Search PubMed⌕ Search

Biomedical subjects

A G Fraser

Publications and source records attributed to A G Fraser.

At least 145 records · Page 8Linked to original sources
PubMed1984

Do patients want to be informed? A study of consent for cardiac catheterisation.

One hundred and four patients were asked to recall what they had been told before they gave consent for cardiac catheterisation to be performed. Of these, 14% had received no explanation, 24% had not been warned to expect specific symptoms or side effects, 40% had been told that complications were possible, and 26% had been warned that there was a risk of death. Most patients did not know about these risks, and two thirds would not have wanted to be told about them. Doctors should neither insist on gaining fully informed consent from anxious patients nor deny detailed information to inquiring ones.

Adolescent↗
PubMed1983

A comparison of highly selective vagotomy with truncal vagotomy and pyloroplasty--one surgeon's results after 5 years.

In a prospective randomized trial highly selective vagotomy (HSV) was compared with truncal vagotomy and pyloroplasty (TVP). One surgeon performed all the operations. Ninety-eight per cent of patients were reviewed by two physicians after 20-97 mth (mean 61 mth). Fifty-nine of 68 patients (87 per cent) had an excellent or very good result after HSV (Visick grades I and II) compared with 48 of 69 (70 per cent) after TVP (P less than 0.05). There was 1 proven recurrence after HSV and 4 after TVP. Diarrhoea, including mild symptoms, occurred in 5 patients (7 per cent) after HSV and in 27 (39 per cent) after TVP (P less than 0.001). Severe diarrhoea did not occur after HSV but was present in 4 patients (6 per cent) after TVP (P less than 0.001). Flatulence, epigastric fullness and weight loss were also significantly more common after TVP. On average HSV took 72 min to perform compared with 44 min for TVP (P less than 0.001). Transient dysphagia occurred in 19 patients after HSV compared with 8 after TVP (P less than 0.05). HSV gave better results than TVP and was associated with a low recurrence rate (1.5 per cent at a mean of 5 yr). Although technically more demanding, HSV in our hands is a better operation than TVP for uncomplicated duodenal ulcer.

Adult↗
PubMed1982

The surgical treatment of microtia: a long-term review of 17 patients.

Fourteen children were reviewed approximately 3 1/2 years after surgical reconstruction of the pinna had been completed. Seven had unilateral microtia and seven bilateral microtia, including four caused by thalidomide. Using objective criteria the cosmetic results were disappointing. Treatment entailed protracted hospitalisation, numerous operations and produced adverse emotional and educational sequelae. Nearly all the children covered their ears by growing their hair long. Attempts by the ENT department to improve hearing in the children with bilateral microtia had been disappointing. Three other children who were not treated although they had been referred for surgery were also reviewed. The problems of reconstructive surgery for microtia and the indications for treatment are discussed. It is suggested that reconstruction may be inadvisable for children who have bilateral anotia or associated deformities and who have an unstable family background.

Abnormalities, Multiple↗
PubMed1982

Current approaches to the classification, characterisation and typing of pathogenic anaerobic bacteria.

Characterisation systems based on the demonstration of soluble antigens and toxins are of much practical value but have clear taxonomic limitations. This is illustrated by reference to our work with some of the pathogenic clostridia. The definition and classification of the anaerobic cocci is a difficult and continuing challenge. Systems for the classification and characterisation of the gram-negative non-sporing anaerobic bacilli are evolving well, though there are still some very difficult areas. A selection of the most helpful tests is indicated. Biotyping systems are compared with serotyping systems; the results of serological approaches to characterisation are encouraging. The further exploration of bacteriocin typing seems to be merited. The challenge of characterisation and classification of anaerobic spirochaetes commonly involved in human infections must now be taken up.

Amino Acids↗
PubMed1981

Neuraminidase production by Bacteroidaceae.

The production of neuraminidase (EC 3.2.1.18) by 77 strains of Bacteroidaceae was investigated by techniques previously used to study neuraminidase production by clostridia. Conditions for culture and assay of Bacteroides fragilis neuraminidase were characterised. The enzyme is predominantly cell associated; it is not calcium dependent and the pH optimum for its production is c. 4.5. Most neuraminidase-positive Bacteroides strains produced the enzyme well in the test media but a few strains failed to produce it consistently in one or other of the media. Because of these occasional variations, strains were grown and tested in at least two media before being defined as neuraminidase negative. Within the B. fragilis group of species, B. fragilis, B. vulgatus, B. distasonis, B. ovatus, B. thetaiotaomicron and B. variabilis were neuraminidase positive while B. eggerthii, B. uniformis and B. splanchnicus were negative. Two subspecies of B. melaninogenicus (ss. melaninogenicus and ss. levii) were positive but the other (ss. intermedius) was negative. Strains of B. oralis and B. bivius produced the enzyme while B. ruminicola, B. disiens, B. asaccharolyticus and B. corrodens did not. The microaerophilic B. ochraceus were also positive. None of the Fusobacterium or Leptotrichia species tested produced neuraminidase. Our results for neuraminidase production are consistent for all strains of each species examined and we suggest that tests for neuraminidase production would be a valuable addition to biochemical tests currently used in taxonomic studies of the Bacteroidaceae.

