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Biomedical subjects

D Wakefield

Publications and source records attributed to D Wakefield.

At least 109 records · Page 6Linked to original sources
PubMed1993

Functional activity of plasma fibronectin in patients with diabetes mellitus.

Decreased wound healing and increased infection are major problems in patients with diabetes mellitus. Fibronectin plays a fundamental role in wound healing and acts as an opsonin for the phagocytosis of foreign antigens. The aim of this study was to ascertain the functional activity of plasma fibronectin from patients with diabetes mellitus. Initially, a modified Boyden chamber technique was used to measure cell migration on fibronectin purified from patient's plasma and an enzyme-linked immunosorbent assay was used to measure the binding of gelatin. A sandwich assay was developed that enabled the capture of fibronectin directly from patient's plasma without prior purification. With the use of a 96-well format, the binding of two different monoclonal antibodies could be compared simultaneously with the binding of gelatin and cell adhesion. In this way, differences in the function of particular domains of fibronectin from diabetic patients and control subjects could be measured. Results showed no difference between fibronectin from diabetic patients and control subjects with respect to the monoclonal antibodies binding in 1) the cell adhesion domain and 2) the heparin-binding domain. Furthermore, no detectable differences were noted with respect to cell adhesion, cell migration, or gelatin binding. These results suggest that diabetic patients receiving insulin treatment show no modulation of plasma fibronectin function, despite raised levels of circulating glucose.

Adolescent↗
PubMed1993

Production of a functional single-chain Fv fragment from the pan-leukocyte antibody WM65 using splicing by asymmetric PCR.

A method of assembly of a single-chain Fv fragment is described, whereby asymmetric polymerase chain reactions (APCR) and primer extension were used to join immunoglobulin heavy and light chain variable region genes via a linker sequence. In this procedure heavy and light chain genes, together with a linker gene containing complementary sequences, were amplified by APCR to generate single-stranded products. The single stranded heavy or light chain genes were hybridized to the relevant single-stranded link product, and extended to produce double-stranded heavy-link and link-light genes. These genes then underwent another round of APCR, resulting in two single-stranded genes (heavy-link and link-light) containing extensive overlapping sequences. Hybridization and extension of these two single-stranded products allowed the formation of the complete heavy chain-link-light chain double-stranded product. Using this method, a functional single-chain Fv fragment based on the pan-leukocyte antibody WM65 was expressed and purified from E. coli. This method of immunoglobulin gene assembly by polymerase chain reaction (PCR) offers an alternative to the current methods of the genetic engineering of antibody fragments.

Antibodies↗
PubMed1992

Distribution of lymphocytes and cell adhesion molecules in iris biopsy specimens from patients with uveitis.

To investigate the mechanisms responsible for lymphocyte accumulation in the eye in uveitis, we examined iris biopsy specimens that were obtained from 10 patients with uveitis and from 12 patients with cataract for the presence of adhesion molecules on vascular endothelium, uveal cells, and infiltrating inflammatory cells. Immunoperoxidase staining of iris biopsy specimens that were obtained from patients with uveitis revealed an increased expression of intercellular adhesion molecule 1 (CD54) on endothelial cells, lymphocytes, fibroblasts, and iris epithelial cells. Seven of the 10 iris biopsy specimens that were obtained from patients with uveitis had a significant inflammatory cell infiltrate. Lymphocytes (CD2 positive) that infiltrated the iris were predominantly helper T cells (70%) and strongly expressed the lymphocyte function-associated antigen 1 (CD11a, CD18) molecule, the ligand for intercellular adhesion molecule 1, in four of the seven biopsy specimens. In contrast, small numbers of lymphocytes were evident in only three (25%) of the iris biopsy specimens that were obtained from patients with cataract. Vascular endothelium from the latter group did not express intercellular adhesion molecule 1 or endothelial leukocyte adhesion molecule 1. The results of this study revealed the enhanced expression of vascular endothelial cell and lymphocyte adhesion molecules in the iris biopsy specimens that were obtained from patients with uveitis. The presence of these receptors and their presumed ligands may have important implications for the role of these molecules in the pathogenesis of uveitis.

