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Biomedical subjects

D Geddes

Publications and source records attributed to D Geddes.

At least 19 recordsLinked to original sources
PubMed2006

Effect and duration of lung volume reduction surgery: mid-term results of the Brompton trial.

UNLABELLED: Although many studies have reported improvement in lung function following LVRS, the magnitude of improvement and subsequent decline has not been evaluated against medical therapy after the second year. METHODS: Existing pulmonary function records were collapsed for ech participant since randomisation from Brompton LVRS trial cohort. Longitudinal data analysis was used to profile th history of medically treated patients and the effect of LVRS. RESULTS: Pulmonary function results were collated from survivors over a median of 25 (17 to 39) months. The estimated immediate increase in mean FEV1, following surgery was +0.2591 (0.179, 0.339), with a rate of change of -0.0051 (-0.009, -0.001) per month compared to medical therapy (p < 0.001). The changes in the secondary outcome measures (LVRS compared to medical therapy) were an increase in FVC (p = 0.004), decrease in RV (p < 0.001) and TLC (p < 0.001), with differences that were maintained over time. The initial reduction in RV/TLC ration was sustained (p < 0.001), but the estimated initial increase in peak flow was accompanied by a gradual decline that was not statistically significant (p = 0.062). KCOc showed no immediate change, but there was a gradual sustained increase with time (p = 0.009). Mean oxygen saturations improved and continued to do so compared to patients on medical therapy (p = 0.001). CONCLUSIONS: The immediate increase in FEV1 is not sustained, although the mechanical improvements of LVRS on increasing FVC, reducing both the RV and RV/TLC ratio, appear to be maintained. The important benefits of LVRS may be the gradual and sustained increase in transfer factor accompanied by improved oxygen saturations.

Female↗
PubMed2005

Improving rate of decline of FEV1 in young adults with cystic fibrosis.

BACKGROUND: CF is characterised by a progressive decline in lung function; reductions in this decline are often used as a measure of success in clinical trials. With improvements in treatment it may be that there has been a temporal shift in the pattern of the disease. METHODS: 318 patients born in five successive cohorts and attending a specialist clinic with at least two routine measurements of lung function made between the ages of 18 and 22 were included. The declines in their lung function were estimated and compared. RESULTS: The mean (SE) slopes for percentage predicted forced expiratory volume in 1 second (FEV(1)) and forced vital capacity (FVC) were -1.53 (0.36)% and -1.27 (0.34)%, respectively (NS). The annual deterioration in FEV(1) was -2.49%, -1.99% -2.20%, -1.65%, and -0.65% from the earliest to the most recent birth cohort; a similar pattern was observed for changes in FVC. There were no differences between male and female patients. Patients infected with Pseudomonas had a greater average decline in FEV(1) (-1.6% v -1.1%). CONCLUSIONS: The rates of decline in lung function in young adults with CF have diminished with successive birth cohorts. This has important implications for the design of clinical studies in this disease.

Adolescent↗
PubMed2004

Gene therapy progress and prospects: bringing gene therapy into medical practice: the evolution of international ethics and the regulatory environment.

The concept and application of ethical principles in the context of medical research is changing rapidly. This is especially true for fast moving fields such as gene therapy, a relatively new but rapidly maturing field offering opportunities to influence health at a fundamental level, which may become a cornerstone of medicine. By 2004, over 700 gene therapy clinical protocols had been initiated worldwide, and two highly publicized gene therapy-related side effects have helped to shape recent ethical debate. These events have influenced not only clinical trial design but also public opinion and systems of independent oversight. Both the science of gene therapy and the regulatory environment are continually evolving. How well the field is able to respond to these challenges will determine the extent to which gene therapy will ultimately be integrated into medical practice.

Animals↗
PubMed2004

Normal nasal mucociliary clearance in CF children: evidence against a CFTR-related defect.

