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Biomedical subjects

A Cairns

Publications and source records attributed to A Cairns.

At least 19 recordsLinked to original sources
PubMed1997

Primary tumours of the vestibule and inner ear.

Seven primary tumours of the vestibule and inner ear are described, six schwannomas and one traumatic fibroma. Schwannomas in this situation may occur as sporadic tumours, or may be a feature of neurofibromatosis type 2 (NF-2). In the latter condition they may occur in isolation or in association with, but separate from, schwannomas arising in the internal meatus. Direct extension into the vestibule of an intrameatal vestibular schwannoma is well reported, but extension of an intravestibular tumour into the internal meatus is not described. Traumatic fibromas of the vestibule are rare and the trigger could be an attack of labyrinthitis. Intravestibular tumours, although rare, are likely to be diagnosed with increasing frequency with the widespread use of MR imaging.

Adult↗
PubMed1996

Giant cell hepatitis associated with systemic lupus erythematosus.

Giant hepatocytes are commonly found in several neonatal and infantile liver diseases, but are rarely found in adult liver disease. A 42 year old white woman presented with a five month history of paraesthesia and numbness of both the upper and lower limbs and with vague abdominal pain. Abnormal liver function was noted on routine screening. Ultrasound scan of the abdomen showed gallstones; barium enema, ERCP and computed tomography scan were all normal. IgG antibodies to double stranded DNA were present at a titre of 40 units. Anti-cardiolipin antibodies, anti-mitochondrial antibodies and rheumatoid factor were not detected. Serology for hepatitis A, B, C, and paramyxoviruses was negative, as was the Paul Bunnell test. A clinical diagnosis of systemic lupus erythematosus (SLE) with an axonal sensory polyneuropathy was made, the latter confirmed on biopsy of the sural nerve. Giant cells were noted on liver biopsy. The patient was treated with corticosteroids; liver function had improved after two years of follow up. When extensive giant cell transformation is noted on liver biopsy, particularly when neuropathy is also a feature, the possibility of an association with SLE should be considered.

Adult↗
PubMed1996

Effect of the beta-agonist clenbuterol on dexamethasone-induced diaphragm dysfunction in rabbits.

The present study was designed to examine whether clenbuterol (CLEN) could reduce dexamethasone (DEX)-induced diaphragm dysfunction. We studied four groups of New Zealand white (NZW) rabbits, each receiving one of the following daily injections subcutaneously for 2 wk: saline (control), DEX 3 mg/kg, DEX 3 mg/kg + CLEN 2 mg/kg, and CLEN 2 mg/kg. Diaphragm fiber cross-sectional areas (CSA) were measured. Twitch transdiaphragmatic pressure (Pdi) and tetanic Pdi were measured during bilateral phrenic stimulation both before and after 60 min of inspiratory resistive loading (IRL). DEX produced a marked atrophy of type IIa and type IIb diaphragm fibers. This diaphragm atrophy was prevented by CLEN in the DEX plus CLEN group. CLEN alone increased CSAs of all three types of diaphragm fibers. Significant reductions in twitch Pdi and tetanic Pdi at all stimulation frequencies both before and after IRL were observed similarly in the DEX group as well as in the DEX plus CLEN group compared with the control animals. We conclude that DEX produces significant diaphragm atrophy and decreases diaphragmatic contractility. CLEN produces hypertrophy of the diaphragm and minimizes diaphragm atrophy induced by DEX, but it has no demonstrable protective effect on DEX-induced diaphragm dysfunction.

Adrenergic beta-Agonists↗
PubMed1995

Continued prescribing of inappropriate drugs in general practice.

Seven general practitioners used various methods to identify patients in their practices whom they had inherited and whose medication they regarded as inappropriate in the light of current knowledge. Information was collected in each case about the drug concerned, the patient, the original prescriber, and the reason for continued prescribing. Each patient was also interviewed. Altogether, 25 different drugs were prescribed for 40 patients: in 16 the inappropriate drug was one acting on the brain, in 13 an antihypertensive, in seven it was given for heart disease and in three, for asthma. The influence of the original prescriber, and the patient's dependence on the drug, helped to explain its continued use. Almost half the patients said that they might consider changing their medication. The study underlines the importance of reviewing long-term medication and offers a method of scrutinizing repeat prescribing in general practice. Community pharmacists could help in this process.

