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Biomedical subjects

A J Phillips

Publications and source records attributed to A J Phillips.

At least 37 records · Page 2Linked to original sources
PubMed1997

Nuclear magnetic resonance characterization of 6 alpha-chloro-5 beta-cholestane-3 beta,5-diol formed from the reaction of hypochlorous acid with cholesterol.

Hypochlorous acid generated by neutrophil myeloperoxidase has been shown to convert cholesterol into three different chlorohydrin isomers which previously had not been fully characterized. We have reacted hypochlorous acid with cholesterol/1,2-dipalmitoyl phosphatidylcholine liposomes to give these three major products and established that they are 6 beta-chloro-5 alpha-cholestane-3 beta,5-diol (chlorohydrin 1), 5 alpha-chloro-6 beta-cholestane-3,6-diol (chlorohydrin 2) and 6 alpha-chloro-5 beta-cholestane-3 beta,5-diol (chlorohydrin 3). These products were separated by thin-layer chromatography and fully characterized by 1H, 13C, attached proton test, doublequantum correlation spectroscopy, total correlation spectroscopy, heteronuclear multiple bond correlation and heteronuclear multiple quantum coherence nuclear magnetic resonance spectroscopy.

Cholestanols↗
PubMed1996

Effects of feeding, watering and resting intervals on lambs transported by road and ferry to France.

Three lorry loads, each of approximately 530 lambs, were monitored during August 1994 while they were transported from the Midlands to France. Each lorry underwent a similar journey, designed to study the effects of a) 22 hours on a lorry broken by two hours of feed, water and rest after 15 hours, b) 34 hours on a lorry broken by eight hours of feed, water and rest after 24 hours and c) 24 hours on a lorry and lairage for the following 48 hours. Measurements were made on 180 lambs in each load, of liveweight, plasma betahydroxybutyrate (BHB), non-esterified fatty acids (NEFA), urea, total protein, albumin, osmolality, creatine kinase (CK), cortisol and glucose, before, during and after transport. Twenty-four hours of transport resulted in changes in some of the variables measured that were little different from those observed after 24 hours of feed and water deprivation; however, the high ambient temperatures during the transport resulted in a greater degree of dehydration. For journeys longer than 15 hours a two-hour rest in lairage with access to water and a palatable food source was beneficial in allowing some slight recovery. Although all the differences were in the direction that would be expected with recovery, they were often small and, within the sensitivity of the study, were only significant for NEFA and C.K. For journeys longer than 24 hours, an eight-hour rest in lairage with access to water and a palatable food source was beneficial and allowed material realimentation and rehydration before further transport for up to 10 hours. After 24 hours of transport, however, liveweight, plasma urea, total protein and albumin had only returned to basal levels after 24 hours in lairage and plasma BHB, CK and osmolality after 48 hours of lairage.

3-Hydroxybutyric Acid↗
PubMed1996

Otoacoustic emissions recorded at high rates in patients with confirmed acoustic neuromas.

Otoacoustic emission testing was carried out on 39 patients with confirmed acoustic neuromas, and satisfactory emissions were recorded from the neuroma ear of 59% of them. A comparison of the patients with and without emissions showed no significant differences in low-frequency or high-frequency hearing loss, optimum speech discrimination score, or canal paresis in the affected ear between the two groups. Emissions were recorded at stimulus rates up to 5,000 clicks/s by using the maximum length sequence (MLS) technique. The decrease in the emission amplitude with increase in click rate (rate suppression) was significantly less than the amount that would be expected from normal subjects for several of the neuroma patients. However, one patient showed normal suppression despite having a large neuroma and no measurable hearing. This would suggest that efferent suppression may not be the only mechanism involved.

Acoustic Stimulation↗
PubMed1995

Effects on sheep of transport by road for up to 24 hours.