Bacteroidaceae↗
PubMed1975

Preparation of a glycoprotein fraction from pooled human plasma and its evaluation as a substrate for the assay of Clostridium welchii (C. perfringens) neuraminidase.

A glycoprotein fraction (fraction VII) suitable for use as a substrate in assays of microbial neuraminidase was prepared from pooled human plasma. It is pasteurised during preparation to eliminate the risk of transmission of serum hepatitis. This results in polymerisation of some of the gamma1-acid glycoprotein, but fraction VII is shown to be an excellent substrate for the neuraminidase of Clostridium welchii (C. perfringens). A sensitive assay procedure is described. A number of factors may interfere with the measurement of NANA released by the action of microbial neuraminidase and procedures are described for evaluation of this problem. Fraction VII is easy to prepare, cheap and available in standard form in large amounts (inquiries should be addressed to J. K. S.); it is recommended for routine use as a convenient substrate for neuraminidase assays.

Clostridium perfringens↗
PubMed1975

The production of neuraminidase by food poisoning strains of Clostridium welchii (C. perfringens).

The production of neuraminidase by a classical strain of Clostridium welchii (C. perfringens) type A was studied. Good yields were produced in 5% Proteose Peptone-water medium (PPW5); the enzyme was essentially extracellular but some further neuraminidase could be released by ultrasonic disintegration of the cells. This also released N-acyl neuraminic acid-aldolase (NAN-aldolase) and the degree to which this interferes with the assay for neuraminidase was evaluated. Forty-one British reference food-poisoning strains of C. welchii type A were examined for extracellular neuraminidase production in PPW5. Twelve of 17 strains that produce so-called heat-sensitive spores were neuraminidase positive whereas 20 of 24 strains that are non-haemolytic and produce very heat-resistant sporeswere neuraminidase negative. Variation was found in the ability to produce neuraminidase among strains of a single Hobbs' serotype; four Hobbs' type-13 strains produced neuraminidase but a fifth did not. Disruption of the cells of a Hobbs' type-2 strain that did not produce any extracellular neuraminidase released NAN-aldolase but there was no evidence of cell-associated neuraminidase. British food-poisoning strains of C. welchii type A thus include some that are clearly neuraminidase positive and some that still cannot be shown to produce neuraminidase. There is no correlation between lack of neuraminidase production and the ability to cause food poisoning, although the majority of non-haemolytic heat-resistant strains do not produce neuraminidase. It remains possible that neuraminidase may play a part in C. welchii gas gangrene; it is suggested that the ability to define neuraminidase-negative strains may now be of value in investigating this possibility.

Clostridium perfringens↗
PubMedDate not supplied

Transesophageal echocardiographic demonstration of resolution of mitral vegetations after warfarin in a patient with the primary antiphospholipid syndrome.

A 16-year-old girl with multiple cerebral infarcts was reported to have a normal transthoracic echocardiogram, but transesophageal echocardiography revealed vegetations on the atrial surfaces of both mitral leaflets at their line of closure. Blood cultures were negative, and prolonged treatment with intravenous antibiotics produced no echocardiographic improvement in the appearance of the vegetations. A diagnosis of primary antiphospholipid syndrome was made subsequently, although test results for this condition had initially been normal. Serial transesophageal echocardiograms showed complete resolution of the vegetations but some persistent thickening of the mitral leaflets, after warfarin therapy for 9 months. We suggest that in patients with culture-negative endocardial vegetations, specific tests should be performed for the primary antiphospholipid syndrome and a therapeutic trial of warfarin should be undertaken before contemplating heart surgery.

Adolescent↗
PubMedDate not supplied

Severe mitral regurgitation caused by immobile posterior leaflet after radiotherapy.

Radiotherapy may affect the heart in several ways. We describe a child who had pulmonary edema caused by severe mitral regurgitation after thoracic radiotherapy for a Ewing sarcoma. Transesophageal echocardiography demonstrated this to be caused by an immobilized posterior leaflet, and valve replacement was necessary. This is the first reported patient with rapid progression to severe valvar disease after radiotherapy and in whom this novel mechanism has been demonstrated.

Bone Neoplasms↗
PubMedDate not supplied

Intraoperative transesophageal versus epicardial ultrasound in surgery for congenital heart disease.

Twenty-eight patients (age range, 0.7 to 65 years; median age, 6.1 years) who were undergoing correction for congenital heart disease were entered into a prospective study with both intraoperative transesophageal and epicardial ultrasound to determine the relative values of these techniques before and after bypass surgery. Introduction of the transesophageal probe was successful in 26 patients (93%); children were studied with use of dedicated pediatric transducers. Epicardial studies were performed in all 28 patients. Epicardial studies allowed for higher resolution imaging and a more complete assessment before bypass surgery of the intracardiac morphological condition (ventricular septum and right ventricular outflow tract) than the assessment that was obtained by the transesophageal approach. In the period immediately after bypass surgery, the transesophageal technique allowed a more detailed insight into atrioventricular valve function (valvar regurgitation [five patients] and ventricular inflow patterns) and the continuous monitoring of left ventricular function and volume. Residual interventricular shunting (three patients) or residual outflow tract obstruction (four patients) could not be reliably documented by transesophageal studies. It is concluded that intraoperative transesophageal and epicardial ultrasound in surgery for congenital heart disease are complementary rather than alternative techniques.

Adolescent↗