Adult↗
PubMed1995

Stability of evoked parasternal intercostal muscle electromyogram at increased end-expiratory lung volume.

The diaphragmatic electromyogram has been measured as an index of the level of diaphragmatic activation. The diaphragmatic electromyogram, however, even when measured by intramuscular electrodes, can be artifactually altered by a change in lung volume (A. Brancatisano, S. M. Kelly, A. Tully, S. H. Loring, and L. A. Engel. J. Appl. Physiol. 66: 1699-1705, 1989) or by a change in body position. The parasternal intercostal muscle may be less subject to the mechanisms that are believed to produce this artifactual change. We asked whether the parasternal intercostal electromyographic activity could be reliable when lung volume changes. Six supine rabbits were anesthetized with ketamine and xylazine. Fine bipolar copper wires, with their tips exposed, were inserted into the left parasternal intercostal muscle in the third interspace. A stimulus that was three times maximal was applied to the corresponding intercostal nerve, and the resulting action potential (AP) was photographed. Parasternal intercostal muscle length was measured by sonomicrometry over the vital capacity range. There were small nonsignificant changes in the AP from functional residual capacity (FRC) to total lung capacity. From FRC to residual volume there was variation in the AP. The AP was also quite stable when regional conductivity was altered but showed variation when the parasternal intercostal muscle length change was accentuated by traction on the rib cage. We conclude that the parasternal intercostal electromyographic activity can be reliably used to measure inspiratory motoneuron output to it over the range of lung volumes from FRC to total lung capacity.

Animals↗
PubMed1995

Phrenic motoneuron firing rates during brief inspiratory resistive loads.

The neural activation of the diaphragm during quiet and vigorously stimulated breathing has been hypothesized to be submaximal. In this study, we measured phrenic motoneuron firing rates during brief progressively increasing inspiratory resistive loads in anesthetized rabbits. We recorded activity in 68 phrenic motoneurons in 17 rabbits. We found that 40 of these axons were active during quiet breathing. Twenty-seven axons were silent during quiet breathing but began to fire as inspiratory loading progressed. The level of drive reflected by transdiaphragmatic pressure where silent phrenic motoneurons were recruited ranged from 5 to 45 cmH2O. Silent motoneurons showed significantly higher average rates of firing and significantly greater increases in firing rate as loading progressed (P < 0.01). The firing rate of both active and silent axons tended to plateau as rates approached 70-80 Hz. All motoneurons except for one, which may have been an afferent, were activated by inspiratory resistive loading. Inspiratory resistive loading activated phrenic motoneurons at high rates, and our results did not support the presence of significant numbers of unrecruited motoneurons.

Animals↗
PubMed1995

Growth screening and urban deprivation.

OBJECTIVES: To assess the effect of urban deprivation on childhood growth in a modern British society by analysing data from a regional growth survey, the Tayside growth study. SETTING: The Tayside Region in Scotland, which has three districts with distinct socioeconomic status: Dundee (D, urban city), Angus (A, rural), and Perth (P, rural and county town). SUBJECTS AND METHODS: Height and weight of 23,046 children (> 90% of the regional childhood population) were measured as part of a child health surveillance programme, by community health care workers at 3, 5, 7, 9, 11, and 14 years. Height standard deviation score (calculated against Tanner) and body mass index (BMI-weight (kg)/height (m)2) were calculated for each child by a central computer program; mean height standard deviation score and BMI standard deviation score were calculated for each measuring centre (school, health clinic). A deprivation score for each centre was calculated from the prevalence of single parent families; families with more than three children; unemployment rate; the number of social class V individuals; the percentage of council houses. RESULTS: Mean height standard deviation score for Tayside was 0.11. An intraregional difference was demonstrated: mean height standard deviation score (SD) D = 0.04 (1.0); A = 0.14 (1.1); P = 0.21 (1.1); P < 0.002. There was a positive association between short stature and increasing social deprivation seen throughout Tayside (P < 0.05), with a strong association in Dundee primary school children (r = 0.6; P < 0.001). Analysis by district showed that the association was significant only above the age of 8 (P < 0.004). There was no relation between BMI and social deprivation. CONCLUSIONS: In an industrialised developed society, urban deprivation appears to influence height mostly in late childhood, and this association should be taken into consideration in the clinical management of short stature. Height seems to be a better physical indicator of urban deprivation, and hence an index of childhood health, than BMI.

