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Biomedical subjects

P Reilly

Publications and source records attributed to P Reilly.

At least 19 recordsLinked to original sources

Malignant astrocytoma in South Australia: treatment and case survival.

Kernohan grade III and IV astrocytomas are usually fetal and in the past have had a case survival rate of only about 10% two years from diagnosis. Data on 285 cases registered at the Royal Adelaide Hospital in 1977-1986 showed a median survival of approximately six months. The survival rate was 25% at one year and 15% at two years. Survival reduced markedly with increase in age at diagnosis from a two-year rate of 53% for patients under 40 years of age to 5% for patients aged 70 years or more. This may have been due in part to the more frequent treatment of younger patients by decompression and radiotherapy. Apart from age and treatment mode, factors related to extended survival included a longer duration of symptoms before diagnosis and location of the tumour in the frontal lobes. Notwithstanding prospects for an increase in short-term survival from the use of radiotherapy as an adjunct to surgery, long-term outcomes for these neoplasms are still very poor.

Adult

Intercellular adhesion molecule-1 (ICAM-1) in the pathogenesis of asthma.

Airway eosinophilia, epithelial desquamation, and hyperresponsiveness are characteristics of the airway inflammation underlying bronchial asthma. The contribution of intercellular adhesion molecule-1 (ICAM-1) to eosinophil migration and airway responsiveness was studied. ICAM-1 partially mediated eosinophil adhesion to to endothelium in vitro and was upregulated on inflamed bronchial endothelium in vivo. ICAM-1 expression was also upregulated on inflamed airway epithelium in vitro and in vivo. In a primate model of asthma, a monoclonal antibody to ICAM-1 attenuated airway eosinophilia and hyperresponsiveness. Thus, antagonism of ICAM-1 may provide a therapeutic approach to reducing airway inflammation, hyperresponsiveness, and asthma symptoms.

Animals

Adsorptive stripping voltammetry of F(ab')2 and Fab fragments of anti-mouse immunoglobulin G.

The adsorptive stripping voltammetric behaviour of F(ab')2 and Fab fragments of anti-mouse immunoglobulin G is described. Conditions were optimized for the determination of these fragments with respect to accumulation potential, accumulation time, scan rate, pulse amplitude, drop size and electrolyte composition. The F(ab')2 and Fab fragments gave rise to behaviour similar to that reported previously for the intact immunoglobulin.

Adsorption

Molecular cloning and sequencing of the psaD gene encoding subunit II of photosystem I from the cyanobacterium, Synechocystis sp. PCC 6803.

Photosystem I reaction center was isolated from the cyanobacterium, Synechocystis sp. PCC 6803, in a form which contains seven different polypeptide subunits. One of the subunits, with a molecular mass of about 16 kDa, was isolated, and protein sequence information was obtained for the amino terminus and several tryptic peptides. Oligonucleotide probes, corresponding to these sequences, were used to probe a genomic library, and the gene, designated psaD, encoding subunit II was cloned and sequenced. The gene encodes a polypeptide with a mass 15,644 Da, which exhibits a high degree of similarity to subunit II from tomato, as well as amino acid sequences reported from barley photosystem I. In addition to this gene, three large open reading frames were identified. Two remain unidentified, and the third is highly homologous to anthranilate synthase, component 1 from Escherichia coli and Saccharomyces cerevisiae.

Amino Acid Sequence

Blood conservation with membrane oxygenators and dipyridamole.

Cardiopulmonary bypass induces platelet activation and dysfunction, which result in platelet deposition and depletion. Reduced platelet numbers and abnormal platelet function may contribute to postoperative bleeding. A membrane oxygenator may preserve platelets and reduce bleeding more than a bubble oxygenator, and the antiplatelet agent dipyridamole may protect platelets intraoperatively and reduce bleeding postoperatively. A prospective randomized trial was performed in 44 patients undergoing elective coronary artery bypass grafting to assess the effects of the membrane oxygenator and dipyridamole on platelet counts, platelet activation products, and postoperative bleeding. Patients who were randomized to receive a bubble oxygenator and no dipyridamole had the lowest postoperative platelet counts, the greatest blood loss, and the most blood products transfused. Platelet counts were highest and blood loss was least in patients randomized to receive a membrane oxygenator and dipyridamole (p less than .05). A bubble oxygenator with dipyridamole and a membrane oxygenator without dipyridamole resulted in intermediate postoperative platelet counts and blood loss. Arterial thromboxane B2 and platelet factor 4 concentrations were elevated on cardiopulmonary bypass in all groups. Both the membrane oxygenator and dipyridamole were independently effective (by multivariate analysis) in preserving platelets. Optimal blood conservation was achieved with a membrane oxygenator and dipyridamole.

