Biomedical subjects

P Davis

Publications and source records attributed to P Davis.

At least 415 records · Page 23Linked to original sources

PubMed1978

Quantitative sacroiliac scintigraphy in patients with Crohn's disease.

Sixty patients with Crohn's disease have been assessed radiologically and by quantitative sacroiliac scintigraphy for evidence of sacroilitis and/or ankylosing spondylitis. The incidence of radiologic sacroiliitis (11%) and ankylosing spondylitis (5%) was no greater in our series than previously reported. However, the incidence of increased uptake of radiotracer at the sacroiliac joints was 52%. There was no correlation in the group as a whole between radiologic and/or scintigraphic evidence of sacroiliitis and the tissue antigen HLA-B27.

Adolescent↗

PubMed1978

Analysis of DNA structure by hydroxyapatite columns and ethidium bromide fluorescence techniques. A comparative study and effect on DNA binding.

Seven duplex DNA preparations have been structurally analyzed by hydroxyapatite column chromatography and an ethidium bromide fluorescence technique. Significant contamination of one preparation with single-stranded DNA was detected by hydroxyapatite column chromatography. Five of the other six preparations were found to contain significant single-stranded regions by the ethidium bromide fluorescence technique. Synthetic poly dAT was found to be duplex in structure. The presence of single-stranded regions considerably influenced DNA binding results in a radioimmunoassay.

Antibodies↗

PubMed1978

New method of treatment of immune infertility.

A history is presented of a couple suffering from long-standing infertility, which on laboratory investigation was found to be immunologic infertility, as expressed in the male partner. This case of male infertility was diagnosed by findings of sperm antibody in both the serum and the seminal plasma of the man, using both the Kibrick and the F-D sperm agglutination test methods. A new effort at treatment, by means of attempted immunosuppression, was proposed and applied, using corticosteroid medication. The special feature of this treatment involved a high dosage (96 mg. per day of methylprednisolone) for a short period (seven days). Laboratory studies revealed that the antibody levels, in both his serum and seminal plasma, did fall considerably. The wife became pregnant in the subsequent cycle. It is proposed that such diagnostic and treatment efforts be tried in other cases of male immunologic infertility.

Antibodies↗

PubMed1978

Immune infertility and new approaches to treatment.

A number of patients who have involuntary infertility show sperm antibodies in the blood serum, as detected by two quite different methods of spermagglutination. These techniques are the Kibrick method (gelatin agglutination test) and the F-D method (tube-slide agglutination test). By the former technique, the sera of 18% of women and 9% of men from infertile couples were found to be positive; by the latter technique, the sera of 15% of women and 5% of men were positive. Such cases are termed "immunologic infertility." In an effort to develop new methods for the treatment of infertility, two procedures were explored. One is a sperm washing insemination method in which fresh semen from a man with the antibody is centrifuged, resuspended in an albumin solution, and then used for insemination. The second is an immunosuppression method, using methylprednisolone at a dose of 96 mg/day for 7 days. A striking decrease in antibody level was seen in some cases, with ensuing pregnancy. The success rates for these methods have been of the order of 14% to 22%.

Antibodies↗

PubMed1978

The estimation of whole-body zinc and Zn turnover in rheumatoid and osteoarthritis using 65Zn tracer.

1. A method of estimating whole-body zinc, and Zn balances using a two-compartment model in combination with whole-body counting of 65Zn, is described. The method is applied to patients with rheumatoid and osteoarthritis. 2. The results suggested that there was not a wide variation in whole-body Zn and Zn turnover in individuals with these two diseases and no clearcut difference between patients with one or the other.

Adult↗

PubMed1978

Role of ultraviolet light and UV DNA in the induction of skin lesions in experimental animals.

In vivo and in vitro animal experiments have been performed to clarify the role of ultraviolet light denatured DNA (UV DNA) and ultraviolet light (UVL) in the pathogenesis of the dermal lesions of human SLE. Rabbits immunized with UV DNA show deposition of immunoglobulin at the dermal-epidermal junction following exposure to UVL. We have also shown that UV DNA appears concomitantly with the antibody at the dermal-epidermal junction subsequent to the UVL exposure. Both n DNA and UV DNA have been shown to bind to the dermal-epidermal junction in vitro which could result in the persistence of these antigens at this site. These studies lend further support to the hypothesis that the release of UV DNA and its subsequent deposition at the dermal-epidermal junction may result in binding of both immunoglobulin and complement, leading to the development of histological lesions of SLE.

Animals↗

PubMed1978

A longitudinal study of in vitro tests for lymphocyte function in rheumatoid arthritis.