Adolescent↗
PubMed1993

Spectral analysis of cervical cells using the discrete Fourier transform.

This paper contains results from a preliminary study of spectral analysis techniques applied to the classification of cervical cells from routinely prepared Papanicolaou cervical smears. Experiments were conducted using a subset of 110 normals and 110 dyskaryotic single cell images randomly selected from a larger cell image data base. An assessment was made of the contribution of different regions within a cell image to the frequency spectrum. Three image sets were used, the original image itself plus two derived from it. In the first derived set, only nuclear size and shape were used. In the second set nuclear morphology and texture were included. Nuclear masking was performed using an interactive segmentation procedure. The discrete Fourier transform was applied to each image in the three image sets and classification experiments were performed using 80 features derived from the frequency spectra. An optimum set of features was selected for each experiment by canonical analysis. Good classification results were obtained when features extracted solely from nuclear shape were used. The inclusion of information relating to nuclear texture improved the results. However, inclusion of the extra nuclear region degraded the classifier's ability to discriminate between cell groups.

Cervix Uteri↗
PubMed1992

Low concentrations of penicillin partially suppress CA3 hippocampal IPSPs in vitro.

Low concentrations of penicillin (50-300 IU/ml) produce a pro-convulsant state in CA3 hippocampus characterized by low amplitude, low frequency (2-3 Hz) spontaneous field potential oscillations. Evoked field potentials were used to demonstrate that this distinct, coordinated behavior of the hippocampal neuronal network which is intermediate between normal activity and fully synchronized epileptiform bursting is the result of partial blockade of GABAA-mediated IPSPs. A new method for estimating the degree of IPSP block relative to convulsant doses of penicillin (2,000 IU/ml) indicates that the half-maximal effect occurs at 300 IU/ml. Fully synchronized bursts may require almost complete IPSP block.

Action Potentials↗
PubMed1992

Evoked CA3 field potentials corresponding to both EPSPs and IPSPs in hippocampal slice.

Biphasic field potentials were recorded in the CA3 distal dendritic region in response to both antidromic (fornix) and orthodromic (mossy fiber) stimulation in guinea pig hippocampal slices in vitro. The positive component (P1) corresponded to intracellularly recorded excitatory postsynaptic potentials. The negative component (N1) appears to be due to GABAA-mediated inhibitory postsynaptic potentials (IPSPs) since it corresponded to the fast IPSP recorded intracellularly, was blocked by bicuculline and penicillin and augmented by barbiturates. The amplitude of N1 and the duration of P1 are sensitive and useful measures of the GABAA-mediated IPSP.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1992

Automation in cervical cytology: an overview.

Cancer of the uterine cervix is one of the more common female cancers and a major source of premature female mortality. UK deaths in 1987 exceeded 2000. To reduce these rates, national screening programmes have been introduced using the Papanicolaou method. In screening for cancer, the examination of specimens is an intensive and expensive task. Its high cost has led to a number of attempts to automate the process, either fully or partially. Over the last 30 years, various experimental prescreening systems have been developed for the diagnosis of cytological samples including the use of image processing techniques. This paper presents a historical overview of automation in cervical cytology and the status of current developments for automated cytological diagnosis.

Automation↗