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Biomedical subjects

S Dawson

Publications and source records attributed to S Dawson.

At least 145 records · Page 8Linked to original sources
PubMed1991

Right atrial catheters in children with cancer: a decade of experience in the use of tunnelled, exteriorized devices at a single institution.

In the period 1980-1988, data were collected (prospectively from 1985) on the clinical utilization of exteriorized, tunnelled, right atrial catheters in children with cancer undergoing treatment at a single institution. A total of 231 devices were placed in 180 patients. Individual catheters were in place for a median of 314 days, with a total experience of more than 83,000 days. This form of long-term venous access was used for the administration of antineoplastic agents and other drugs, blood products (especially platelet concentrates and packed red blood cells), parenteral nutrition and infusion of other fluids, obtaining samples of venous blood, and giving intravenous contrast media and radiolabeled substances for radiological investigations. Almost 80% of catheters were removed electively (on completion of scheduled therapy or at death), with the remainder requiring removal in the management of infection or device displacement. Infections were manifest in two-thirds of the children, most commonly (60%) at the catheter exit site on the anterior chest wall. "Clinically significant" infection occurred with a frequency of 2.1 episodes per 1,000 patient days, with Staphylococcal species predominating except for the circumstances of catheter colonization in which Gram-negative, waterborne organisms were most in evidence. Empirical, intravenous, combined antibiotic therapy was effective in approximately 90% of "clinically significant" episodes. Mechanical complications (traveling, leakage, or catheter occlusion) occurred less frequently and were managed by repairing or replacing the device, or clearing the block. Indwelling catheters, of the Broviac or Hickman types, offer major advantages with acceptable morbidity in the management of children with malignant diseases.

Adolescent↗
PubMed1990

Neutralisation patterns among recent British and North American feline calicivirus isolates from different clinical origins.

The neutralisation patterns of 103 recent isolates of feline calicivirus from cats with chronic stomatitis or acute feline calicivirus disease, and from cats with neither oral nor respiratory disease were compared. There were no statistically significant differences between the proportions of isolates from each clinical source neutralised by individual feline calicivirus cat antisera. Different antisera showed widely differing degrees of cross reactivity; antisera to the most widely used vaccine strain F9 being the most cross reactive, neutralising 54 per cent of all the field isolates, and antisera to a field isolate LS015 the next most cross reactive, neutralising 29 per cent of the field isolates. However, the cross reactivity of antisera to early British isolates (A4, 68/40 and 69/1112) was much reduced (overall less than 10 per cent) whereas in the early 1970s 65 per cent of 117 field isolates from clinically normal cats were neutralised by A4 antiserum, and 40 per cent by each of 68/40 and 69/1112 antisera. This suggests a change in the spectrum of antigenicity among feline calicivirus isolates over the past 15 years. However, the cross reactivity of F9 antisera appeared to be similar to that in earlier studies. The relevance of these findings to vaccination is discussed.

Animals↗
PubMed1990

Genetic variation on chromosome 16 is associated with abdominal aortic aneurysm.

1. There is a familial tendency to abdominal aortic aneurysms. We have followed up a previous report of a weak association between the haptoglobin 2-1 phenotype and aortic aneurysm and investigated polymorphisms of the haptoglobin gene and neighbouring cholesterol ester transfer protein gene on the long arm of chromosome 16 in patients with atherosclerotic abdominal aortic aneurysm, patients with stenosing aortic atherosclerosis and healthy control subjects. The protein polymorphism of haptoglobin results from variant alpha-chains, alpha 1 and alpha 2, the phenotype nomenclature describing the two alpha-chains. We have also investigated whether the different haptoglobin phenotypes influence the degradation of aortic connective tissue. 2. The frequency of the haptoglobin alpha 1 allele was increased in patients with aneurysms compared with healthy control subjects (0.51 versus 0.35, P less than 0.05). Patients homozygous for the alpha 2 allele had the highest mean age at aneurysm resection. The frequency of a rare polymorphism at the cholesterol ester transfer protein locus was also increased in aneurysm patients (0.15 versus 0.05 in control subjects, P less than 0.01). These two genetic markers appear to act independently. Haptoglobins containing an alpha 1-chain accelerated two- to four-fold the degradation by elastases of aortic elastin in vitro. 3. Genetic variation in the haptoglobin and cholesterol ester transfer protein genes appears to influence dilatation of the abdominal aorta. Variation at the haptoglobin locus could have a direct effect on the degradation of elastin in atherosclerotic aorta, whereas variation at the cholesterol ester transfer protein locus could affect lipid metabolism and promote atherosclerosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Production of antiserum to a non-structural potyviral protein and its use to detect narcissus yellow stripe and other potyviruses.