In vitro tests of lymphocyte function have been performed in 61 patients with ;classical' or ;definite' rheumatoid arthritis. In vitro lymphocyte function was assessed by lymphocyte transformation responses to phytohaemagglutinin (PHA), Pokeweed mitogen (PWM), Candida antigen, and herpes simplex type I (HSV1). Follow up data were available after 6 months of treatment in 32 of these patients. Spontaneous lymphocyte transformation was assessed in all patients. Results obtained in patients with rheumatoid arthiritis were compared to those seen in a normal control population. Disease activity of patients with rheumatoid arthritis was assessed using standard clinical methods. Lymphocytes from patients with rheumatoid arthritis showed a similar degree of spontaneous transformation to that seen in normal subjects. In contrast, lymphocytes from patients with rheumatoid arthritis responded less well to PHA and Candida and HSV1 antigens when compared to normal patients. In patients with rheumatoid arthritis the response to PWM was markedly enhanced compared to normals. Clinical improvement was noted in 19 of the 32 patients seen at follow up, all of whom had received gold or penicillamine therapy. The abnormal responses of PHA and PWM seen before treatment became normal in those patients who improved clinically. The responses to Candida and HSV1 antigens not only returned to normal following treatment but were increased above those seen in normal controls. A statistically significant association was seen between clinical improvement and improvement of in vitro tests of lymphocyte function.

Antigens, Fungal↗

PubMed1978

Upper respiratory tract and aural flora of saturation divers.

The conditions of helium saturation diving promote the proliferation of Gram-negative bacterial species in the external auditory meatus of divers. These changes in flora occurred in the absence of operational diving, that is, no contact with water. The colonising bacteria were autogenous in origin and cross-colonisation was observed between divers. On return to normal atmospheric conditions the aural flora became predominantly Gram-positive again within 48 hours.

Atmospheric Pressure↗

PubMed1978

Effect of ultraviolet light on disease characteristics of NZB/W mice.

The development of antinuclear antiboides, proteinuria and cumulative mortality has been studied in four groups of NZB/W mice. Two groups were exposed to different amounts of ultraviolet light [UVL] and one group were bred and raised in total darkness. The fourth group served as a control. No significant difference was noted bwtween the groups in the development of antinuclear antibodies, proteinuria or in cumulative mortality. This study failed to show any major role of UVL as an environmental factor in the development of this disease.

Animals↗

PubMed1977

Prevalence of ankylosing spondylitis and HLA-B27 in a North American Indian population: a pilot study.

The value of an epidemiologic approach to the diagnosis of ankylosing spondylitis was assessed in a pilot study of an Amerind population. In 103 adult volunteers aged 20 to 42 years on a Cree reservation lumbar flexion and chest expansion were measured and HLA typing was performed on peripheral blood lymphocytes. Of the 14 subjects with HLA-B27, 2 had radiologic evidence of sacroiliitis but none could be said to have definite ankylosing spondylitis on clinical grounds.

Adult↗

PubMed1977

A comparative study of technics for the detection of antibodies to native deoxyribonucleic acid.

Antibodies to native DNA have been assessed by three separate radioimmunoassay methods: the Millipore filter technic, the Farr ammonium sulfate precipitation test, and a commercially available kit method. Although each method was found to be reliably reproducible, the different units by which results are expressed made comparison difficult because of the technical variations inherent in each test. The correlation between tests was, however, high. To allow for interlaboratory standardization, it is suggested that the assay method used be clearly specified. Results are best expressed in terms of mg of DNA bound per deciliter of test serum. It appears that the centrally standardized radioimmunoassay kit is the most convenient method by which these antibodies can be measured in routine laboratories.

Ammonium Sulfate↗

PubMed1977

Antibodies to UV DNA and photosensitivity.

Antibodies to ultraviolet light denatured DNA (UV DNA) have been measured in the sera of patients with systemic lupus erythematosus, discoid lupus erythematosus, and light sensitive skin lesions. Antibodies were found in significant levels in the patients with SLE but not in the other groups. It appears that although UV denaturation of dermal DNA occurs in vivo this is not sufficient to induce antibodies to UV DNA in patients with a normal DNA repair mechanism. This may not be the case in patients with SLE in whom a break in tolerance to Native (N-) DNA has already occurred and where antibody to N-DNA will cross react with UV DNA.

Antibody Formation↗

PubMed1977

Correlation between levels of DNA antibodies and clinical disease activity in SLE.

