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Biomedical subjects

K Payne

Publications and source records attributed to K Payne.

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

Augmentation of human T cell leukaemia virus type I Tax transactivation by octamer binding sites.

The human T cell leukaemia virus type I (HTLV-1) Tax protein is an activator of viral and cellular gene expression. Tax does not bind DNA directly, but does interact with cellular DNA binding proteins. These interactions bring Tax to a specific group of promoters and may help to determine the specificity of Tax transactivation. Previous studies have demonstrated that the activity of Tax, when tethered to a given promoter, is enhanced by the presence of adjacent transcription factor binding sites. To examine the specificity of this augmentation, a series of transcription factor binding sites was tested for the ability to enhance the activity of a Gal-Tax fusion protein. The greatest increase in Gal-Tax activity was observed when an octamer binding site was placed adjacent to the Gal4 binding sites. However, the octamer binding site failed to independently function as a Tax responsive element in the absence of an adjacent Tax-tethering element. Oct-2 was not required for augmentation of Gal-Tax activity as this enhancement was observed in BHK-21 cells, which lack Oct-2. The ability of octamer binding sites to augment transcription was specific for Gal-Tax, as compared to other transactivators. Taken together, these results demonstrate that the degree of Tax transactivation can be influenced by the elemental composition of the target promoter.

Animals↗
PubMed1997

The influence of surface atmospheric conditions on the range and area reached by animal vocalizations.

Low-level vertical changes in temperature and wind exert powerful and predictable influences on the area ensonified by animal vocalizations. Computer modelling of low-frequency sound propagation in measured atmospheric conditions predicts that the calls of the savanna elephant at these frequencies can have ranges exceeding 10 km and that the calls will be highly directional in the presence of wind shear. Calling area is maximized under temperature inversions with low wind speeds. Calling area changes substantially over 24 h periods; on any given day, the calling area undergoes an expansion and contraction which may be as large as one order of magnitude. This cycle is modulated by topography, regional weather patterns, seasonality and possibly by climate variation. Similar influences affect the somewhat higher-frequency calls of lions and may be a selective pressure towards their crepuscular and nocturnal calling behaviour. Coyotes and wolves, which also live in areas with strong and prevalent nocturnal temperature inversions, show similar calling patterns, maximizing their chances of being heard over the longest possible distances. The pronounced dawn and evening vocalization peaks in other animals including birds, frogs and insects may reflect the same influences in combination with other factors which selectively limit high-frequency sound propagation. Atmospheric conditions therefore need to be taken into account in many field studies of animal behaviour. A simplified method for estimating sound propagation during field studies is presented.

Animals↗
PubMed1996

Physicians' attitudes about the care of patients in the persistent vegetative state: a national survey.

OBJECTIVE: To study the attitudes and beliefs of physicians who have experience caring for patients in the persistent vegetative state (PVS). DESIGN: Mailed questionnaire survey. PARTICIPANTS: 500 physicians, 250 from the American Academy of Neurology and 250 from the American Medical Directors Association. MEASUREMENTS: Physicians' beliefs about diagnosis of the PVS, patient awareness and suffering, treatment withdrawal, appropriate use of health maintenance and life-prolonging therapies, organ donation, lethal injection, and the treatment they would want if they were in the PVS. RESULTS: 68% of surveyed neurologists and 60% of medical directors responded. Thirteen percent of responders believe that patients in the PVS have awareness and experience hunger and thirst; 30% believe they experience pain. Fewer than 9% believe that respiratory failure, cardiogenic shock, acute renal failure, or cancer should be aggressively treated. Eighty-nine percent believe that it is ethical to withdraw artificial hydration and nutrition. Almost two thirds of responders believe that it would be ethical to use the vital organs of patients in the PVS for transplantation, and 20% believe that it would be ethical to hasten the patient's death by lethal injection. CONCLUSIONS: When evaluating the appropriateness of treatments for patients in the PVS, neurologists and medical directors largely concur. Most physicians in both groups believe that patients in the PVS would be better off dead; that it is not necessary to provide aggressive therapeutic interventions; and that all therapeutic interventions, including artificial nutrition and hydration, can be withheld in certain circumstances. The areas of consensus are remarkable and suggest that an ethical standard that physicians believe should be followed when caring for these patients may be emerging.

Acute Disease↗
PubMed1996

Comparing dihydroergotamine mesylate and sumatriptan in the management of acute migraine. A retrospective cost-efficacy analysis.