Adult↗
PubMed1992

The role of cytokines in the pathogenesis of inflammatory eye disease.

A coherent view of the role of cytokines in inflammatory eye disease is emerging as a result of studies both in man and experimental animals. Cytokines have been demonstrated in ocular tissue obtained from patients with intraocular inflammation (uveitis) (gamma interferon, IL-2) and have been shown to induce inflammation in experimental animals after intraocular injection [(IL-1, IL-6, IL-8, tumour necrosis factor (TNF), granulocyte macrophage-colony stimulating factor (GM-CSF)]. Several unique features of the immunology of the eye such as the immunosuppression associated with anterior chamber associated immune deviation (ACAID) may be due to the effects of cytokines. Similarly, common complications of ocular inflammation such as glaucoma, keratic precipitates, retinal (macular) oedema and neovascularization may be mediated by cytokines. Understanding of the role of cytokines in inflammatory eye disease has the potential to lead to the development of therapies to abrogate the effects of these important mediators of the inflammatory response.

Animals↗
PubMed1992

Cell-mediated immunity in patients with chronic fatigue syndrome, healthy control subjects and patients with major depression.

The chronic fatigue syndrome (CFS) is characterized by severe persistent fatigue and neuropsychiatric symptoms. It has been proposed that the abnormalities in cell-mediated immunity which have been documented in patients with CFS may be attributable to a clinical depression, prevalent in patients with this disorder. Cell-mediated immune status was evaluated in patients with carefully defined CFS and compared with that of matched subjects with major depression (non-melancholic, non-psychotic) as well as healthy control subjects. Patients with CFS demonstrated impaired lymphocyte responses to phytohaemagglutinin (PHA) stimulation, and reduced or absent delayed-type hypersensitivity (DTH) skin responses when compared either with subjects with major depression or with healthy control subjects (P less than 0.05 for each analysis). Although depression is common in patients with CFS, the disturbances of cell-mediated immunity in this disorder differ in prevalence and magnitude from those associated with major depression. These observations strengthen the likelihood of a direct relationship between abnormal cell-mediated immunity and the etiology of CFS.

Adolescent↗
PubMed1992

Vascular endothelium and lymphocyte adhesion molecules in minor salivary glands of patients with Sjogren's syndrome.

The aim of this study was to examine the distribution and types of adhesion molecules expressed over endothelial cells and the ligands present on lymphocytes which infiltrate exocrine glands in patients with Sjogren's syndrome. Minor salivary gland biopsies were examined from twelve patients with Sjogren's syndrome and eight normal subjects for the presence of adhesion molecules using monoclonal antibodies and an Indirect Immunoperoxidase technique. There was an increased expression of intercellular adhesion molecule-1 (ICAM-1, CD54) on endothelial cells, lymphocytes, fibroblasts and salivary gland epithelial cells. In addition we documented the expression of endothelial leukocyte adhesion molecule-1 (ELAM-1) on endothelial cells in salivary glands from patients but not the controls. Many of the endothelial cells expressing these adhesion molecules in patients with Sjogren's syndrome had the morphological appearance of high endothelial venules. V-CAM-1 was shown to be present in some of the salivary biopsies from patients with Sjogren's syndrome. Lymphocytes infiltrating salivary glands strongly express LFA-1 (CD11a/CD18) molecules. Some infiltrating lymphocytes, and most monocytes, expressed C3bi-R (CD11b/CD18) and the p150.95 (CD11c/CD18) antigens on their cell surface. The results of this study reveal the enhanced expression of vascular endothelial and lymphocyte adhesion molecules on the minor salivary glands of patients with Sjogren's syndrome. The presence of such receptors and their putative ligands indicate an important role for these molecules in the pathogenesis of Sjogren's syndrome.