Sera were tested from 23 patients with systemic lupus erythematosus followed over a period of 1 to 5 years. Antibodies to native DNA were measured and correlated retrospectively with clinical evidence of disease activity. The overall degree of correlation between the presence of DNA antibodies and evidence of disease activity was good (P less than 0-001). Of 206 sera tested, only 4 had a normal DNA antibody at a time when significant clinical activity was noted. In contrast, 34 sera had mild to moderately raised DNA antibody levels at times of clinical remission. Although DNA antibodies are a useful investigation in the monitoring of disease activity, changes in therapy should not necessarily be made on DNA antibody levels alone.

Alberta↗

PubMed1977

Evaluation of a standardised assay for the measurement of antibodies to double-stranded (native) DNA.

A standardised commercially available radioimmunoassay kit for the detection of antibodies to native DNA (N-DNA) has been evaluated in clinical practice. This test system is shown to be a reliably reproducible method of detecting these antibodies. In addition, evaluation of the purity of the radiolabelled test antigen in this assay has shown it to be almost entirely double stranded (native) DNA with virtually no contamination with single stranded (denatured) DNA, and with few areas of single stranded breaks or ends in the duplex molecule. The inclusion of known standards and precise characterisation of the DNA has partially overcome variability in results and provides for interlaboratory standardisation which is lacking in the techniques used at present.

Antibodies, Antinuclear↗

PubMed1977

Relationship between anti-DNA antibodies complement consumption and circulating immune complexes in systemic lupus erythematosus.

Eighty-nine sera from nineteen patients with systemic lupus erythematosus (SLE) have been studied to determine the relationship between levels of DNA-binding activity, complement consumption and evidence of circulating immune complexes. There was a good correlation between the height of DNA binding, a rising C3i and a reciprocal fall in C3, C4 and CH50 levels. These latter measurements provided useful supplemental information when studied serially. There was a good correlation between the results of the various methods used for the detection of circulating immune complexes, and these were found in almost half the sera with DNA binding over 70%. It is concluded that serial studied of DNA binding, complement levels, and direct tests for immune complexes, may provide valuable information in the management of patients with SLE.

Antibodies, Antinuclear↗

PubMed1977

Immunofluorescent technique for the detection of antibodies to n-DNA: comparison with radioimmunoassay.

One hundred and six sera from patients with systemic lupus erythematosus (SLE), 20 from patients without SLE but with a positive FANA, and 50 controls were tested for the presence of antibodies to n-DNA, using an immunofluorescent technique with the kinetoplast of Crithidia luciliae as a substrate. A high degree of correlation existed between the results obtained with this technique and a Millipore radioimmunoassay method using a well characterized tritiated native human DNA. The result with the immunofluorescent method could be expressed semiquantitatively as a titer, if serial serum dilutions were used. Results in patients with SLE correlated well with disease activity. We conclude that the immunofluorescent technique can provide a useful alternative to a radioimmunoassay for the detection of antibodies to n-DNA. In addition, as this substrate is known to contain pure n-DNA, problems do not arise with contamination with singlestranded DNA as sometimes occurs with other test antigens. This avoids the detection of antibodies reacting only with single-stranded areas and consequently increased the specificity of the reaction.

Antibodies, Antinuclear↗

PubMed1977

Serum ferritin levels in anemia of rheumatoid arthritis.

Thirty-five anemic patients with rheumatoid arthritis were studied to determine the relationship between serum ferritin levels and body iron status, as assessed by the grading of bone marrow iron stores. The incidence of greatly reduced or absent marrow iron stores was 60%. Peripheral blood smear, RBC indices, serum iron, and iron binding capacity correlated poorly with stainable marrow iron. Serum ferritin levels only correlated approximately with iron stores, and in iron deficient rheumatoid patients the levels were higher than would be expected in patients with uncomplicated iron deficiency. The study shows that reduced marrow iron stores is common in patients with rheumatoid arthritis, and that the serum ferritin concentration may provide a useful indication of reduced body iron stores in these subjects, but only if a range of normal values can be established for this disease.

Adult↗

PubMed1977

The sacroiliitis of acute Reiter's syndrome.

Sacroiliitis can be demonstrated radiologically in over one-third of patients with chronic Reiter's syndrome. We have used a bone scan technique with digital analysis which will quantitatively assess the sacroiliac joints, and have found abnormalities in 24 of 33 patients with active Reiter's syndrome. It seems likely therefore that sacroiliitis is a common feature in patients with early Reiter's syndrome and while in most patients it resolves with resolution of disease activity, in some it may persist with the development of overt radiological changes.

Acute Disease↗