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Biomedical subjects

C Mawdsley

Publications and source records attributed to C Mawdsley.

At least 19 recordsLinked to original sources

Operator exposure when applying amenity herbicides by all-terrain vehicles and controlled droplet applicators.

A total of 33 surveys of amenity herbicides took place during 1998-1999. These surveys concentrated on two application methods: all-terrain vehicles (ATVs) and controlled droplet applicators (CDAs). The purpose of these surveys was to measure surface deposition and potential inhalation exposure of the operators to the spray fluid used. This paper recommends that the following indicative values should inform risk assessments for these types of application. ATV: The potential dermal exposure (PDE) to spray fluid (21 sample sets) ranged between 0.7 and 6.8 ml/h of spray fluid, median 2.0 ml/h based on patch samplers. Exposure to the hands, as collected on cotton gloves, ranged between 0.6 and 13.6 ml/h, median 3.0 ml/h. Potential exposure to spray fluid by inhalation was found in 85% of the samples, range 7-37 mg/m(3), median of non-zero values at 16 mg/m(3). CDA: The PDE to spray fluid (12 sample sets) ranged between 0.003 and 0.826 ml/h of fluid, median 0.133 ml/h, based on patch samplers. Exposure to the hands, as collected on cotton gloves inside protective gloves, ranged up to 0.06 ml/h, median 0.004 ml/h, and on socks ranged up to 0.05 ml/h, median 0.001 ml/h. Potential exposure by inhalation was low: detected in just 33% of the samples, range 0.02-0.61 mg/m(3), median 0.12 mg/m(3).

Air Pollutants, Occupational↗

Withdrawal of life support: how the family feels, and why.

The objectives of this study were to develop an instrument to assess the satisfaction of family members with withdrawal of life support (WLS), and to determine which factors are associated with greater levels of satisfaction. To do this, we developed a self-administered questionnaire that was sent to the next-of-kin of intensive care unit (ICU) patients dying following WLS. Over a six-month period, 69 patients died following WLS in the ICU. Three letters were returned "address unknown", 33 did not respond, and 33 responded, of whom 29 agreed to participate (29/66 = 44% of those contacted). Of these, 24 (83%) strongly agreed with the patient's death being compassionate and dignified, one moderately agreed, one mildly agreed, one was neutral and two strongly disagreed. Items associated with greater satisfaction included: the process of WLS being well explained, WLS proceeding as expected, patient appearing comfortable, family/friends prepared for the decision, appropriate person initiating discussion, adequate privacy during WLS, chance to voice concerns. The study suggests factors that are important to consider in ensuring family comfort with the process of withdrawing life support.

Analysis of Variance↗

Differential regulation of glucocorticoid receptor expression by ligand in fetal rat lung cells.

The glucocorticoid receptor (GR) mediates glucocorticoid stimulation of surfactant production by fetal mammalian lung. In many other tissues, glucorticoids decrease expression of GR, thereby reducing responsiveness to these hormones. We therefore determined whether there is a similar effect of exogenous glucocorticoids on GR in fetal rat whole lung, and in the principal cell types involved in the stimulation of surfactant, the fibroblasts and the epithelial cells. The ontogeny of GR in late gestation lung differed between the two cell types, with maximal levels occurring in fibroblasts on gestational d 19, and on d 20 in epithelial cells. Administration of dexamethasone (1 mg/kg) to the mother on gestational d 18 or 19 (term = 22 d) increased specific GR binding activity in whole lung 24 h later. Furthermore, in vitro, incubation of cultured fibroblasts of gestational d 20 with 10(-7) M cortisol increased GR immunoreactive protein and binding activity in a dose- and time-dependent manner, without affecting cellular levels of GR mRNA. However, identical treatment of d 20 distal airway epithelial cells was followed by decreased GR protein without significant change in cellular GR mRNA. Surfactant protein-A protein levels, taken as assessments of lung maturation, were increased in response to the same treatment. Our findings suggest that hormonal regulation of GR in fetal lung cells occurs at a posttranscriptional level, and is cell-specific. In the context of substantial increases in circulating glucocorticoid concentrations during late gestation, these findings may be of physiologic importance to the biochemical maturation of the antenatal lung.

Animals↗

Platelet-derived growth factors and growth-related genes in rat lung. III. Immunolocalization during fetal development.

To further study the role of platelet-derived growth factor (PDGF) in fetal lung development, the distribution of the PDGF homodimers PDGF-AA and PDGF-BB was examined by immunohistochemistry in embryonic and fetal rat lung from d 12 to 22 of gestation (term = 22 d). PDGF-AA and PDGF-BB were localized to airway epithelial cells as early as d 12 of gestation, 2 d before their appearance in mesenchymal cells. Both PDGF homodimer immunoreactivities increased until the late pseudoglandular stage of lung development, followed by fluctuations in reactivity during the canalicular stage. Only weak immunoreactivity to either PDGF homodimer was evident during the saccular stage of lung development. Immunodetection by Western blotting revealed that PDGF-AA and PDGF-BB homodimer protein concentrations were high during the embryonic and pseudoglandular stage of lung development and decreased with advancing gestation. We conclude that the presence of PDGF in both developing airway epithelial cells and mesenchymal cells, as well as gestation-dependent changes of PDGF homodimers, is compatible with a role for this growth factor during fetal lung development.

