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Biomedical subjects

R Sutton

Publications and source records attributed to R Sutton.

At least 217 records · Page 12Linked to original sources
PubMed1982

Immunoglobulin E antibodies to ingested cereal flour components: studies with sera from subjects with asthma and eczema.

The specificity of immunoglobulin E for different cereal grain proteins was investigated using sera from twenty paediatric patients with asthma and/or eczema. Close correlations were observed between radioallergosorbent test values for grain extracts of wheat, rye and barley, and, to a lesser extent, oats. Of the different wheat four fractions tested, the globulins and glutenins consistently bound higher levels of IgE than the gliadins and albumins. This is in contrast both with bakers' asthma (an allergy to inhaled flour where the albumins are important allergens) and with coeliac disease (in which gliadin is the most toxic fraction). Partial digestion of the flour proteins largely removed their ability to bind IgE. An analytical technique of identifying allergens after gel isoelectric focusing demonstrated that many different flour proteins were involved.

Adolescent↗
PubMed1982

The import of carbamoyl-phosphate synthase into mitochondria from foetal rat liver.

A putative precursor of carbamoyl-phosphate synthase was isolated from a microsomal wash fraction and purified by high-pressure liquid chromatography. Autolytic degradation and limited proteolysis were used to characterize the putative precursor of carbamoyl-phosphate synthase and to show its similarity to the processed enzyme. The carbamoyl-phosphate synthase precursor underwent a time-dependent and concentration-dependent conversion into a dimeric or polymeric form. When labelled with 125I and incubated with foetal rat liver mitochondria the precursor was bound to the mitochondria and about 30% of the label was imported into the matrix space. This labelling required the presence of ATP and was time-dependent. Mitoplasts also imported the carbamoyl-phosphate synthase precursor. After import of the precursor, increases in carbamoyl-phosphate synthase activity could be demonstrated in foetal rat liver mitochondria.

Adenosine Triphosphate↗
PubMed1982

Carotid sinus syncope treated by pacing. Analysis of persistent symptoms and role of atrioventricular sequential pacing.

Seventy patients have been paced for carotid sinus syndrome over four years. Twelve patients had persistent symptoms despite adequate ventricular pacing. Patients with persistent symptoms were found to have a significant vasodepressor response, a significant hypotensive response to ventricular pacing (pacemaker effect), and a severe hypotensive response to carotid sinus massage with introduction of ventricular pacing, which reproduced symptoms in all patients. A group of 14 asymptomatic paced carotid sinus patients was found to have a significantly lower vasodepressor response, pacemaker effect, and combined vasodepressor response plus pacemaker effect than the group with persistent symptoms. Atrioventricular sequential pacing was shown to eliminate the hypotensive effect of ventricular pacing and is considered to be the treatment of choice for patients with carotid sinus syndrome who have both cardioinhibitory and significant vasodepressor responses.

Aged↗
PubMed1981

Modern atrial and ventricular leads for permanent cardiac pacing.

Three hundred and fifteen transvenous pacing leads of various modern designs have been assessed over a period of three years. Of these, 103 were implanted in the atrium and 212 in the ventricle. Screw-in leads in the right atrial appendage and short tined leads in the ventricle have resulted in the virtual elimination of lead displacement, and a very low incidence of other lead related problems. In two lead systems it has been found advantageous to have both leads constructed of urethane.

Electrodes, Implanted↗
PubMed1980

The transport and accumulation of adenine nucleotides during mitochondrial biogenesis.

The atractyloside-insensitive accumulation of adenine nucleotides by rat liver mitochondria (as opposed to the exchange-diffusion catalysed by the adenine nucleotide translocase) has been measured by using the luciferin/luciferase assay as well as by measuring [14C]ATP uptake. In foetal rat liver mitochondria ATP is accumulated more rapidly than ADP, whereas AMP is not taken up. The uptake of ATP occurs against a concentration gradient, and the rate of ATP uptake is greater in foetal than in adult rat liver mitochondria. The accumulated [14C]ATP is shown to be present within the mitochondrial matrix space and is freely available to the adenine nucleotide translocase for exchange with ATP present in the external medium. The uptake is specific for ATP and ADP and is not inhibited by adenosine 5'-[beta gamma-imido] triphosphate, GTP, CTP, cyclic AMP or Pi, whereas dATP and AMP do inhibit ATP accumulation. The ATP accumulation is also inhibited by carbonyl cyanide m-chlorophenylhydrazone, KCN and mersalyl but is insensitive to atractyloside. The ATP uptake is concentration-dependent and exhibits Michaelis-Menten kinetics. The divalent cations Mg2+ and Ca2+ greatly enhance ATP accumulation, and the presence of hexokinase inhibits the uptake of ATP by foetal rat liver mitochondria. These latter effects provide an explanation for the low adenine nucleotide content of foetal rat liver mitochondria and the rapid increase that occurs in the mitochondrial adenine nucleotide concentration in vivo immediately after birth.

Adenine Nucleotides↗
PubMed1980

Inhibition of adenosine triphosphatase, 5-hydroxytryptamine transport and proton-translocation activities of resealed chromaffin-granule 'ghosts'.

