.5 A2/M2. These electric and magnetic fields exceeded the TLVs of the American National Standards Institute. The authors concluded that the high levels of microwave radiation generated by electrosurgery devices should receive immediate attention to assess health effects associated with such exposures.

Electrocoagulation↗
PubMed1986

Radial keratotomy and glare effects on contrast sensitivity.

After radial keratotomy (RK) to correct myopia, some patients complain of 'glare'. Effects of a glare source on contrast sensitivity were measured in fifteen patients after unilateral RK. With each eye, determinations were made of the contrast required for detection of steady gratings (spatial frequencies of 0.7 and 2.9 cycles/deg), and for detection of flicker (unpatterned field flickering at rates of 8, 16, and 32 Hz). Grating or flicker was presented on a centrally fixated 4 deg test target (34 cd/m2 mean luminance), surrounded by a diffuse glare source (1700 cd/m2 mean luminance). For each stimulus, contrast thresholds were determined with glare-source off and with glare-source on. 'Glare loss' was defined as the decrement in contrast sensitivity measured with the glare source on. Significant findings were: (1) Both eyes showed glare losses for detection of gratings and for detection of flicker; (2) Spectacle lenses increased glare losses both for gratings and for flicker; (3) The RK eye showed a larger glare loss for flicker than the unoperated eye, but a smaller glare-loss for gratings; (4) For both flicker and gratings, glare loss tended to be greater in the RK eye, compared to the unoperated eye, in subjects who had larger pupil diameters in the testing situation; (5) The psychophysical measurements obtained in this study were not significantly correlated either with a questionnaire index of glare complaints or with the score obtained with the Miller-Nadler GlareTester.

Adult↗
PubMed1985

How might demyelinating disorders and glaucoma modify synaptic function?

Latencies of visually evoked potentials (VEPs) tend to be abnormally long in multiple sclerosis (MS). Similar VEP delays are seen in glaucoma. Such delays could result in part from reduced intensities of synaptic inputs at post-retinal synaptic relays, and defects of axoplasmic transport might be one cause for this. The effective rate of synaptic activation of a given postsynaptic neuron can be decreased either by reducing the arrival-rate of presynaptic action potentials (e.g., by complete or partial blockage of conduction in some presynaptic axons), or by reducing the quantity of neurotransmitter released per action potential (e.g., as a consequence of presynaptic neurotransmitter depletion). It is proposed that in both glaucoma and MS, delayed VEPs may result from either or both of these mechanisms. Firstly, loss and functional impairment of optic nerve axons occurs in each disorder. Secondly, in glaucoma the increased intraocular pressure tends to block the rapid anterograde axoplasmic transport (RAAT) which brings neurotransmitter supplies to the axon terminals. This could result in neurotransmitter depletion in the lateral geniculate relay, decreased synaptic effectiveness of remaining normally-conducting optic nerve axons, and thereby increased VEP latencies. RAAT is also blocked by demyelinated lesions that have been produced experimentally by injection of diphtheria toxin. If it is impaired by the demyelinated plaques of multiple sclerosis, then VEP slowing by a similar presynaptic depletion mechanism could ensue.

Brain↗
PubMed1983

Organicity and mental retardation: organic mental syndrome battery.

Fifteen mentally retarded children were tested and compared to 10 normal school children. They were administered a battery of tests reflecting organic brain disease, consisting of the Face-Hand, Midline Crossing and Independent Eye Movements Tests. Normals performed correctly 98% of the time on the three combined tests, while the mentally retarded scored only 34% correct. There was a significant correlation between IQ and this battery of tests (the 'OMSB'). When the IQ and OMSB were conflicting, a repeat of the former indicated that the IQ value was erroneous. The OMSB may be useful along with IQ testing as a rapid screening method to evaluate the presence of organicity and its severity.

Adolescent↗
PubMed1983

Flicker threshold and pattern VEP latency in ocular hypertension and glaucoma.

Latency of the pattern visual-evoked potential (PVEP) was measured in 24 ocular hypertensive (OHT) patients, eight open-angle glaucoma (OAG) patients, and 37 control subjects. The PVEP stimulus was a 2.3 cycle/degree sinusoidal grating, counterphase-modulated at 1 Hz. Field size was 9 degrees and mean luminance 1.7 log ft-lamberts. For 22 of the 32 patients, a psycholphysical measure of dynamic contrast sensitivity at 8 Hz (DRC) was obtained with a 4 degrees diameter stimulus, by determining the mean value for the contrast sensitivities to a homogeneous flickering field and to a 1.2 cycle/degree counterphase-flickering grating. Patient DRC values were compared with previously published control data from 21 subjects. Mean PVEP latencies of both the OHT and the OAG patients were greater than normal (P less than 0.001), with the OAG value larger than the OHT value (P less than 0.001). Mean DRCs were lower than normal (P less than 0.002) for both patient groups, with the OAG value lower than the OHT value (P less than 0.025). DRC correlated with PVEP latency for these patients (r = -0.66, P less than 0.001).