6-Ketoprostaglandin F1 alpha

Tissue perfusion rate determined from the decay of oxygen-15 activity after photon activation in situ.

Rates of cerebral perfusion were obtained from measurements of the disappearance (wash-out) of oxygen-15 after in situ tissue activation with 45-million-volt x-rays. In an anesthetized cat, typical values were 90 milliliters per minute per 100 grams of tissue, with 55 percent wash-out. In a specific radiotherapy patient, the value was 65 milliliters per minute per 100 grams of tissue, with 63 percent wash-out of oxygen-15 through incorporation into tissue water.

Animals

Differential radiolabelling of lymphocyte membrane alloantigens and immunoglobulins: variation of H2O2 concentration during lactoperoxidase catalyzed cell surface radio-iodination.

The effect of H2O2 concentration on lactoperoxidase catalyzed cell surface radio-iodination and subsequent isolation of Murine splenic lymphocyte Ia, H-2K and Lyb-3 surface antigens and membrane immunoglobulins was studied. For most membrane polypeptides analyzed 0.3 mM H2O2 proved to be optimal for the recovery of radiolabelled antigens from detergent lysates of labelled cells by immunoprecipitation. Marked variations among surface antigens and membrane immunoglobulin polypeptide chains were observed for the iodination and recovery of these proteins above and below the optimal peroxide concentration. The results suggest that cell surface radio-iodination conditions should be standardized to the requirements of the particular membrane protein being studied. The differential iodination and recovery of discrete membrane components above and below optimal conditions may prove useful in the analysis of surface membrane protein structure and membrane association.

Animals

Exercise training and plasma catecholamines in patients with ischemic heart disease.

A 3 month program of exercise training was carried out in 10 patients with ischemic heart disease to assess the contribution of catecholamines to the training effect of improved exercise capacity and enhanced myocardial oxygen delivery. Training resulted in a significant increase in maximal treadmill exercise time (mean +/- standard error the mean 374 +/- 28 versus 567 +/- 33 seconds, P less than 0.0001). The heart rate-arterial pressure product, an index of myocardial oxygen consumption, was decreased at rest and at all levels of exercise after training. After training, the mean plasma norepinephrine level during supine rest was reduced (320 +/- 23 to 191 +/- 20 pg/ml, P less than 0.01) and plasma epinephrine values were unchanged. When these previously sedentary patients exercised on a treadmill to the maximal level attained before exercise training, the mean plasma norepinephrne and plasma epinephrine concentrations were significantly reduced. These data suggest that the beneficial adaptations of the cardiovascular system to exercise training are at least partially mediated by changes in the catecholamine response to exercise.

Adult

Effects of alpha-MSH on motivation, vigilance and brain respiration.

In a series of experiments designed to assess the effects of alpha-MSH on various motivational processes, it was observed that the hormone can slightly decrease food intake and increase water consumption during the first hr after administration in rats. alpha-MSH also modified avoidance behavior in 1- and 3-day-old chicks, but there were no reliable effects on activity, distress vocalizations and the tonic immobility response. alpha-MSH appeared to modulate the sleep-waking activity of rats, and the most prominent effect was an increase of slow wave sleep during the 2-3 rd hr after treatment. A possible second effect was a homogenization of sleep patterns--with poor sleepers exhibiting increases of activated sleep and good sleepers a reduction. Measurement of in vitro brain oxygen consumption indicated that mice treated with alpha-MSH exhibit an 18% reduction in respiration of the brain stem section which includes the locus coeruleus, but did not reliably change respiration in forebrain cortices. alpha-MSH also produced a modest 14% increase of plasma glucose. These results are discussed in terms of possible modulation by alpha-MSH of activity in central autonomic cell groups such as the locus coeruleus.

Animals