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Biomedical subjects

A Lloyd

Publications and source records attributed to A Lloyd.

At least 127 records · Page 7Linked to original sources
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↗
PubMed1989

Neurological disorders in AIDS: a study of 18 cases.

Neurological disorders were studied in 18 patients diagnosed to have AIDS and their findings are analysed. Amongst the problems seen were toxoplasmosis (9), cryptococcal meningitis (5), tuberculous meningitis (1), AIDS dementia complex (3), peripheral neuropathy (2), vertebrobasilar stroke, and a possible AIDS myelopathy in one case each. Their findings are discussed, and literature on the neurological disorders in AIDS reviewed.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Phosphorylation of bovine adrenal chromaffin cell tyrosine hydroxylase. Temporal correlation of acetylcholine's effect on site phosphorylation, enzyme activation, and catecholamine synthesis.

Tryptic peptide fragments of tyrosine hydroxylase isolated from 32PO4-prelabeled bovine adrenal chromaffin cells are resolved into seven phosphopeptides by reverse phase-high performance liquid chromatography. All seven of the peptides are phosphorylated on serine residues. Three of these putative phosphorylation sites, peptides 3, 5, and 6, are rapidly phosphorylated (5-fold in 15 s) by both acetylcholine stimulation and potassium depolarization of the cells, and this phosphorylation is accompanied by a similarly rapid activation of the enzyme. Both phosphorylation and activation are transient and do not account for the prolonged increase in catecholamine biosynthesis produced by these stimuli. Peptides 4 and 7 show a much slower and sustained increase in phosphorylation (3-fold in 4 min) in response to acetylcholine and potassium. Phosphorylation of these peptides correlates with the sustained increase in catecholamine biosynthesis rather than enzyme activation. Peptides 1 and 2 are not stimulated by any agonist yet employed and thus show no relation to enzyme activation or catecholamine biosynthesis. Phosphorylation of all five peptides by acetylcholine or potassium is calcium-dependent. In contrast to the stimulation of phosphorylation of tyrosine hydroxylase on multiple sites, forskolin stimulates the phosphorylation of only peptide 6, and this is accompanied by a coordinated activation of tyrosine hydroxylase and increased catecholamine biosynthesis. These findings show that the phosphorylation of tyrosine hydroxylase in intact cells is more complex than predicted from in vitro results, that at least two protein kinases are involved in the secretagogue-induced phosphorylation of tyrosine hydroxylase, and that the regulation of catecholamine biosynthesis, in response to phosphorylation, appears to involve both tyrosine hydroxylase activation and other mechanisms.

Acetylcholine↗