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Biomedical subjects

M E Hodson

Publications and source records attributed to M E Hodson.

At least 19 recordsLinked to original sources

Use of bone meal amendments to immobilise Pb, Zn and Cd in soil: A leaching column study.

The aim of this study is to test the stabilisation of metals in contaminated soils via the formation of low-solubility metal phosphates. Bone apatite, in the form of commercially available bone meal, was tested as a phosphate source on a mine waste contaminated made-ground with high levels of Pb, Zn and Cd. Triplicate leaching columns were set up at bone meal to soil ratios of 1:25 and 1:10, in addition to unamended controls, and were run for 18 months. The columns were irrigated daily with a synthetic rain solution at pH of 2, 3, and 4.4. After 100 days, the leachate Pb, Zn and Cd concentrations of all amended columns were significantly reduced. For 1:10 treatments, release of these metals was suppressed throughout the trial. For 1:25 treatments, Zn and Cd concentrations in the leachates began to increase after 300 days. DTPA and water extractions showed that Pb and Cd were more strongly held in the amended soils. This study concludes that the complexity of soil processes and the small quantities of metals sequestered precluded determination of a metal immobilisation mechanism.

Adsorption↗

Dornase alfa in the treatment of cystic fibrosis in Europe: a report from the Epidemiologic Registry of Cystic Fibrosis.

Dornase alfa (Pulmozyme) treatment for patients with cystic fibrosis (CF) has been shown to improve pulmonary function and reduce exacerbations of infection in a number of placebo-controlled double-blind studies. Data in the Epidemiologic Registry of Cystic Fibrosis (ERCF) in November 1998 were used to assess the long-term effectiveness in routine clinical practice of dornase alfa in terms of pulmonary function and frequency of acute pulmonary exacerbations in CF. At that time, the ERCF contained data on 13,684 CF patients, with a mean observation period of 2.3 years. To be included in the analysis, patients had to have 2 years of data in the Registry in appropriate detail. Overall, untreated patients showed a decline in forced expiratory volume in 1 sec over a 2-year period of -2.3% predicted, but treated patients were stable, showing a change of 0.3% predicted, i.e., a treatment benefit of 2.5%. Compared to untreated patients, there were 25 fewer exacerbations per 100 treated patients per year. The analysis suggested that younger patients were likely to benefit more from treatment. The findings of randomized clinical trials were supported by the data collected in routine clinical practice.

Adolescent↗

Time-related changes in pulmonary function after conversion to tacrolimus in bronchiolitis obliterans syndrome.

BACKGROUND: Bronchiolitis obliterans syndrome (BOS) is a leading cause of morbidity and mortality after lung and heart-lung transplantation. Present treatment is directed at the augmentation of pharmacologic immunosuppression. METHODS: This study examines the effect of substituting cyclosporine with tacrolimus on the forced expiratory volume in 1 second (FEV(1)) and on the forced expiratory flow between 25% and 75% of vital capacity (FEF(25%-75%)) in 32 patients who developed BOS. The proportional rates of decline of FEV(1) and FEF(25%-75%) before and after treatment with tacrolimus were calculated. The actuarial survival of responders and non-responders to tacrolimus was compared. Pre-operative and post-operative factors were investigated to determine any difference between the 2 groups. RESULTS: There were significant reductions in the rates of decline of FEV(1) and FEF(25%-75%) when the rates in the 3 months before conversion to tacrolimus were compared with subsequent rates at 0 to 3 months, 3 to 6 months, 6 to 9 months and 9 to 12 months after conversion. The rates of decline of FEV(1) and FEF(25%-75%) in the 3 months before conversion were 0.11 liters/month and 0.13 liters/s per month, respectively. This compares with the rates of decline for FEV(1) and FEF(25%-75%) for the 3 months after conversion to tacrolimus of 0.04 liters/month (p = 0.023) and 0.04 liters/s per month (p = 0.022), respectively. The actuarial survival at 1 year from the time of conversion to tacrolimus for the responder sub-group and the non-responder sub-group were 89.2% and 75%, respectively, and at 4 years after conversion were 61.3% and 56.3%, respectively (p = 0.92). CONCLUSIONS: Tacrolimus rescue therapy is effective at stabilizing lung function in patients with BOS, and this effect is apparent up to 12 months after conversion from cyclosporine.