A protein, of apparent molecular weight 72,000, was purified from experimentally infected narcissus plants with yellow stripe symptoms utilising SDS-polyacrylamide gel electrophoresis. This protein was excised from the gels and used to prepare antiserum, which reacted specifically with cytoplasmic cylindrical inclusions in ultra-thin sections of virus-infected cells and, in immunoblots, with the 72 kDa protein in preparations containing cytoplasmic inclusions. The antiserum reacted in ELISA with leaf extracts from yellow stripe diseased plants of four narcissus cultivars but not with extracts from comparable symptomless plants. In tests with extracts of plants infected with seven definitive potyviruses, reactions were obtained with bean yellow mosaic and iris mild mosaic viruses. Virus-specific reactions in dot-blot ELISA were dependent on the presence of Tween 20 in the extraction buffer. In contrast, an antiserum to the putative cytoplasmic inclusion protein of alstroemeria mosaic virus reacted only with SDS-treated leaf extracts of infected plants. In limited tests, the method of purifying cytoplasmic inclusion protein was successfully applied to four definitive potyviruses, suggesting that it may be generally applicable to potyviruses and of use for preparing antisera when purification of virus particles is difficult.

Antibodies, Viral↗
PubMed1989

Vero cell assay for rapid detection of Clostridium perfringens enterotoxin.

A rapid assay which measured the biological activity of Clostridium perfringens enterotoxin was developed. The method involved the rapid killing of Vero cells by enterotoxin produced by C. perfringens grown in Duncan and Strong sporulation medium. Serial dilutions of toxin were added to Vero cells either in suspension or grown as monolayers in wells of a 96-well cell tissue culture cluster plate. Vital staining of Vero cells with neutral red, followed by extraction of the dye, allowed toxin levels to be determined either visually or by optical density measurements with a micro-ELISA M580 computer program. The toxin produced was confirmed as different from the Vero toxin of Escherichia coli and the alpha and theta toxins of C. perfringens.

Animals↗
PubMed1989

Health care consumption and consumer social class: a different look at the patient.

Both the need and potential for market segmentation in the health care industry have grown substantially. Social class, a consumer behavior construct applied widely in other marketing contexts, may be useful as a basis for health care segmentation. Using a random sample of 997 households in the Pacific Northwest, the author investigates health care attitudes and behaviors across social class groups. Social class is found to be related positively and significantly to several aspects of health care, including personal health, interest, expenditures, satisfaction, and switching behavior.

Attitude to Health↗
PubMed1989

The Kingston project. I. Growth of malnourished children during rehabilitation in the community, given a high energy supplement.

Moderate and severely malnourished children referred from public health clinics in Kingston, Jamaica, to a metabolic ward were treated at home for 6 months using community health aides and standard health care similar to that offered by the local health service. A randomly selected subgroup of these children received in addition a daily high energy food supplement of 3.31 MJ for the first 3 months of the 6-month intervention period. Both groups received full nutritional and medical surveillance and care. The supplemented gained significantly more in weight than the unsupplemented children, but the advantage was lost once supplementation ceased. They also gained significantly more in length and this gain was maintained at the end of the intervention period. However, this increase in length, without continuing superior weight gain, left the supplemented children significantly more wasted than the unsupplemented, as measured by a body mass index (weight divided by height squared). These findings remained stable after interactions with morbidity measures had been taken into account. It is concluded that (1) high-energy supplementation assists rehabilitation of malnourished children brought to public health service clinics and treated in the community, and (2) supplementation should be continued until there is catch-up growth to within an acceptable distance from expected length for age.

Body Height↗
PubMed1988

Benign tertiary syphilis and HIV infection.

Benign tertiary (gummatous) syphilis has virtually disappeared [1]. Two homosexual men with gummata have presented to genitourinary medicine clinics in west London in recent months. They both had antibodies to HIV. It is possible that otherwise adequately treated syphilis has progressed to the tertiary stage as a consequence of HIV infection and modification of the immune response.

Acquired Immunodeficiency Syndrome↗