Five groups of 20 slaughter sheep of approximately 37.9 kg liveweight were transported by road for either three, nine, 15, 18 or 24 hours and three groups were not transported, one of them being deprived of food and water for 24 hours. Before and after transport the liveweight and various blood variables were measured and heart rate and behavioural observations were recorded from subsets of the animals. With increased journey time there was a decrease in liveweight and an increase in the plasma levels of free fatty acids, beta-hydroxybutyrate and urea; however, the changes over 24 hours were similar to those in the group deprived of food and water. In the transported sheep, the heart rate and levels of plasma cortisol and glucose were increased by the stresses of loading and the initial stages of the journey, but after nine hours the sheep appeared, to some extent, to have adapted. They were able to lie down and did not appear to be physically stressed. Measurements of plasma osmolality, total plasma protein and albumin did not indicate that the sheep had become severely dehydrated after 24 hours of transport but upon their return, feeding and drinking activity was greater than that observed before the journey.

Adaptation, Physiological↗
PubMed1995

Effects on cattle of transport by road for up to 15 hours.

Twenty-four castrated male cattle aged between 12 and 18 months were transported by road for five, 10 or 15 hours, over distances of 286, 536 and 738 km. Half the animals were of Hereford x Friesian breeding and half of 'continental' type. The animals transported for five hours lost 4.6 per cent of their bodyweight, those transported for 10 hours lost 6.5 per cent and those transported for 15 hours lost 7.0 per cent; recovery to pre-transport values took five days. There was little evidence from changes in blood composition that a 15-hour journey was more stressful than a 10-hour journey. The cortisol concentrations were increased by the stresses of loading and the first part of the journey but then recovered as the journey continued. Creatine phosphokinase (CPK) activities increased progressively with the longer journeys and CPK, urea, albumin and osmolality levels recovered more slowly after the longer journeys. Increases in free fatty acids, beta-hydroxybutyrate and urea concentrations and the continued increase in urea levels after the end of the journeys suggested that the animals' normal pattern of feeding was disrupted. Increases in albumin, total plasma protein and osmolality indicated slight dehydration during transit which was quickly rectified by access to water. The two breed types responded similarly to transport, except that the increases in CPK were greater in the continental breeds, possibly as a result of their greater muscularity or greater sensitivity to stress. Based on the physiological measurements made and the subjective observations of behaviour a 15-hour transport period under good conditions is not unacceptable from the viewpoint of animal welfare.

Animal Husbandry↗
PubMed1995

The effect of different concentrations of mannitol in solution on small intestinal transit: implications for drug absorption.

The aim of the present study was to investigate the effect that different concentrations of mannitol have on small intestinal transit, and whether any observed effect was concentration dependent. Eight, healthy male subjects each received 200ml of radiolabelled purified water, or a 200ml solution of mannitol at three different concentrations; 0.755g/200ml, 1.509g/200ml and 2.264g/200ml, in a randomised, four way cross-over study. Transit of the radiolabelled solutions was followed by gamma scintigraphy. The study demonstrated no significant differences between the gastric emptying times of the four solutions. Rapid gastric emptying was observed in most cases. The mean small intestinal transit times for the 0.755g/200ml, 1.509g/200ml and 2.264g/200ml mannitol solutions was reduced by 11%, 23% and 34% respectively, when compared to the control solution. The intestinal transit data of the four solutions demonstrate that mannitol has a concentration dependent effect on small intestinal transit. Small concentrations of mannitol included in a pharmaceutical formulation could therefore lead to reduced uptake with any drug exclusively absorbed from the small intestine.

Adult↗
PubMed1995

The effects of pharmaceutical excipients on small intestinal transit.

1. The effect of three iso-osmotic pharmaceutical excipient solutions on gastrointestinal transit were investigated in eight healthy male volunteers. Each subject received 200 ml radiolabelled purified water, or a 200 ml solution of sodium acid pyrophosphate ((SAPP) 1.1 g/200 ml), mannitol (2.264 g/200 ml) or sucrose (4.08 g/200 ml) in a four way cross over design. On each of the study days the volunteers also received five 6 mm diameter non-disintegrating tablets. Dual isotope gamma scintigraphy was used to assess the transit behaviour of the tablets and solutions. 2. There were no significant differences between the gastric emptying times of the four solution formulations. Rapid gastric emptying was observed in all cases (mean t 50% varied from 11-14 min). 3. Small intestinal transit (SIT) times for the SAPP and mannitol solutions were reduced by 39 and 34%, respectively, when compared with the control solution (purified water = 240 min; SAPP = 147 min; mannitol = 158 min). The 95% confidence limits for the mean differences in SIT time between the control and SAPP solutions was 39-94-149 min, and 40-82-124 min between the mannitol and the control. Intestinal transit for the sucrose solution was similar to that for the control solution (sucrose = 229 min). 4. There were no significant differences in the transit times of the non-disintegrating tablet preparations, when co-administered with each solution.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Isochronic mapping of the auditory brainstem response: normative results.