Bronchiolitis Obliterans↗

The psychosocial and psychiatric side of cystic fibrosis in adolescents and adults.

Increasing numbers of cystic fibrosis (CF) patients are surviving into adulthood. An understanding of the psychiatric and psychosocial aspects of CF in adults and adolescents is therefore more important than ever. There is a large body of evidence indicating that the psychological and psychosocial functioning of people with CF is similar to that of well people, until the disease becomes severe. However, there is also evidence that patients do suffer an increased likelihood of psychiatric problems, such as depression, and of scoring poorly on physical functioning measures of quality of life. Studies have found conflicting evidence as to any association between degree of respiratory impairment and psychological functioning. Coping styles seem to have a large effect upon the quality of life of CF patients. People with cystic fibrosis can have problems with sexuality, platonic relationships and independence. Families of patients also suffer problems, which can affect the patients themselves. Non-compliance is a complicated problem with many patients. New treatments for people with CF are emerging, such as lobe transplants from live donors and gene therapy, with possible new psychosocial problems resulting. Furthermore, older studies are becoming increasingly inapplicable as treatment and prognosis changes. Therefore, more research is needed in this field.

Activities of Daily Living↗

New clinical evidence from the European tobramycin trial in cystic fibrosis.

The major cause of morbidity and mortality in patients with cystic fibrosis (CF) is respiratory disease (Penketh et al., Thorax 1987; 42: 526-532). Recent studies in the USA have shown that intermittent administration of inhaled tobramycin is beneficial to patients with CF who are chronically infected with Pseudomonas aeruginosa (Ramsey et al., N Engl J Med 1999; 340: 23-30; Ramsey et al., Proceedings of the 12th Annual North American Cystic Fibrosis Conference, 1998, Montreal, Canada; Ramsey et al., Abstract from 23rd European Cystic Fibrosis Conference, 1999, the Hague, Netherlands). In Europe, the use of nebulised colistin in patients chronically infected with P. aeruginosa is widespread. A recently published study compared the efficacy and safety of tobramycin nebuliser solution (TNS) and nebulised colistin in CF patients . One hundred and fifteen patients were randomised to receive either TNS or colistin in a multi-centre open-labelled study that assessed change from baseline in FEV(1) and sputum P. aeruginosa density. TNS produced a mean 6.7% improvement in lung function (P=0.006), whilst there was no significant improvement in the colistin-treated patients. The TNS-treated patients had a significantly greater improvement in lung function than those treated with colistin (P=0.008). The safety profile of both treatments was good. We conclude that patients treated with TNS for 1 month experience improved lung function compared with patients treated with colistin.

Administration, Inhalation↗

Cystic fibrosis-related diabetes: the role of peripheral insulin resistance and beta-cell dysfunction.

AIMS: The goal of this study was to identify the glycaemic status and investigate the roles of peripheral insulin resistance (IR) and pancreatic -cell dysfunction in the pathogenesis of cystic fibrosis-related diabetes (CFRD) in adult cystic fibrosis (CF) patients with no previous history of glycaemic disturbances. METHODS: The glucose tolerance status of 68 CF patients was determined using 2-h oral glucose tolerance tests (OGTTs). Peripheral IR was measured using the homeostasis model assessment for insulin resistance (HOMA-IR) in the CF group and 46 normal healthy control subjects. Pancreatic -cell function, calculated as the ratio between the 30-min increment in plasma insulin and the corresponding 30-min post-OGTT plasma glucose concentration, was also measured in a subset of 30 CF patients and 16 normal healthy controls. Extended 180-min OGTTs, with frequent plasma glucose and insulin sampling, were also undertaken in 24 CF patients and eight normal healthy controls to determine glucose-induced insulin response. RESULTS: Of the 68 CF patients studied, 41, 18 and nine were found to have normal, impaired and diabetic glucose tolerances, respectively. The mean HOMA-IR values (mU/mmol) in the CF patients, as a whole, were not significantly different compared with the normal healthy controls (CF 2.2 +/- 1.1 vs. control 1.8 +/- 0.9; NS). Within the CF group, glycaemic status had no impact on HOMA-IR (mU/mmol): 2.2 +/- 1.2 (normal glucose tolerance); 2.0 +/- 1.0 (impaired glucose tolerance); and 2.3 +/- 1.1 (diabetic glucose tolerance). -cell function (mU/mmol) was not only significantly lower in the CF group (CF 1.65 +/- 1.8; P < 0.001) but also in the CF group with normal glucose tolerance (2.25 +/- 2.10; P < 0.01) compared with healthy control (4.98 +/- 2.38). Mean plasma glucose concentrations were generally higher and mean plasma insulin concentrations lower in the CF group as a whole when compared with normal healthy controls. Within the CF group, there was a progressive decline in glucose-induced insulin release with worsening glycaemic status. CONCLUSIONS: A lack of difference in peripheral IR, measured using HOMA-IR, in the CF group and healthy controls or within the CF group with differing glycaemic status suggests that IR does not have a significant role in the pathogenesis of CFRD. Pancreatic -cell function, already subnormal in CF patients with OGTT-defined normal glucose tolerance status, deteriorated further with worsening glycaemic status. This suggests that insulinopenia plays a prominent role in the pathogenesis of glucose intolerance and subsequent development of CFRD.