The annual cost of managing migraine totals billions of US dollars. This retrospective economic analysis of a clinical trial comparing subcutaneous dihydroergotamine mesylate (DHE) with subcutaneous sumatriptan in the treatment of acute migraine is appropriate because, although each product has been shown to be efficacious, the acquisition cost of sumatriptan is over 3 times that of DHE. Total costs in each treatment group were calculated and applied independently to 11 clinical trial efficacy measures. Three of the efficacy measures showed no statistically significant difference between treatment arms, leading to a decision to use the less expensive DHE. In 4 of the efficacy measures. DHE was the obvious choice because it is more efficacious and less expensive. For the final 4 efficacy measures, where sumatriptan is more efficacious and more expensive, incremental cost-efficacy ratios were calculated to determine the additional expenditure required to achieve outcomes associated with quick relief. Depending on the efficacy variable chosen and the assumptions used in the model, the incremental cost-efficacy ratios ranged from $US4000 to $US6700 per year (1993 dollars) for each additional patient who is successfully treated with sumatriptan compared with DHE. Therefore, in a population of 100 migraineurs, an additional 13 to 22 patients would achieve these short term benefits of sumatriptan, although it would cost an additional $US88 395 annually, given the assumptions made. Because each product has unique advantages, we conclude that the more cost-efficacious product is dependent on the outcome of interest and the amount that the patient or provider is willing to pay to achieve that outcome.

Adolescent↗
PubMed1994

The impact of a grief workshop for pediatric oncology nurses on their grief and perceived stress.

Coping with the death of a pediatric patient with whom the nurses has developed a close relationship is reported by nurses as the most stressful experience of being a pediatric nurse. Such losses are inevitable for a pediatric nurse regardless of subspecialty and can contribute to a nurse leaving the specialty or the discipline. To prevent those consequences, nurses' grief needs to be acknowledged, and their grieving needs to be facilitated. The purpose of this study was to determine the impact of a grief workshop on grief symptoms and perceived stress in two groups of pediatric oncology nurses who differed in years of experience in the specialty. Study findings indicated that the workshop affected the two groups differently, with the more experienced nurses reporting significantly higher stress levels after the workshop than did the less experienced nurses. Study findings are interpreted and recommendations for future work are offered.

Adaptation, Psychological↗
PubMed1991

Exhibitionists: sexual preferences for exposing.

An assessment of the sexual preferences of exhibitionists and matched non-offenders, revealed greater arousal to scenes of exposing among the offenders but the actual degree of deviant preferences was not marked. Closer analyses of the individual response profiles, using various criteria for deviance, indicated that only a small proportion of exhibitionists displayed deviant arousal. We take these results, along with the findings from previous research, to deny the primacy of sexual motivation in exhibiting behavior. We also consider these results to indicate that there is little value in determining the sexual preferences of exhibitionists when planning treatment or estimating their risk to re-offend.

Adult↗
PubMed1990

Noninvasive evaluation of the upper extremity.

Vascular problems of the arm and hand can be assessed by a number of noninvasive modalities that are chosen on the basis of the history and physical examination. For suspected upper-extremity ischemia, we begin with SLPs and velocity-waveform analysis. The former test will define the extent and approximate location of the disease process, and subjective assessment of the waveform will further determine the degree and location of occlusive disease. When digital ischemia is suspected, the Doppler examination combined with intermittent compression of the radial and ulnar arteries is valuable for defining the variable arterial anatomy of the hand and the patency of the common and proper digital arteries. The extent of distal ischemia can be assessed by digital pressures. Duplex scanning has been found to be of value in determining the source of upper-extremity micro-emboli, in imaging suspected aneurysmal changes, and for evaluating arteriovenous fistulae and bypass grafts. Cold testing is used to confirm the diagnosis of Raynaud's disease after excluding proximal occlusive disease. When symptoms suggest intermittent arterial obstruction, arterial compression at the thoracic outlet is assessed by monitoring the arterial waveform during a series of maneuvers that change the anatomy of the outlet. Although a combination of IPG and venous Doppler examination accurately identifies venous occlusion, we routinely use duplex scanning in this setting. In addition to providing both anatomic and hemodynamic information about the subclavian vein, the jugular vein and the junction of the innominate vein can also be studied. Because of its ability to image in a coronal plane, MRI scanning is another nonivasive study that we have found useful for evaluation of venous anatomy and patency of the subclavian, jugular, and innominate veins. Venous thrombosis, often the first manifestation of subclavian vein compression at the thoracic inlet, is best evaluated using duplex scanning.

Arm↗
PubMed1990

Mesenteric flow velocity variations as a function of angle of insonation.