Animals↗

Chronic idiopathic polyneuropathy treated with azathioprine.

The results of azathioprine therapy in five patients with chronic progressive or relapsing idiopathic inflammatory polyneuropathy are described. In four patients a sustained improvement followed treatment and in the other patient azathioprine successfully replaced corticosteroid therapy. The improvement was often delayed for up to three months. The literature on the use of azathioprine in chronic polyneuropathy is reviewed. We suggest that there is a place for azathioprine treatment in patients with chronic idiopathic polyneuropathy resistant or intolerant to corticosteroid treatment.

Adolescent↗

Parkinson's disease: long-term results of levodopa therapy.

The long-term results of levodopa therapy in Parkinsonian patients is described. Between January 1969 and December 1972, dopaminergic therapy was started in 186 patients with Parkinson's disease. Their progress after six months, five years and in the autumn of 1980, was assessed. The initial benefit in the majority of patients was followed by a gradual loss of efficacy in most patients with increasing side effects of central-mediated type. We suggest that it may be wise to delay the onset of levodopa therapy until progress of the disease makes treatment imperative.

Adult↗

A study of the incidence of epilepsy following ECT.

In a group of 166 patients who had received electroconvulsive therapy more than one year previously the prevalence of epilepsy did not differ significantly from that found in the community as a whole. The findings suggest that a kindling process is not a clinical hazard following repeated electrically induced seizures.

Adult↗

CSF studies on the relationship between dopamine and 5-hydroxytryptamine in Parkinsonism and other movement disorders.

In Parkinson's disease, the concentration of homovanillic acid (HVA) was reduced in lumbar CSF from patients with idiopathic Parkinsonism (n = 54, P less than 0.05) and post-encephalitic Parkinsonism (n = 19, P less than 0.01). The reduction in the concentrations of 5-hydroxyindolylacetic acid (5-HIAA) was not significant, and there was no alteration in the levels of 4-hydroxy-3-methoxyphenylethylene glycol (MHPG). Treatment with L-dopa increased the concentration of HVA in the CSF (P less than 0.05) but had no effect on the levels of 5-HIAA and MHPG. Carbidopa given in combinations with L-dopa produced similar CSF concentrations of dopa as did L-dopa alone but caused less than half the rise in HVA. Fourteen patients who became functionally independent on treatment with L-dopa had higher 5-HIAA levels than 23 patients who showed no such improvement (P less than 0.001), suggesting that intact 5-hydroxyltryptamine neurones may be important in the therapeutic response to L-dopa. In a variety of movement disorders, the levels of HVA, 5-HIAA, and MHPG were not significantly different from age-matched controls. Treatment with tetrabenazine did not significantly alter the metabolite levels in patients in whom it produced either improvement, or side effects.

Aged↗

Monoamine metabolites in cerebrospinal fluid in multiple sclerosis.

The concentrations of homovanillic acid (HVA), 5-hydroxyindolylacetic acid (5-HIAA), and 4-hydroxy, 3-methoxyphenylethylene glycol (MHPG) were estimated in the lumbar cerebrospinal fluid (CSF) of control subjects and in some patients who probably, and others who definitely, suffered from multiple sclerosis (MS). In the control group, the concentration of HVA was lower in people who underwent lumbar puncture having fasted and been recumbent for 12 hours before the procedure than in those from whom CSF was obtained under non-standardised conditions. These studies demonstrate that a standardised procedure for lumbar puncture is required in order to obtain meaningful results. In patients suffering from MS the CSF 5-HIAA concentrations were significantly lower than in comparable controls but the HVA concentrations did not differ. There was no relationship between metabolite concentrations, site of lesion, the duration of the disease, gamma-globulin levels nor the occurrence of relapse within the previous month.

Female↗

Neuropathy associated with hepatitis in patients maintained on haemodialysis.

During a study of peripheral nerve function in chronic renal failure, 11 patients who were being treated by chronic intermittent haemodialysis developed serum hepatitis. Before the infection there was a trend towards improvement in nerve conduction velocities. A pronounced deterioration in the conduction velocities in motor fibres of peripheral nerves occurred in association with hepatitis. In the months after recovery from the infection there was again a trend towards improvement in conduction velocities. We suggest that this reflects the occurrence of a peripheral neuropathy which is at least in part demyelinating. The neuropathy is related to the serum hepatitis, but its pathogenesis is indeterminate.

Chronic Disease↗

Treatment of Parkinsonism with Laevo-dopa.

Thirty-two patients with Parkinsonism were treated with L-dopa. Nine were markedly and 14 moderately improved. Twenty patients tolerated the drug well, derived definite improvement, and were treated for an average period of six months. Improvement was sustained during this period even though the average daily dosage of L-dopa was reduced. Dose-dependent side-effects occurred in 25 patients. It is suggested that dosage schedules should be flexible and tailored to the needs of each individual patient, and that treatment should be continued for six months before presuming it to be ineffective.It is concluded that L-dopa often ameliorates Parkinsonism for long periods, but its effect on the natural history of the disease is undertermined.

Adult↗