Adult↗

Noninvasive ventilation in cystic fibrosis patients with acute or chronic respiratory failure.

The experience of using noninvasive ventilation (NIV) in 113 adult cystic fibrosis (CF) patients with chronic respiratory failure, during episodes of acute deterioration in respiratory function is reported. The patients aged 15-44 yrs were divided into three groups. Group A consisted of 65 patients (median forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) 0.7/1.4 L) who were on a lung transplant waiting list. Group B consisted of 25 patients (median FEV1/FVC 0.7/1.4 L) who were being evaluated for lung transplantation. Group C consisted of 23 patients (median FEV1/FVC 0.6/1.2 L) who were not being considered for lung transplantation. The mean duration of NIV support for groups A, B and C was 61 (range: 1-600) days, 53 (1-279) days and 45 (0.5-379) days respectively. Twenty-three patients in group A subsequently received lung transplantation and 12 of these patients had a median survival of 39 months postsurgery. Thirty-nine patients died and three awaited transplantation. Five patients in group B received a transplant four of whom survived; thirteen patients died and seven awaited transplantation. Twenty patients in group C died. Noninvasive ventilation improved hypoxia but failed to correct hypercapnia in these cystic fibrosis patients. Noninvasive ventilation is useful in the treatment of acute episodes of respiratory failure in cystic fibrosis patients with end-stage lung disease who have been accepted, or are being evaluated, for lung transplantation. For these patients, there is a possibility of prolonging life if they are successfully treated for their acute episode of respiratory failure until transplantation. In this group, treatment is not merely prolonging the process of dying.

Acute Disease↗

A randomised clinical trial of nebulised tobramycin or colistin in cystic fibrosis.

Chronic infection with Pseudomonas aeruginosa is associated with progressive deterioration in lung function in cystic fibrosis (CF) patients. The purpose of this trial was to assess the efficacy and safety of tobramycin nebuliser solution (TNS) and nebulised colistin in CF patients chronically infected with P. aeruginosa. One-hundred and fifteen patients, aged > or = 6 yrs, were randomised to receive either TNS or colistin, twice daily for 4 weeks. The primary end point was an evaluation of the relative change in lung function from baseline, as measured by forced expiratory volume in one second % predicted. Secondary end points included changes in sputum P. aeruginosa density, tobramycin/colistin minimum inhibitory concentrations and safety assessments. TNS produced a mean 6.7% improvement in lung function (p=0.006), whilst there was no significant improvement in the colistin-treated patients (mean change 0.37%). Both nebulised antibiotic regimens produced a significant decrease in the sputum P. aeruginosa density, and there was no development of highly resistant strains over the course of the study. The safety profile for both nebulised antibiotics was good. Tobramycin nebuliser solution significantly improved lung function of patients with cystic fibrosis chronically infected with Pseudomonas aeruginosa, but colistin did not, in this study of 1-month's duration. Both treatments reduced the bacterial load.

Administration, Inhalation↗

Sulphation of the salivary mucin MG1 (MUC-5B) is not correlated to the degree of its sialylation and is unaffected by cystic fibrosis.