Evoked Potentials, Visual↗
PubMed1981

Organicity and mental retardation: analysis of eye and head movements.

Eye and head movements of ten mentally retarded (MR) children and ten normal school children were recorded. Each was directed to look to one side or the other in response to verbal commands, to gestural directions, or to the appearance of illuminated fixation targets. Under these conditions: 1. Large gaze movements of MR subjects were accompanied by head movements more frequently than those of the normal subjects. Furthermore, for similar gaze deviations, head movement of MR subjects tended to be larger than those of normal subjects. 2. Head movements of normal subjects rarely began before eye movement, but those of MR subjects often did so. This "abnormal" MR eye-head movement pattern was more frequent in response to verbal or gestural commands than in response elicited by illumination of fixation targets.

Child↗
PubMed1981

Saccades of hyperactive and normal boys during ocular pursuit.

Eye movements of hyperactive and normal boys were compared on a visual pursuit task in three experiments. In the first series of tests, irregular pursuit occurred more often in hyperactive than in normal boys. Hyperactive boys made more saccadic movements, their average saccades were larger, and they looked away from the pursuit path more frequently than the normal boys. In a second series of tests three years later, the differences between normal and hyperactive boys still existed. In a third set of experiments the effects of an attention task, different stimulus velocities and stimulant medication were studied in another group of control and hyperactive boys. With or without the attention task, hyperactive boys not receiving stimulant medication made more saccades than normal boys. Differences were greatest at lower target velocities and decreased at higher stimulus velocities. Differences between hyperactive and normal boys disappeared when the former received both stimulant medication and the attention task. The findings were the same in the two groups of hyperactive boys: they had more saccades superimposed on ocular pursuit than did normal boys. Differences between the groups may be related to their relative ability to attend to the target. The differences are of a magnitude that might make them useful as an adjunct for diagnosis of hyperactivity or for evaluating the effects of treatment.

Adaptation, Physiological↗
PubMed1980

Contrast sensitivity in retinal disease.

Central vision in patients with retinal disorders has been studied with sinusoidal grating patterns. Impaired detection of fine high-contrast gratings has been observed in patients with retinitis pigmentosa and glaucoma despite 20/20 vision. Abnormal contrast sensitivity to coarse gratings occurred in patients with certain macular disorders and occasional glaucoma patients, some with near-normal Snellen acuity. Thus, contrast sensitivity measurements demonstrate central visual deficits not apparent with Snellen testing.

Glaucoma↗
PubMed1980

Interocular comparison of contrast sensitivities in glaucoma patients and suspects.

Glaucoma affected the ability to detect low-contrast, flickering patterns ('DRC' measurement). DRC patterns were foveally viewed, of low spatial frequency, and flickering at 8 hertz. Interocular comparisons were performed in control subjects, in ocular hypertensives, and in glaucoma patients with asymmetric damage. Interocular differences in DRC tended to be of greater magnitude in the glaucoma patients than in the ocular hypertensive patients or control subjects. In the glaucoma patients DRC was consistently lower in the eye with the greater field defect than in the other (more normal) eye. In patients with optic disc asymmetry DRC was lower in the eye with the more abnormal disc. Treatment asymmetries did not appear to play a significant role in these relationships. When examined by interocular comparisons DRC showed no consistent relationship to Snellen visual acuity or to level of intraocular pressure at the time of DRC testing.

Form Perception↗
PubMed1979

The ocular manifestations and functional effects of occupational argyrosis.

Thirty employees of an industrial plant involved in the manufacture of silver nitrate and silver oxide underwent ophthalmologic evaluation in an effort to evaluate the frequency and extent of ocular argyrosis. The most frequently noted ocular abnormality was pigmentation of the conjunctiva, present in 20 workers; corneal pigmentation occurred in 15 workers. A direct relationship existed between the levels of pigmentation and duration of employment. Ocular pigmentation was seen more frequently than cutaneous pigmentation. Ten workers noted decreased night vision, but electrophysiologic and psychophysiologic studies of seven of these ten workers demonstrated no functional deficits.

Adult↗
PubMed1979

Abnormalities of central contrast sensitivity in glaucoma.

The detectability of foveally presented low-contrast flickering stimuli was determined for glaucoma patients, ocular hypertensives, and normal control subjects. Two types of stimuli, a homogeneous flickering field, and a counterphase flickering grating of low spatial frequency, were presented on a screen subtending 4 degrees of visual angle. The average of the contrast sensitivities to these two simuli (defined as the dynamic response coefficient) was consistently lower in glaucomatous than in normotensive eyes. The dynamic response coefficient was also below normal in half the ocular hypertensive eyes.

Adult↗