Isochronic mapping involves recording multi-channel evoked potentials from scalp electrodes and plotting contours of peak latencies. In this study, auditory brainstem responses were recorded from 20 electrode sites for left, right and binaural stimulation of each ear of 10 male and 10 female, normally hearing, young adults. Analysis of the data showed that the stimulus parameters of intensity, polarity and rate had no significant effect on the maps. On monaural stimulation, wave V was recorded first at the contralateral mastoid and ipsilaterally frontally and last at the ipsilateral mastoid some 350, mu s later. Binaural stimulation gave a symmetrical map, with wave V recorded first frontally and last at the occiput. In contrast, wave III was recorded first ipsilaterally and frontally and last at the contralateral mastoid. Wave II was recorded first at the rear of the contralateral mastoid and last forward of the ipsilateral mastoid. Comparisons between these results and human physiological studies are in agreement for waves V and III but do not support the concept of the VIIth nerve alone as the generator for wave II. These results suggest that this technique is a potentially useful diagnostic tool and it is intended to evaluate it by testing patients with a range of sensory, peripheral-neural and central-neural pathologies.

Audiometry, Pure-Tone↗
PubMed1994

Experience of using vibrotactile aids with the profoundly deafened.

This is a summary of clinical experience and research findings gathered from using vibrotactile aids over 7 years. This interest grew from a research project to evaluate four wrist-worn vibrotactile aids for the rehabilitation of the profoundly deaf. To facilitate this, a training programme was developed to help patients get the most from the aid. Having found that the RNID/Summit Tam vibrotactile aid was the most appropriate, this has been fitted to over 50 patients. The results of the comparative trial, an evaluation of our methods and a discussion of our clinical experience using vibrotactile aids with profoundly deafened patients are presented.

Deafness↗
PubMed1993

Managed-care pharmacy: an integrated MIS approach.

Administering a managed-care pharmacy means data, data and more data. Drug interactions, duplicate therapy and early refills need to be pinpointed. M Technology fills that prescription with ease.

Clinical Pharmacy Information Systems↗
PubMed1992

The effect of posture on three objective audiological measures.

This study examines the effect of posture on click evoked otoacoustic emissions, tympanic membrane displacement, and travelling wave velocity obtained using the auditory brainstem response. Statistically significant changes with posture were observed for each technique. The changes in evoked emission and tympanic membrane displacement measurements were comparable with those reported by previous experiments. Travelling wave velocity measurements were shown to be sensitive to inferred posturally-induced changes in labyrinthine fluid pressure of around 150 mm saline. There was no statistically significant correlation between posturally-induced changes measured by the three techniques. It is suggested that different mechanisms are responsible for the posturally-induced changes observed for the three techniques.

Adult↗
PubMed1990

Lesser metatarsalgia evaluation and treatment.

Anatomic and biomechanical aspects of the complex topic of metatarsalgia are reviewed. Cause is classified as structural, functional, and a combination of both. Evaluation of the lesion symptom complex is presented and light is shed on reasons for complications after metatarsal osteotomy. Ways to avoid complications are also discussed. The oblique osteotomy with rigid fixation performed at the distal surgical neck or the proximal metaphysis is recommended.

Diagnosis, Differential↗
PubMed1989

Verification of a new test of endolymphatic hydrops.