1. Highly purified resealed chromaffin-granule ;ghosts' were assayed for ATPase and ATP-driven H(+)-translocation and 5-hydroxytryptamine-uptake activities, and for 5-hydroxytryptamine uptake driven by an imposed transmembrane H(+)-gradient. The effects of several inhibitors on these activities were studied. 2. Dicyclohexylcarbodi-imide inhibits all of these activities, but not in parallel; at low concentrations it decreases the permeability of the membrane to protons. 3. 4-Chloro-7-nitrobenzofuran (Nbf-Cl) and silicotungstate inhibit ATP-dependent activities, without effect on 5-hydroxytryptamine uptake driven by an imposed H(+)-gradient. 4. Tributyltin chloride inhibits all of the activities. 5. Treatment of the ;ghosts' with low concentrations of urea inhibits 5-hydroxytryptamine uptake and ATP-dependent generation of a transmembrane H(+)-gradient, without inhibiting ATPase activity. 6. Nbf-Cl and silicotungstate are without effect on the rate of leakage of 5-hydroxytryptamine from preloaded ;ghosts', whereas dicyclohexylcarbodi-imide and tributyltin chloride accelerate the rate of leakage. 7. Treatment of the membranes with (14)C-labelled Nbf-Cl labels several proteins; membranes treated with dicyclohexyl[(14)C]carbodi-imide are labelled predominantly in a protein of low molecular weight, which may be analogous to the mitochondrial H(+)-conducting proteolipid. 8. It is concluded that Nbf-Cl and silicotungstate inhibit the H(+)-translocating ATPase of the granule membrane; that dicyclohexylcarbodi-imide inhibits the ATPase, and inhibits 5-hydroxytryptamine accumulation by accelerating leakage of the amine; and that the effects of tributyltin chloride are due to inhibition of the ATPase, and collapse of the transmembrane H(+)-gradient through OH(-)-anion exchange.

Adenosine Triphosphatases↗
PubMed1980

Hormone-initiated maturation of rat liver mitochondria after birth.

1. The injection of adrenaline, glucagon or cyclic AMP into foetal rats in utero initiates the maturation of energy transduction in rat liver mitochondria before birth. 2. The injection of the beta-blocker, propranolol, prevents this maturation process. 3. The maturation of mitochondrial energy transduction is measured in terms of the increase in the respiratory control index and mitochondrial adenine nucleotide concentration. 4. It is postulated that the actions of the hormones, acting through cyclic AMP, affect glycogenolysis and glycolysis to give rise to transient localized high concentrations of ATP. 5. It is the ATP that acts as the molecular trigger, effecting mitochondrial maturation.

Adenine Nucleotides↗
PubMed1980

Physiological cardiac pacing.

With the availability of reliable transvenous atrial leads and advances in electronic and battery technology, pacing for the restoration of the atrioventricular sequence has become practicable. This paper presents (1) a historical review of physiological cardiac pacing, and (2) a functional description of pacemakers currently available or in clinical validation. The indications and limitations of use for each is discussed on the basis of clinical experience in 176 patients. Predictions are made for future application of sophisticated pacemaker systems after the remaining clinical and technological barriers are overcome.

Cardiac Pacing, Artificial↗
PubMed1980

Unsuspected coronary artery disease as cause of chronic atrioventricular block in middle age.

Attention has recently been drawn to the relatively poor prognosis of middle aged patients paced for chronic atrioventricular block when age-linked expectation of life is taken into account, and it has been suggested that this may be the result of underlying coronary artery disease, despite the absence of symptoms to suggest this. It was the purpose of this study to determine the incidence of unsuspected coronary artery disease in middle aged patients presenting with chronic atrioventricular block. Studies were made on a consecutive series of 30 patients aged 45 to 65 (mean age 56 years) with chronic atrioventricular disease who had been referred for pacing. Patients presenting with acute myocardial infarction or angina or with sinuatrial disease without atrioventricular disease were excluded. Coronary arteriography disclosed the presence of severe coronary artery disease in 13 patients. Of the remaining 17 patients, four had congestive cardiomyopathy, two had hypertrophic cardiomyopathy, one had aortic stenosis, and in 10 patients the aetiology of the heart block was unknown. Myocardial revascularisation was undertaken in six patients with paroxysmal atrioventricular block caused by coronary artery disease. Operation did not result in any sustained improvement in atrioventricular conduction.

Aged↗
PubMed1979

Electrophysiological and haemodynamic basis for application of new pacemaker technology in sick sinus syndrome and atrioventricular block.

A fundamental description of pacemaker systems which are commercially available or in clinical validation is given as a background for their application in a series of 62 consecutive patients presenting over a period of 1 year for permanent cardiac pacing. The patients (23 (37%) sick sinus syndrome, 38 (61%) atrioventricular block, and 1 ventricular tachycardia) were studied electrophysiologically and haemodynamically to allow the appropriate application of a pacemaker system. In sick sinus syndrome, 8 patients had permanent atrial pacing, 14 ventricular pacing, and 1 atrioventricular sequential pacing; in atrioventricular block, 8 patients had atrial synchronous ventricular inhibited pacing and the remaining 30 had ventricular pacing. A high incidence of atrial fibrillation, 9 patients, and abnormal sinus node function, 15 patients, precluded wider use of atrial synchrony. The results show benefit in acute haemodynamic studies of using systems including atrial sensing and/or pacing, and with greater availability of atrioventricular sequential and still more advanced pacemakers with dual sensing as well as dual pacing the majority of patients may be offered this benefit.

Aged↗