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Biomedical subjects

A Lloyd

Publications and source records attributed to A Lloyd.

At least 19 recordsLinked to original sources
PubMed1992

Synthesis of diacylglycerol analogues as potential second-messenger antagonists and inhibitors of protein kinase C.

A series of analogues of diacylglycerol has been prepared and tested as inhibitors of protein kinase C (PKC). The diketone analogues, 10-hydroxymethyl-8,13-eicosanedione (24), 10-acetoxymethyl-8,13-eicosanedione (25), and 10-methoxymethyl-8,13-eicosanedione (26) each inhibited PKC activated by 2-O-acetyl-1-O-oleoylglycerol. Compound 24 was the most effective inhibitor of the growth of MR4 and HT29 cells in culture, and 26 was more effective than 24 against HL60 cells.

Animals↗
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

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

Transformation suppressor activity of a Jun transcription factor lacking its activation domain.

The oncoprotein c-Jun is thought to be a mediator of ras transformation as both its synthesis and activity as a transcription factor are stimulated by ras expression. But c-Jun co-operates with ras in transformation assays, suggesting that they act along different pathways (reviewed in ref. 4). Here we show by means of a dominant-negative mutated transcription factor that c-Jun potentially in conjunction with other factors that interact with it is necessary for transformation by ras. The mutant Jun lacks an activation domain and blocks stimulation of transcription by several oncoproteins, including Ras, v-Src, polyoma middle T, c-Jun and c-Fos, as well as by the tumour promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). The inhibition is specific for motifs that bind Jun: activation of an NF-kappa B/Rel motif is not affected. This Jun mutant acts as an anti-oncogene in ras-transformed cells, generating non-transformed revertants that have acquired anchorage and density-dependent growth, as well as reduced tumorigenicity in vivo. Mutants of other transcription factors designed to inhibit transformation will enable us to study their role in signal transduction.

Animals↗
PubMed1991

Characterization of two Drosophila POU domain genes, related to oct-1 and oct-2, and the regulation of their expression patterns.

We have characterized two genes from Drosophila melanogaster that encode proteins with POU domains showing a high degree of identity with the human Oct-1 and Oct-2 transcription factors. These POU domain genes, pdm-1 and pdm-2, are expressed at high levels during early embryogenesis and at lower levels throughout the rest of development. Both genes are expressed as two stripes in the presumptive abdominal region during the blastoderm stage, followed by thirteen stripes in the germ band extended stage. This pattern of expression is altered in mutants for a gap gene (hunchback) and a pair-rule gene (fushi tarazu). In later stage embryos, both pdm-1 and pdm-2 are expressed in selected neuroblasts in the ventral nervous system, with higher levels in the three thoracic segments and lower levels in the abdominal segments. The low level of expression in the abdominal segments is maintained by the genes within the bithorax complex (BX-C). We have also identified the cells in the dorsal and lateral clusters of the peripheral nervous system that express pdm-1 and pdm-2, and show that some of these cells derive from lineages that require BX-C functions. Together, these results suggest that previously characterized members of the embryonic regulatory hierarchy specify the patterns of the POU domain gene expression, which, in turn, function during neurogenesis and perhaps in earlier stages.

Amino Acid Sequence↗
PubMed1991

Molecular definition of the morphogenetic and regulatory functions and the cis-regulatory elements of the Drosophila Abd-B homeotic gene.

The Abdominal-B (Abd-B) gene, a member of the Drosophila bithorax complex, is required during development to specify the identity of parasegments 10-14. Based on genetic studies, Casanova, J., Sánchez-Herrero, E. and Morata, G. (1986) Cell 47, 627-636, proposed that the Abd-B gene consists of two distinct elements that provide a morphogenetic (m) function in PS 10-13 and a regulatory (r) function in PS 14, where it represses m function. Here we present molecular confirmation of this genetic model. Using specific antibodies, we show that the 55 X 10(3) M(r) and 30 X 10(3) M(r) Abd-B proteins, predicted by cDNA analysis, are indeed present in PS 10-13 and PS 14, respectively. We also examine Abd-B mRNA and protein expression patterns in embryos mutant for either the m or r function. These data allow us to unambiguously assign m function to the 55 X 10(3) M(r) protein and r function to the 30 X 10(3) M(r) protein. Furthermore, as postulated by the model, transcription of the mRNA encoding the m protein is derepressed in PS 14 in the absence of r function. We have also studied the effect of mutations mapping in the infra-abdominal (iab) region located downstream of the Abd-B gene. Genetic studies suggest that the iab region contains cis-acting regulatory elements controlling Abd-B expression in PS 10-12. We present molecular evidence for the presence of downstream cis-regulatory elements by analyzing Abd-B mRNA and protein patterns in iab-6 and iab-7 embryos. Our analysis reveals the presence of parasegment and cell-specific regulatory elements of the Abd-B gene within each iab region. The Abd-B gene may provide a model for the understanding of similarly complex homeotic genes in higher organisms.