Studies on mucociliary clearance (MCC) in cystic fibrosis (CF) have produced conflicting results. This study aimed to differentiate primary (ion transport-related) from secondary (inflammatory) causes of delayed MCC in CF. Nasal MCC was measured in 50 children (CF, primary ciliary dyskinesia (PCD) and no respiratory disease). Nasal lavage fluid was analysed for interleukin (IL)-8 and tumour necrosis factor-alpha. Similar measurements were obtained in adult CF patients with and without chronic sinusitis (CS). Children with CF had neither delayed MCC nor increased levels of cytokines. Conversely, children with PCD had prolonged MCC times (all >30 min) and significantly raised levels of IL-8. CS-positive CF adults had significantly slower MCC than CS-negative subjects, but IL-8 levels were low and similar in both groups. Decreased airway surface liquid and delayed mucociliary clearance are the postulated primary mechanisms in cystic fibrosis. However, the current study reports that cystic fibrosis children have normal nasal mucociliary clearance. Abnormalities appeared in cystic fibrosis adults with symptoms of chronic sinus disease, suggesting a secondary rather than primary phenomenon. Studies to explore this mechanism in the distal, more sparsely-ciliated airways could aid an understanding of pathogenesis and the development of new treatments.

Adolescent↗
PubMed2001

Management of influenza in patients with asthma or chronic obstructive pulmonary disease.

OBJECTIVE: To review the prevention and treatment of influenza in patients with asthma and/or chronic obstructive pulmonary disease (COPD). DATA SOURCES: Computer-assisted MEDLINE searches for article and manual searches of conference proceedings on influenza, influenza vaccination, rimantadine, amantadine, oseltamivir, zanamivir, asthma, and/or COPD. STUDY SELECTION: Published articles and pertinent conference abstracts in the areas mentioned in Data sources were selected. Articles included for review were studies conducted on humans. RESULTS: Annual vaccination against influenza is the currently accepted practice for influenza management in patients with asthma and/or COPD. However, despite the availability and use of vaccination, influenza continues to cause serious morbidity and increased mortality. The management of influenza in at-risk patients with the older antivirals such as amantadine or rimantadine has not been widely accepted because of the rapid emergence of resistant variants, their lack of effect against influenza B, and poor adverse event profile. A new class of influenza antivirals, the neuraminidase inhibitors, has recently become available for the management of influenza. The currently marketed neuraminidase inhibitors are zanamivir and oseltamivir. Clinical studies have shown that these neuraminidase inhibitors are effective for the treatment and chemoprophylaxis of influenza A and B. CONCLUSIONS: Vaccination against influenza remains the gold standard for the prevention of influenza in patients with asthma and/or COPD. The neuraminidase inhibitors zanamivir and oseltamivir are useful adjuncts to influenza vaccines for the management of influenza in these patients who are at high-risk of developing influenza related complications.

Antiviral Agents↗
PubMed2000

Effect of lung-volume-reduction surgery in patients with severe emphysema.

BACKGROUND: Although many patients with severe emphysema have undergone lung-volume-reduction surgery, the benefits are uncertain. We conducted a randomized, controlled trial of the surgery in patients with emphysema. Patients with isolated bullae were excluded because such patients are known to improve after bullectomy. METHODS: Potentially eligible patients were given intensive medical treatment and completed a smoking-cessation program and a six-week outpatient rehabilitation program before random assignment to surgery or continued medical treatment. After 15 patients had been randomized, the entry criteria were modified to exclude patients with a carbon monoxide gas-transfer value less than 30 percent of the predicted value or a shuttle-walking distance of less than 150 m, because of the deaths of 5 such patients (3 treated surgically and 2 treated medically). RESULTS: Of the 174 subjects who were initially assessed, 24 were randomly assigned to continued medical treatment and 24 to surgery. At base line in both groups, the median forced expiratory volume in one second (FEV1) was 0.75 liter, and the median shuttle-walking distance was 215 m. Five patients in the surgical group (21 percent) and three patients in the medical group (12 percent) died (P=0.43). After six months, the median FEV1 had increased by 70 ml in the surgical group and decreased by 80 ml in the medical group (P=0.02). The median shuttle-walking distance increased by 50 m in the surgical group and decreased by 20 m in the medical group (P=0.02). There were similar changes on a quality-of-life scale and similar changes at 12 months of follow-up. Five of the 19 surviving patients in the surgical group had no benefit from the treatment. CONCLUSIONS: In selected patients with severe emphysema, lung-volume-reduction surgery can improve FEV1, walking distance, and quality of life. Whether it reduces mortality is uncertain.