Adult↗
PubMed1992

Endothelial leukocyte adhesion molecule-1 in endotoxin-induced uveitis.

Expression of endothelial leukocyte adhesion molecule-1 (ELAM-1) on endothelial cells leads to the attachment of polymorphonuclear leukocytes. The sequential expression of ELAM-1 and major histocompatibility complex (MHC) class II antigen was examined in the eyes of 59 Lewis rats with endotoxin-induced uveitis (EIU) after the injection of Salmonella typhimurium endotoxin. The eyes were enucleated at 2-hr intervals. Hematoxylin and eosin-stained paraffin-embedded sections and immunohistochemically stained cryostat sections were graded by two masked observers. The MHC class II antigen was expressed on cells in the iris and ciliary body 4 hr after injection of endotoxin and on the corneal endothelium, 8 hr postinjection. It was found that ELAM-1 was expressed first on cells of the ciliary body and iris 10 hr after the injection of endotoxin and on the corneal endothelium, 22 hr postinjection. Clinical and histopathologic disease developed 16 hr postinjection. Adherence of polymorphonuclear cells to the corneal endothelium was observed at the time of ELAM-1 expression. In conclusion, expression of ELAM-1 on ocular tissue occurred in EIU and appeared to promote polymorphonuclear cell accumulation in the anterior segment of the eye.

Animals↗
PubMed1992

Tumor necrosis factor-alpha in advanced HIV infection in the absence of AIDS-related secondary infections.

The effect of HIV infection on the production of tumor necrosis factor-alpha (TNF-alpha) was examined in patients with advanced human immunodeficiency virus (HIV) infection in the absence of AIDS-related secondary infections. Serum TNF-alpha and TNF-alpha production in vitro were measured by enzyme-linked immunosorbent assay in 26 male homosexuals with CDC stage IV HIV infection without active AIDS-related secondary infections. In vitro TNF-alpha production was assayed from cultured peripheral blood mononuclear cells (PBMs) or whole blood cultures under conditions for minimising endotoxin contamination. PBMs and whole blood were cultured with and without lipopolysaccharide (LPS). Results were compared with those for 13 HIV-seronegative age- and sex-matched controls. Serum TNF-alpha concentrations were 5 +/- 16 pg/ml in HIV-infected patients and 12 +/- 17 pg/ml in controls. TNF-alpha levels in unstimulated cultures of PBMs obtained from patients were 426 +/- 511 pg/ml and 456 +/- 428 pg/ml in control cultures. There was no difference between groups in the maximal responses of cultured PBMs to stimulation with LPS (2,229 +/- 1,593 pg/ml vs. 2,504 +/- 961 pg/ml). TNF-alpha levels from unstimulated and LPS-stimulated whole blood cultures were not significantly different after adjusting for the number of cultured monocytes (2,038 +/- 1,469 pg/ml vs. 1,511 +/- 488 pg/ml). In 10 patients (38%) the TNF-alpha levels from stimulated whole blood cultures were greater than the 95% confidence interval of the control group. TNF-alpha levels in patients were not significantly altered by antiretroviral therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Opportunistic Infections↗
PubMed1992

Immunological and psychological dysfunction in patients receiving immunotherapy for chronic fatigue syndrome.

Associations between immunological and psychological dysfunction in 33 patients with Chronic Fatigue Syndrome (CFS) were examined before and in response to treatment in a double blind, placebo-controlled trial of high dose intravenous immunoglobulin. Only those patients who received active immunotherapy demonstrated a consistent pattern of correlations between improvement in depressive symptoms and markers of cell-mediated immunity (CMI). This finding lends some support to the hypothesis that depressive symptoms in patients with CFS occur secondary to, or share a common pathophysiology with, immunological dysfunction. This pattern and the lack of strong associations between depression and immunological disturbance prior to treatment are less supportive of the view that CFS is primarily a form of depressive disorder or that immunological dysfunction in patients with CFS is secondary to concurrent depression.