Animals↗
PubMed1990

Tropical arthritis in Papua New Guinea: a reactive arthritis.

An idiopathic, asymmetrical oligoarthritis affecting young adults is prevalent in the tropical regions of Africa, Asia and Melanesia. A serological study was undertaken in 23 consecutive patients with polyarthritis. Each patient was assigned two paired control subjects. A standardized history, physical examination and investigations were performed. Acute and convalescent sera were examined for evidence of recent infection. The presence of HLA-B27 was determined. Twelve (52%) of the 23 patients had more than one of the clinical features of a reactive arthritis. No serological evidence was found of acute infection with viruses (arboviruses, enteroviruses, mumps, rubella, adenoviruses, Epstein-Barr virus and hepatitis B), Chlamydia, Mycoplasma, Yersinia or syphilis. HLA-B27 was found in 14 (61%) of the 23 patients in contrast with in seven (17%) of the 41 control subjects (P less than 0.001). In two patients with HLA-B27, diagnostic titres of antibodies to Campylobacter jejuni-Campylobacter coli indicated recent infection. The presence of HLA-B27 antigen was significantly (P less than 0.05) associated with the presence of the clinical features of reactive arthritis. This study suggests that "tropical arthritis" commonly is a reactive arthritis that is associated with the presence of HLA-B27.

Acute Disease↗
PubMed1990

A double-blind, placebo-controlled trial of intravenous immunoglobulin therapy in patients with chronic fatigue syndrome.

PURPOSE: The chronic fatigue syndrome (CFS) is characterized by profound fatigue, neuropsychiatric dysfunction, and frequent abnormalities in cell-mediated immunity. No effective therapy is known. PATIENTS AND METHODS: Forty-nine patients (40 with abnormal cell-mediated immunity) participated in a randomized, double-blind, placebo-controlled trial to determine the effectiveness of high-dose intravenously administered immunoglobulin G. The patients received three intravenous infusions of a placebo solution or immunoglobulin at a dose of 2 g/kg/month. Assessment of the severity of symptoms and associated disability, both before and after treatment, was completed at detailed interviews by a physician and psychiatrist, who were unaware of the treatment status. In addition, any change in physical symptoms and functional capacity was recorded using visual analogue scales, while changes in psychologic morbidity were assessed using patient-rated indices of depression. Cell-mediated immunity was evaluated by T-cell subset analysis, delayed-type hypersensitivity skin testing, and lymphocyte transformation with phytohemagglutinin. RESULTS: At the interview conducted by the physician 3 months after the final infusion, 10 of 23 (43%) immunoglobulin recipients and three of the 26 (12%) placebo recipients were assessed as having responded with a substantial reduction in their symptoms and recommencement of work, leisure, and social activities. The patients designated as having responded had improvement in physical, psychologic, and immunologic measures (p less than 0.01 for each). CONCLUSION: Immunomodulatory treatment with immunoglobulin is effective in a significant number of patients with CFS, a finding that supports the concept that an immunologic disturbance may be important in the pathogenesis of this disorder.

Adolescent↗
PubMed1990

The psychiatric status of patients with the chronic fatigue syndrome.

The prevalence of psychiatric disorder in 48 patients with chronic fatigue syndrome (CFS) was determined. Twenty-two had had a major depressive (non-endogenous) episode during the course of their illness, while seven had a current major (non-endogenous) depression. The pre-morbid prevalence of major depression (12.5%) and of total psychiatric disorder (24.5%) was no higher than general community estimates. The pattern of psychiatric symptoms in the CFS patients was significantly different to that of 48 patients with non-endogenous depression, but was comparable with that observed in other medical disorders. Patients with CFS were not excessively hypochondriacal. We conclude that psychological disturbance is likely to be a consequence of, rather than an antecedent risk factor to the syndrome.

Adolescent↗
PubMed1990

Cardiac rehabilitation in the workplace. Current concepts and methodology.

Identification and modification of risk factors for cardiovascular disease can be carried out effectively in the workplace. Coronary artery disease is multifactorial. A cardiac exercise program conducted by the occupational health nurse should serve as a catalyst for modification of all coronary risk factors. Employers have begun to value and support worksite cardiac rehabilitation programs because of the benefits of health care cost avoidance, increased attendance and productivity at work, and improved employee relations. It is the responsibility of the occupational health nurse and other health care providers to see that this continues.

Cardiac Rehabilitation↗