This study was designed to quantitate variations in duplex ultrasound arterial flow velocities (cm/sec) in the common carotid artery and the superior mesenteric artery that were produced by changes in the angle of pulsed Doppler insonation. Duplex scanning was used to measure peak systolic flow velocity and mean velocity at angles from 30 degrees to 80 degrees; individual measurements were made at 10-degree increments in both the common carotid artery and the superior mesenteric artery in normal subjects. Peak systolic velocity in the common carotid artery varied from 86 cm/sec at 30 degrees to 168 m/sec at 80 degrees. Over the same transducer angle variation mean velocity ranged from 28 to 53 cm/sec. Similar changes in the superior mesenteric artery flow velocities were observed by varying the angle of insonation, where peak systolic velocity varied from 108 cm/sec (30 degrees) to 280 cm/sec (80 degrees), and mean velocity ranged from 29 cm/sec (30 degrees) to 71 cm/sec (80 degrees). Measurements taken from 70 to 80 degrees produced the most dramatic deviation from those taken at 60 degrees. In the common carotid artery the 70- and 80-degree angles produced 14% and 59% increases, respectively, in peak systolic velocity and 16% and 63% increases, respectively, in mean velocity. In the superior mesenteric artery 70-degree and 80-degree angles produced 16% and 120% increases, respectively, in peak systolic velocity and 17% and 111% increases, respectively, in mean velocity. At 80 degrees the percent increases in measured flow velocities for the superior mesenteric artery were significantly greater than those for the common carotid artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1989

The pharmacokinetics of midazolam in paediatric patients.

A serum concentration profile study on midazolam in children was done. Fifty six children aged 3-10 years took part. The routes investigated were intravenous, intramuscular, rectal and oral at 0.15 mg.kg-1, and the oral at 0.45 mg.kg-1 and 1 mg.kg-1. Serum concentration levels for 5 h were studied using gas liquid chromatography. The volume of distribution, Vss, was 1.29 l.kg-1, the elimination half-life 1.17 h and the serum clearance 9.11 ml.kg-1.min-1. Peak serum concentrations for the intramuscular, rectal and oral routes were at 15 min, 30 min and 53 min respectively. Bioavailability was 87%, 18%, 27% respectively at a dose of 0.15 mg.kg-1. The oral route bioavailability halved to 15% at the two higher doses. Bioequivalence was present between the 0.15 mg.kg-1 intramuscular dose and the 0.45 mg.kg-1 oral dose from 45 to 120 min.

Administration, Oral↗
PubMed1987

Caudal block for analgesia after paediatric inguinal surgery.

Two hundred and eleven children aged 1-5 years were studied after undergoing herniorrhaphy or orchiopexy. In 111 cases a caudal block was used for postoperative analgesia. This was administered immediately after induction of anaesthesia, using bupivacaine 0.25% plain (0.7 ml/kg lean body mass), and was successful in 100 patients. A mean analgesic level (+/- SE) of T9.9 +/- 0.47 was achieved (range L2-T6). In 5 cases no block occurred and in 6 the level was below T12. The other 100 children acted as controls. Behaviour patterns were more restful in the caudal block group on awakening and less opiate was required during the first 5 postoperative hours. No complications resulted.

Anesthesia, Caudal↗
PubMed1984

Plasma glucose levels in the peri-operative period in children.

Peri-operative plasma glucose levels were studied in one hundred children under 5 years of age and under 20 kg. All underwent procedures of less than 30 minutes. Of 32 cases under the third percentile for weight, ten developed low plasma glucose during the pre-operative and/or postoperative phase. This occurred despite receiving 5% dextrose by mouth 4 hours before induction. Even in children of normal weight there was a low incidence of peri-operative hypoglycaemia. Routine intravenous glucose-containing fluids are thus recommended during the peri-operative period.

Anesthesia↗
PubMed1977

Social organization and mating success in local song populations of village indigobirds, Vidua chalybeata.

Behavioral interactions among color-marked individual Vidua chalybeata that shared common song dialects were observed for 5 years in two populations at Lochinvar National Park, Zambia. Social interactions involved males visiting and competing for mating sites and female visiting male in an apparent sampling of potential copulating partners. Differences in mating success among the polygynous males were compared with male behavior and territory resources, and criteria were developed to test the importance of intrasexual male competition and female mate choice in explaining the mating system of the populations. Song behavior best explained differences in mating success of males, with lesser effects of neighboring males and the defensible resources around the call-sites. The social organization of song populations resembles that of a dispersed lek with females visiting many males but mating with few males. We discuss the observations on indigobirds in relation to behavioral selection, sexual selection, and mating systems. Mating systems of certain populations and species are compared using statistics of individual mating success.

Aggression↗
PubMedDate not supplied

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Aged↗