A new objective test of endolymphatic hydrops has been described previously. The test uses auditory brain-stem response (ABR) techniques to estimate the basilar membrane travelling wave velocity (TWV). The underlying hypothesis is that raised pressure in the scala media will lead to an increase in the stiffness of the basilar membrane and that this will give rise to a travelling wave velocity that is greater than normal. It was considered that verification of the technique could be obtained by carrying out the new test before and during a glycerol dehydration procedure. Patients who required this procedure for verification of the diagnosis or as a prognostic indicator for sacculotomy, underwent the following tests. Prior to dehydration an audiogram, the ABR TWV test and a blood sample (for plasma osmolality) were taken. The patient was then given the appropriate amount of glycerol mixed with lemon juice and laid on a bed in a test room. The audiogram and a blood sample were repeated every hour and the ABR TWV test was repeatedly carried out every twenty minutes between the other tests. Six of these procedures have been carried out. In five of them the 0.5 and 1 kHz average threshold improved by at least 10dB and in all those cases the ABR TWV test showed an abnormal pre-dehydration result which moved towards the normal value following dehydration. One patient gave ABR TWV results that were within normal limits before and during the procedure and gave an audiometric change of only 5dB.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Keratoconus: diagnosis and management.

Keratoconus is a common condition whose clinical features represent a common effect on the cornea of a number of diverse processes. This review deals with the clinical signs and accompanying histological and biochemical changes within the cornea, evaluates the significance of associated ocular and systemic conditions and assesses the incidence and prevalence of the disorder. The wider ophthalmic community shares in the treatment of keratoconus, so the general principles of contact lens fitting associated with this difficult condition are examined and the specific protocol used at the Flinders Medical Centre is presented. When contact lenses are not tolerated or an adequate improvement in visual acuity is not achieved, surgery is the next option, so a full assessment is made of the risks and benefits of penetrating keratoplasty. Older techniques, such as thermokeratoplasty and lamellar keratoplasty, are examined and the new technique of epikeratophakia is evaluated.

Conjunctivitis↗
PubMed1989

Effects of posture and age on tympanic membrane displacement measurements.

This study used changes in posture to investigate the transmission of cerebro-spinal fluid (CSF) pressure changes to the cochlear fluids in subjects falling into two age groups. Results were obtained from 32 subjects: 16 aged 19 to 32 years and 16 aged between 40 and 63. Measurements were made with the subject sitting upright and then at 63 degrees to the vertical, using a technique which measures displacement of the tympanic membrane in response to acoustic stimulation of the stapedial reflex. Changes in such measurements are believed to represent changes in perilymphatic fluid pressure. Statistical analysis of the results showed the magnitude of changes in Tympanic Membrane Displacement (TMD) measurements with postural change to be smaller in the older group than in the younger age group. In addition, a larger proportion of the older subjects showed no change in TMD measurements with change in posture. The proportion of subjects in each age group who showed no change in TMD measurements with change in posture was similar to the proportion of temporal bones of subjects of similar ages that had non-patent cochlear aqueducts as determined by a previous histopathological study. Audiometric testing revealed a link between hearing threshold and presumed patency of the communication routes between cochlear and cranial fluids. The magnitude of the tympanic membrane displacement was found to decrease with age in agreement with previous studies showing decrease of stapedial reflex magnitude with increasing age. It is suggested that the communication between cochlear and cranial fluids may be important in the pathogenesis of auditory dysfunction in several patient groups.

Adult↗
PubMed1988

Anaesthetic induction with isoflurane or halothane. Oxygen saturation during induction with isoflurane or halothane in unpremedicated children.

The authors performed a randomised, prospective trial in which one junior anaesthetist administered gaseous induction of anaesthesia to 50 unpremedicated children with either isoflurane or halothane in nitrous oxide and oxygen. Arterial oxygen saturation and the electrocardiogram were monitored and the incidence of complications noted. Desaturation below 85% occurred in six children, but only with isoflurane. The incidences of complications and desaturation events did not alter throughout the 25 isoflurane inductions. Coughing, movement, laryngospasm and sinus tachycardia occurred more frequently with isoflurane. Isoflurane inductions took longer (7.9 as compared with 5.4 minutes, p less than 0.001) and had 4.25 times the number of complications.

Anesthesia, Inhalation↗