Defective acidification of intracellular organelles, particularly the trans-Golgi network, has been proposed to explain the decreased sialylation and increased sulphation of secreted proteins in cystic fibrosis (CF). To test this hypothesis we compared expression of sulphate and sialic acid on three salivary mucins namely MG1 (MUC-5B), MG2 (MUC-7) and GL. Proteins in whole mouth saliva (WMS) from four individuals were separated by fast protein liquid chromatography (FPLC) on a Superdex 200 column and the partially purified mucins slot-blotted and assayed for sulphate content by staining with Alcian Blue. Sulphation varied with the individual and with the mucin: MG1 was the most sulphated and contributed almost the entire sulphate content of WMS. These results allowed us to test small volumes of WMS from 20 CF patients and age- and sex-matched controls for estimates of sulphate content on MG1. Wherever possible sulphate on MG1 was also visualised by staining washed SDS-PAGE gels with Alcian Blue at pH 1.0. To assess the sialic acid content of salivary mucins, electroblots of SDS-PAGE gels were probed with labelled Triticum vulgaris agglutinin. In summary, our results show MG1 to be the main sulphated protein in whole mouth saliva and there are large differences in the expression of sulphate and of sialic acid on this mucin, both in control and CF groups. CF led neither a decrease in sialylation nor an increase in sulphation and direct comparisons of sialic acid content with sulphate in MG1 failed to reveal any obvious link between the two in health or in disease. Our data thus do not support the hypothesis of defective acidification as the underlying cause of altered glycosylation in CF, but point instead to inter-individual differences in expression/functioning of terminal glycosyltransferases for published observations. We thank the European Union Biomed II programme for support.

Acids↗

Altered sialyl- and fucosyl-linkage on mucins in cystic fibrosis patients promotes formation of the sialyl-Lewis X determinant on salivary MUC-5B and MUC-7.

Destruction of the lungs as a consequence of recurrent infections with microorganisms such as Pseudomonas aeruginosa remains the underlying cause of most morbidity and mortality in cystic fibrosis (CF). We have hypothesized that changes in the glycosylation of key tracheal mucins such as MUC5B and MUC7 might increase the risk of pulmonary disease in CF patients. However, in preference to sputum we have examined the sugar-chains on these mucins in saliva because in the latter not only can the glycoproteins be collected from controls, but they are essentially free from modifications made following bacterial infection in disease. Proteins in ductal or whole-mouth saliva from 20 CF patients with the Delta F-508 CFTR mutation and age-and sex-matched controls were separated by SDS-PAGE and blotted onto nitrocellulose and then probed with labelled lectins of known specificity. Linkage of terminal sialic acid on the blotted mucins was determined using Sambucus nigra agglutinin (detects the 2-->6 linkage) and Maackia amurensis agglutinin (the 2-->3 linkage). Fucose was detected by Ulex europaeus agglutinin-1 (1-->2 linkage) and Aleuria aurantia agglutinin (1-->3 linkage). We found that each mucin shows a characteristic glycosylation pattern and in controls most of the sialic acid is 2-->6 linked on MG1 (MUC 5B) and 2-->3 linked on MG2 (MUC 7). CF is associated with a shift from a 2-->6 linkage to a 2-->3 linkage on MG1 with some patients showing almost no 2-->6 linkage; 2-->3 linkage on MG2 is similarly increased in disease in some individuals. The expression of fucose on these mucins is also raised in CF patients. These shift to a 2-->3 linkage of sialic acid, and with increased fucosylation this promotes the formation of sialyl-Lewis X antigen detected on CF mucins in our study. These changes will be tested for their correlation with the severity of lung disease. We gratefully acknowledge support from the European Union Biomed-II Programme.

Cystic Fibrosis↗

Presence of cystic fibrosis-related diabetes mellitus is tightly linked to poor lung function in patients with cystic fibrosis: data from the European Epidemiologic Registry of Cystic Fibrosis.