Adolescent↗
PubMed1991

Prediction of response to treatment in patients with scleritis using a standardised scoring system.

Scleritis is a severe chronic inflammation of the eye wall. High-dose corticosteroids and other immunosuppressive drugs are often required to control the inflammatory process. With the development of new and potentially more effective treatment modalities for scleritis has emerged the need for an accurate and reproducible system for quantifying the severity of scleritis and evaluating the response of individual patients to treatment. We have developed a quantitative scoring system, based on common clinical signs of scleritis, and evaluated it in 24 patients with scleritis. Our results indicate that this system is simple, rapid, reproducible and useful in grading the severity of scleritis and in predicting the response of patients to systemic immunosuppressive therapy.

Adolescent↗
PubMed1991

Cyclosporine: a therapy in inflammatory eye disease.

Severe uveitis is a relatively common and difficult clinical management problem in ophthalmology. Recently, cyclosporine-A (Cs-A) has been shown to be of therapeutic benefit in the management of sight threatening inflammatory eye disease. In order to examine the efficacy and long term safety of Cs-A, we conducted an open uncontrolled study in 22 patients with sight threatening uveitis whose disease had previously been refractory to treatment with systemic corticosteroids (22 patients), azathioprine (5 patients) and cyclophosphamide (2 patients). Uveitis was idiopathic in 16 cases, one patient had Reiter's syndrome, two had Vogt Koyanagi Harada disease and one patient had sarcoidosis. There were twelve males and ten females with a mean age of 40.5 years (range 22-67 yrs). Nineteen patients (86%) showed significant clinical improvement after treatment with Cs-A (10 mgm/kg/day) with decreased inflammatory activity and improved visual acuity. Three patients failed to respond to Cs-A therapy, while 4 subjects whose disease had initially responded to Cs-A relapsed on attempted withdrawal of this medication. Side effects were common in patients receiving Cs-A [5 mgm/kg/day (or greater)], with hypertension, tremor, hirsutism and raised serum creatinine being most frequent. We conclude that CS-A is an effective immunosuppressive agent in the treatment of patients with uveitis; however, its usefulness is limited by frequent side effects and disease relapse on attempted drug withdrawal.

Adult↗
PubMed1991

Dilemmas surrounding the identification of essential rural hospitals.

Criteria are needed for use in designating some rural hospitals as essential so that they may receive state or federal assistance. Three types of criteria are considered in this analysis: hospital volume measures, hospital competitiveness measures, and community need measures. The criteria sets reflect different assumptions about the relationship between need and demand for health services. Analysis of available data reveals that neither hospital volume nor competitiveness is correlated with community need, meaning that different hospitals would be designated as essential under each system. Implications are discussed.

Bed Occupancy↗
PubMed1990

Prevalence of chronic fatigue syndrome in an Australian population.

An epidemiological study was undertaken to provide the first reported estimate of the point prevalence of chronic fatigue syndrome in an Australian community. After a pilot study in a separate location, the population of the Richmond Valley, New South Wales, was sampled using a structured case-finding technique, which included notification from local medical practitioners, the use of a screening questionnaire and standardised interviews conducted by a physician and psychiatrist. In addition, investigations were performed to exclude alternative diagnoses and to assess cell-mediated immunity. Forty-two patients with chronic fatigue syndrome, with a female:male ratio of 1.3:1.0, were detected in a population of 114,000. The mean age at onset of symptoms was 28.6 years (SD, 12.3 years), and the median duration of symptoms from onset to sampling date was 30 months. The social status of the patients was distributed in accordance with that of the remainder of the population sampled, with no bias towards the middle or upper social classes. The disorder was causing considerable incapacity, with 43% of patients unable to attend school or work. The conservative estimate from this study suggests a prevalence on June 30 1988 of 37.1 cases per 100,000 (95% confidence interval [CI], 26.8-50.2). Chronic fatigue syndrome is an important disorder in this Australian community that affects young individuals from all social classes and causes considerable ill health and disability.

Activities of Daily Living↗