Adrenergic beta-Agonists↗
PubMed2000

Pretreatment with cationic lipid-mediated transfer of the Na+K+-ATPase pump in a mouse model in vivo augments resolution of high permeability pulmonary oedema.

Resolution of pulmonary oedema is mediated by active absorption of liquid across the alveolar epithelium. A key component of this process is the sodium-potassium ATPase (Na+K+-ATPase) enzyme located on the basolateral surface of epithelial cells and up-regulated during oedema resolution. We hypothesised that lung liquid clearance could be further up-regulated by lipid-mediated transfer and expression of exogenous Na+K+-ATPase cDNA. We demonstrate proof of this principle in a model of high permeability pulmonary oedema induced by intraperitoneal injection of thiourea (2.5 mg/kg) in C57/BL6 mice. Pretreatment of mice (24 h before thiourea) by nasal sniffing of cationic liposome (lipid #67)-DNA complexes encoding the alpha and beta subunits of Na+K+-ATPase (160 microg per mouse), significantly (P<0.01) decreased the wet:dry weight ratios measured 2 h after thiourea injection compared with control animals, pretreated with an equivalent dose of an irrelevant gene. Whole lung Na+K+-ATPase activity was significantly (P<0.05) increased in mice pretreated with Na+K+-ATPase cDNA compared both with untreated control animals as well as animals pretreated with the irrelevant gene. Nested RT-PCR on whole lung homogenates confirmed gene transfer by detection of vector-specific mRNA in three of four mice studied 24 h after gene transfer. This demonstration of a significant reduction in pulmonary oedema following in vivo gene transfer raises the possibility of gene therapy as a novel, localised approach for pulmonary oedema in clinical settings such as ARDS and lung transplantation.

Animals↗
PubMed1999

Effects of altering dosing on cationic liposome-mediated gene transfer to the respiratory epithelium.

Liposome-mediated gene transfer is currently sub-optimal with respect to both the extent and duration of transgene expression. We investigated whether simple changes in DNA dosing could enhance either of these outcomes. Increasing DNA doses produced highest transgene expression at an intermediate dose with toxicity observed at higher doses, thereby likely limiting expression. Adminis- tering an equivalent DNA dose in aliquots over a 1-3 day period resulted in significantly lower gene expression and did not increase the duration of expression. Administration at different times of the day (and hence wake/sleep cycles of the animals) did not alter gene expression. We conclude that such simple changes in dosing regimes are unlikely to contribute to improvements in gene transfer efficiency.

Animals↗
PubMed1999

Survival estimates for adults with cystic fibrosis born in the United Kingdom between 1947 and 1967. The UK Cystic Fibrosis Survey Management Committee.

BACKGROUND: The UK has published observed cohort survival figures for subjects with cystic fibrosis born since 1968. Prior to 1968 cohorts cannot be established directly from routine data as cystic fibrosis was classified with a number of unrelated conditions in ICD7. Reported here are interrupted survival curves from 1978 for patients with cystic fibrosis born before 1968. METHODS: Life tables for the three year cohorts born between 1947 and 1967 were constructed by firstly estimating the numbers of patients with cystic fibrosis born in each cohort from live birth data and the disease incidence. The number of the estimated cohort that had survived to 1978 is known, which enables the proportion surviving to 1978 to be calculated. The survival of these cohorts after 1978 can be calculated in the usual way. RESULTS: The survival for each successive cohort was better than that of the previous one, but most of the improvements appear to have taken place up to the age of about 20 years. Only 3% of the 1947-49 cohort survived to 30 years of age compared with 21% for the 1965-67 cohort, and 3% of the 1953-55 cohort survived to 40 years of age. For the later cohorts the mortality rate for those aged between 26 and 30 years appears to be about 50 per 1000 per year. CONCLUSIONS: While the trend in the numbers surviving into later adulthood is upwards, the mortality rates for these ages does not appear to be improving. It is not possible to tell from these data whether the high mortality rates in adulthood will improve with better resourced adult clinics or with improved treatment during childhood.