Data derived from a cross-sectional analysis of 7,566 patients stratified into six age groups were used to compare lung function, body mass index (BMI), and weight for age in patients with and without cystic fibrosis-related diabetes mellitus (CFDM). The presence of CFDM was tightly linked to poor lung function, regardless of age. The mean value of FEV(1) % predicted in the age groups < 10, 10-< 15, 15-< 20, 20-< 25, 25-< 30, and 30 years or older were 87%, 77%, 69%, 58%, 55%, and 53% in the nondiabetic cystic fibrosis (CF) patients as compared to 79%, 66%, 55%, 49%, 46%, and 44% in the diabetic CF patients. BMI and weight for age were also lower in diabetic than nondiabetic CF patients in all age groups, except for BMI in the youngest patients. The difference in lung function and in nutritional parameters between diabetic and nondiabetic CF patients was not linked to presence or absence of any specific pathogen in the lower respiratory tract. These results confirm and extend those of earlier studies in smaller numbers of patients, and they clearly identify CFDM as a powerful determinant of severe lung disease and reduced survival in patients with CF and diabetes mellitus.

Adolescent↗

Vertebral deformities and low bone mineral density in adults with cystic fibrosis: a cross-sectional study.

Patients with cystic fibrosis (CF) have low bone mineral density (BMD). The clinical relevance of this is not clearly established. The aim of this study was to determine the prevalence of low BMD and vertebral deformities in CF adults with varied disease severity. One hundred and seven patients (58 men) aged 18-60 years underwent dual-energy X-ray absorptiometry scanning of the lumbar spine and hip, radiology of the spine and biochemical studies. Thirty-eight percent had a Z-score of < -1, with 13% having Z-scores < -2. Seventeen percent had evidence of vertebral deformity on radiography, mostly in the thoracic spine. Thirty-five percent reported past fractures, of which 9% were rib fractures. Percent predicted forced expiratory volume in 1 second (FEV1) and the amount of daily physical activity were positively related to BMD. The number of intravenous antibiotic courses in the previous 5 years was negatively related to BMD. Patients with a history of rib fracture and CF-related diabetes had significantly lower femoral neck BMD (p < 0.02). The median serum 25-hydroxyvitamin D was 28 nmol/l, with 36% of patients having levels below 25 nmol/l despite vitamin D supplementation. Forty-four percent had raised levels of urinary pyridinium crosslinks (NTx). In conclusion, fragility fractures and hypovitaminosis D occur commonly in adult patients with CF. Low BMD occurs in patients with more severe disease and significantly relates to FEV1, infective exacerbations and daily energy expended in physical activity.

Absorptiometry, Photon↗

Effect of bone meal (calcium phosphate) amendments on metal release from contaminated soils--a leaching column study.

Metal-contaminated soil may be remediated in situ by the formation of highly insoluble metal phosphates if an appropriate phosphorus (P) source can be found. Leaching column experiments have been carried out to assess the suitability of bone meal as such a source. Bone meal additions reduced metal release from a contaminated soil, increased soil and leachate pH and decreased soil leachate toxicity. Minimal P leaching occurred from the soil. The data are consistent with a proton consuming bone meal (calcium phosphate) dissolution reaction followed by the formation of metal phosphates. Although, no metal phosphates were observed to form using X-ray diffraction of scanning electron microscopy this could be due to their low concentration. Relatively low (1:50 bone meal:soil) concentrations of fine (90-500 microns) bone meal would appear to be an effective treatment for metal-contaminated soils.

Biological Products↗

Changes in the leachability of metals from dredged canal sediments during drying and oxidation.

The behaviour of metals in canal sediments after their disposal to land has important implications for the environmental management of canal dredgings. The leaching behaviour of trace metals was investigated in a laboratory-based experiment using sediment from a canal in the UK (139 mg Zn kg-1dry sediment, 1.1 mg Cd, kg-1dry sediment 31.5 mg Cr kg-1dry sediment, 20.6 mg Cu kg-1dry sediment 48.4 mg Ni kg-1dry sediment, 43.4 mg Pb kg-1dry sediment and 7.6 mg As kg-1dry sediment). The sediment was allowed to dry. Cores (10 cm long) of the drying canal sediment were taken over a period of 12 weeks. A simple water extraction procedure was used to investigate changes in metal leachability at varying depths through the cores. Metal leachability increased over the first five weeks of drying and then subsequently decreased between weeks five and twelve, (e.g. Cd increased from approximately 0.006 to 0.018 mg/kgsediment then decreased to approximately 0.006 mg/kgsediment, Zn increased from approximately 1.5 to 3 mg/kgsediment and then decreased to approximately 1.5 mg/kgsediment). These results were combined with sulphide/sulphate ratios, which showed a decrease as the sediment dried (e.g. at 2-4 cm depth from approximately 1 to 0.49), and BCR sequential extraction data. Most metals (except Cd and As) showed a redistribution from the residual phase into more mobile phases as the sediment dried and oxidised. Metal leachability was strongly correlated with the sulphide/sulphate ratio with leachability normally increasing with decreasing sulphide/sulphate ratio. The combined results were used to infer the likely behaviour of dredged material upon disposal to land.

