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Biomedical subjects

P Davis

Publications and source records attributed to P Davis.

At least 379 records · Page 21Linked to original sources
PubMed1983

Superoxide production in neutrophils of patients with rheumatoid arthritis and Felty's syndrome.

The production of superoxide by N-formylmethionyl-leucyl-phenylalanine activated neutrophils was measured prospectively with a ferricytochrome C reduction assay in 33 normals, 33 patients with rheumatoid arthritis and 9 patients with Felty's syndrome. Both the rate and quantity of superoxide production were significantly lower in patients with Felty's syndrome when compared to the other 2 groups. This finding suggests a possible additional factor in the increased propensity of these patients to develop infections.

Arthritis, Rheumatoid↗
PubMed1983

Prevalence of eosinophilia during gold therapy for rheumatoid arthritis.

The prevalence of eosinophilia in 82 rheumatoid arthritis patients receiving gold sodium thiomalate (GSTM) and 30 patients receiving auranofin (AF) was determined in a retrospective study. Eosinophilia occurred in 21% taking GSTM and in 13% on AF. The simultaneous occurrence of toxicity and eosinophilia occurred in 14% receiving GSTM and in 10% receiving AF. In contrast, eosinophilia only occurred in 24% of those with suspected toxicity receiving GSTM and in 30% of those with suspected toxicity receiving AF. The value of eosinophilia as a marker of toxicity is discussed.

Adult↗
PubMed1983

Absence of circulating immune complexes containing DNA in hemodialysed sera.

Although the presence of free DNA and antibodies to DNA in the sera of patients on maintenance hemodialysis has been reported, we found only a low incidence of antibodies to single-stranded DNA (ss-DNA) and native DNA (n-DNA) using an improved detection technique. In our search for evidence of the possible formation of DNA-anti-DNA circulating immune complexes (CIC), antibodies to n-DNA were detected in the sera of only 2 of 53 dialysed and 1 of 25 non-dialysed renal patients. CICs were detected in the sera of 17 of 53 dialysed (28% by Raji-RIA, 6% by Clq-BA) and 6 of 25 non-dialysed (20% by Raji-RIA and 24% by Clq-BA) renal patients: the difference is not significant (P greater than 0.25). DNase digestion of the dialysed sera that were positive for CIC by Raji-RIA produced no significant change in the results on re-assay (P greater than 0.50) in contrast with a significant decrease in CIC after DNase digestion of selected SLE sera and of solutions containing DNA-anti-DNA complexes formed in vitro (P less than 0.05). The formation of circulating DNA-anti-DNA complexes appears not to be the cause of the low incidence of antibodies to n-DNA in the sera of dialysed patients.

Antibodies↗
PubMed1982

Neutropenia in rheumatoid arthritis: studies on possible contributing factors.

Twenty-five patients with rheumatoid arthritis (RA) and neutropenia, of whom 19 had a palpable spleen, were compared with 24 patients with uncomplicated RA, and 16 patients with RA and associated splenomegaly without neutropenia. Clinically patients with neutropenia had evidence of a more systemic disease as assessed by prevalence of rheumatoid nodules, weight loss, and recurrent infections. However, there was less evidence of active synovitis than in the other 2 groups. Marrow neutrophil reserve was studied by means of a hydrocortisone stimulation test and was found to be lower in all 3 groups than in normal persons but with most marked depletion in the neutropenic group. Removal of the spleen in some patients with neutropenia resulted in a significant increase in marrow neutrophil reserve. Circulating immune complexes as detected by anticomplementary activity and platelet aggregation tests were detected in 68% of the RA neutropenia group, 31% of the RA splenomegaly group, and 8% of the uncomplicated RA group. Our results show that, assessed both clinically and by the above tests, patients with neutropenia have a greater prevalence of abnormalities which may be directly related to their neutropenia. Patients with splenomegaly alone closely resemble patients with uncomplicated RA.

Agranulocytosis↗
PubMed1982

Converting the need for care into demand for services.

Two strategies for converting need into demand are identified. One, a longer term programme, involves raising the level of 'want', or perceived need, through attitude change. The other has a more immediate impact and involves increasing the rate at which perceived needs are converted into demands by reducing organizational barriers. It is argued that, potentially, a quarter of the adult population is susceptible to demand expansion under the second strategy. Although racial and social class differentials in perceived need would be unaffected by such a programme, inequality in demand would be reduced. A number of quite specific initiatives are suggested. First, the retentiveness of the dental system can be increased, especially among marginal groups, through the establishment of a more egalitarian clinical relationship, by the exercise of human relationship skills, through behavioural strategies for increasing compliance and through improved access. Secondly, improved geographical access can be achieved through tapping the 'captive' populations present in two major institutional areas, the school and the work site. This requires mobility in deployment of resources and flexibility in negotiating the organization and financing of care. Finally, more rational visit schedules, organizational arrangements and payment systems need to be developed in the average dental practice.

Adult↗
PubMed1982

Energy costs of walking in lower-extremity plaster casts.

The energy cost of walking with axillary crutches and each of three types of plaster casts (long, short, and cylinder) on the lower extremity was measured in twenty normal adult men. The knee and ankle joints were immobilized unilaterally in the neutral positions. Oxygen uptake was measured using a modified Douglas-bag technique. Heart rate, respiratory rate, and step frequency were telemetered from transducers that were attached to the subjects. When walking and bearing full weight on a cast without the use of crutches, the average rates of energy expenditure for subjects wearing the three varieties of casts did not significantly differ from the value for normal walking. Velocity, however, was reduced depending on the extent of immobilization. The average velocity of the subjects was fifty-six meters per minute in a long cast, sixty-four meters per minute in in a cylinder cast, and seventy meters per minute in a short cast, compared with seventy-eight meters per minute without immobilization of the limb. The subjects' average oxygen cost per meter was 0.24 milliliter per kilogram in a long cast, 0.20 milliliter per kilogram in a cylinder cast, and 0.19 milliliter per kilogram in a short cast, compared with 0.15 milliliter per kilogram for normal walking. Using a unilateral non-weight-bearing swing-through gait, the average rate of oxygen uptake for subjects wearing the three types of casts did not differ from the mean value without a cast (21.2 milliliters per kilogram per minute). All values were at least 60 per cent higher than the average for normal level walking.

Adult↗
PubMed1981

Relationship between serum ferritin, anemia, and disease activity in acute and chronic rheumatoid arthritis.

The assessment of anemia in patients with rheumatoid arthritis may be difficult, especially when iron deficiency and the anemia of chronic disease coexist. The development of a radioimmunoassay for serum ferritin concentration has aided the detection of reduced body iron stores in uncomplicated iron deficiency, but its use is compromised in clinically active rheumatoid arthritis by the tendency of serum ferritin to behave as an acute phase reactant. In this latter role it correlated well with disease activity in the patients we studied. Followed serially, serum ferritin levels fell in patients whose disease activity improved after institution of appropriate therapy. In anemic patients with clinically inactive disease, supplemental iron was associated with a significant rise in hemoglobin when compared to untreated patients. Serum ferritin levels behaved independently of hemoglobin levels. Therefore even in clinically inactive rheumatoid arthritis, serum ferritin does not accurately reflect an iron deficiency.

Adult↗
PubMed1981

Radionuclide bone scanning in females with chronic low back pain.

Sixty female patients with chronic low back pain have been studied clinically, radiographically, and by radionuclide bone scanning for evidence of sacroiliac disease. Twenty-four patients had quantitative sacroiliac scintigraphy (QSS) results suggesting sacroiliitis. In only one of these patients was the radiograph abnormal. Clinical and laboratory examinations failed to reveal any possible associated aetiological factors. Six-month follow-up of 18 patients showed that subjective improvement of pain is associated with a return to normal of QSS results, often secondary to anti-inflammatory medication. It is concluded that sacroiliac disease may be a common cause for chronic low back pain in women and that its presence may be missed if radiographs are relied upon to confirm the diagnosis. Its aetiology remains obscure.

Adolescent↗
PubMed1981

Nuclear magnetic resonance imaging of the abnormal live rat and correlations with tissue characteristics.

Nuclear magnetic resonance (NMR) images of live rats with sterile and pyogenic abscesses, hematomas, and various implanted and spontaneous neoplasms demonstrated good contrast differentiation between pathologic and surrounding normal tissues. This differentiation was maximal when both the T1 and T2 tissue relaxation times were used as criteria. Neoplasms have a broad range of T1 and T2 values and may be confused with abscesses or hematomas. Tissue rate constants (1/T1 and 1/T2) are mainly dependent on total water content, the exception being fat, which has a 1/T2 value much shorter than that expected on the basis of water content alone.

Abscess↗
PubMed1981

Effect of gold salts on peripheral blood monocytes and macrophages.

Gold salts have a number of actions at a cellular level which theoretically could either independently or in combination result in the suppression of the inflammatory response leading to the characteristic remission seen in patients receiving chrysotherapy for rheumatoid arthritis. Gold salts have a number of effects on peripheral blood monocyte and macrophage invasion of inflammatory sites as suggested by their ability to inhibit macrophage migration in response to known chemotactic factors. Once present within an inflammatory site, the presence of gold ions may inhibit both the ingestion and digestion of particulate matter, as suggested by both the in vivo and in vitro studies on phagocytic activity of macrophages exposed to gold salts. Finally, they may also be responsible for a reduction in antigen processing and their capability to interact with T-lymphocytes in the mediation of cell-mediated immune responses to appropriate antigenic stimuli.

Animals↗
PubMed1981

An evaluation of methods for the purification of DNA preparations.

Four tritiated thymidine-labeled DNA preparations known to contain areas of single strandedness were chromatographed on BNDC, HAP, and MAK. With an ethidium bromide fluorescence technique, the proportion of single-stranded regions in each of the stock preparations and DNA column eluates was evaluated. Although all column methods removed a significant proportion of test material containing single-stranded DNA, only MAK columns consistently yielded homogeneous double-stranded DNA preparations. Variable results were obtained, depending on the preparation chromatographed and the method used. Millipore filtration, although reducing single-stranded contamination, also failed to produce uniformly double-stranded DNA. Serum anti-DNA bindings were measured by the Millipore filter technique with two DNA preparations before and after chromatography. A significant decrease in percent binding was demonstrated with DNA samples fractionated on MAK columns as a result of the removal of most single-stranded DNA regions. Only select sera tested against BNDC and HAP DNA eluates showed a decrease in anti-DNA binding. It is concluded that methods of column chromatography are variably effective in reducing the proportion of single-stranded DNA in mixed DNA preparations. Confirmation of the homogeneous nature of the DNA antigen by structural analysis is recommended.

Animals↗