Environmental Monitoring↗

Wasting as an independent predictor of mortality in patients with cystic fibrosis.

BACKGROUND: Cystic fibrosis (CF) is the most common life threatening autosomal recessive disorder in the white population. Wasting has long been recognised as a poor prognostic marker in CF. Whether it predicts survival independently of lung function and arterial blood gas tensions has not previously been reported. METHODS: 584 patients with CF (261 women) of mean (SD) age 21 (7) years were studied between 1985 and 1996, all of whom were being followed up in a tertiary referral centre. Lung function tests, body weight, arterial blood oxygen (PaO(2)) and carbon dioxide (PaCO(2)) tensions were measured. The weight was calculated as a percentage of the ideal body weight for age, height, and sex. RESULTS: Forced expiratory volume in one second (FEV(1)) recorded at the start of the study was 1.8 (1.0) l (52 (26)% predicted FEV(1)), PaO(2) 9.8 (1.9) kPa, PaCO(2) 5.0 (0.9) kPa, and % ideal weight 92 (18)%. During the follow up period (45 (27) months) 137 patients died (5 year survival 72%, 95% CI 67 to 73). FEV(1), % predicted FEV(1), PaO(2), % ideal weight (all p<0.0001), and PaCO(2) (p=0.04) predicted survival. In multivariate analysis, % predicted FEV(1) (p<0.0001), % ideal weight (p=0.004), and PaCO(2) (p=0.02) were independent predictors of outcome. Patients with >85% ideal body weight had a better prognosis at 5 years (cumulative survival 84%, 95% CI 79 to 89) than those with < or =85% ideal weight (survival 53%, 95% CI 45 to 62), p<0.0001. Percentage predicted FEV(1) (area under curve 0.83; 95% CI 0.78 to 0.87) and % ideal weight (area under curve 0.74; 95% CI 0.68 to 0.79) were accurate predictors of survival at 5 years follow up (receiver-operating characteristic analysis). CONCLUSIONS: Body wasting is a significant predictor of survival in patients with CF independent of lung function, arterial blood oxygen and carbon dioxide tensions.

Adolescent↗

A case-controlled study with dornase alfa to evaluate impact on disease progression over a 4-year period.

BACKGROUND: Chronic endobronchial sepsis and profuse airway secretions dominate pulmonary disease in cystic fibrosis. Recombinant human DNase I (dornase alfa) reduces the viscoelasticity of airway secretions and hence may improve clearance of airway secretions. OBJECTIVES: To evaluate the long-term influence of dornase alfa on disease progression by performing a case-controlled study with dornase alfa over a period of 4 years. METHODS: A cohort of patients with cystic fibrosis who have been treated with dornase alfa were matched with a control group of patients with cystic fibrosis who had not received treatment with dornase alfa. The patients were matched by pulmonary function, age, and then sex. All available measurements of forced expiratory volume in one second (FEV1), height, weight and sputum bacteriology were collected for periods when the patients were free from respiratory exacerbations. RESULTS: Thirty-eight patients were matched. Slopes of median changes in FEV1 were -2.19 (-3.32, -1.06) in the control group and -0.75 (-1.87, 0.36) in the dornase alfa-treated group (p = 0.076). There were more infective exacerbations per patient year in the control group [3.13 (1.25-4.25)] in comparison to the dornase alfa group [1.25 (0.63-3.0), p = 0.035] over the 4-year treatment period. Antibiotic requirements were also greater with a median 43.75 (17.5-60.0) days of intravenous antibiotic use per patient year in the control group and 16.25 (8.5-44.0) days in the dornase alfa group (p = 0.034). CONCLUSIONS: The trends suggest that dornase alfa may have some influence on disease progression but in view of the limitations of the current study the need for further long-term studies in larger cohorts of patients is emphasised.

Adult↗