Adult↗
PubMed1998

Cystic fibrosis clinical trials.

The ion transport abnormalities in cystic fibrosis are becoming increasingly well defined, although how these lead to lung pathology is still speculation. Correction of these defects could theoretically be achieved either through pharmacological means or via gene therapy. Pharmacological approaches include increasing the amount of CFTR protein that reaches its correct localisation in epithelial cells. Secondly, approaches have been suggested which could increase the function of the protein already present at this correct localisation. Finally, it may be possible to identify alternative channels which could subserve the function of CFTR. Gene therapy is theoretically an attractive proposition as it should circumvent each of the identified abnormalities in cystic fibrosis. The principal difficulty at present relates to delivering sufficient copies of the normal CFTR gene into the appropriate cell population in vivo. A number of clinical trials have now been undertaken and steady and encouraging progress has been made in moving this approach from theory to practice.

Journal Article↗
PubMed1997

Incidence, population, and survival of cystic fibrosis in the UK, 1968-95. UK Cystic Fibrosis Survey Management Committee.

The UK Cystic Fibrosis Survey holds data on all people resident in the UK who were diagnosed as having cystic fibrosis and born either since 1968 or before 1968 and alive in 1977. Thus, incidence may be reported from 1968 and prevalence from 1977. The previous estimates are updated to the end of 1995 from data held in the database on 23 August 1996. The incidence is now calculated as one in 2415 live births. The 1992 mid-year population was 6500 people with 65% aged under 16 years. Births outnumber deaths by 160 per year, which suggests a population of 7750 by the year 2000, with all the increase being in the adult age range. The survival of successive cohorts continues to be better than earlier cohorts, the linear descent of the curves is still evident. The infant mortality rate for cystic fibrosis is now under 20 per thousand per year and early childhood mortality is under five per thousand per year. The crude mortality rate for 1995 was 21 per thousand per year, but the standardised mortality ratio was about 3300.

Adolescent↗
PubMed1997

Height and weight in cystic fibrosis: a cross sectional study. UK Cystic Fibrosis Survey Management Committee.

Cross sectional data reporting the height, weight, and body mass index of UK patients with cystic fibrosis are presented. During the first decade of life height and weight in patients with cystic fibrosis are maintained at about 0.5 SD below those of the general population, which reflects an improvement over earlier published observations. Postpubertal stature and weight maintenance in the cystic fibrosis population still show substantial deficits which may be related to treatment.

Adolescent↗
PubMed1996

Assessment of oxygen supplementation during air travel.

BACKGROUND: The aim of this study was to simulate an in flight environment at sea level with a fractional inspired concentration of oxygen (FiO2) of 0.15 to determine how much supplemental oxygen was needed to restore a subject's oxygen saturation (SaO2) to 90% or to the level previously attained when breathing room air (FiO2 of 0.21). METHODS: Three groups were selected with normal, obstructive, and restrictive lung function. Using a sealed body plethysmograph an environment with an FiO2 of 0.15 was created and mass spectrometry was used to monitor the FiO2. Supplemental oxygen was administered to the patient by nasal cannulae. SaO2 was continuously monitored and recorded at an FiO2 of 0.21, 0.15, and 0.15 + supplemental oxygen. RESULTS: When given 2 l/m of supplemental oxygen all patients in the 15% environment returned to a similar SaO2 value as that obtained using the 21% oxygen environment. One patient with airways obstruction needed 3 l/m of supplemental oxygen to raise his SaO2 above 90%. CONCLUSIONS: This technique, which simulates an aircraft environment, enables an accurate assessment to be made of supplemental oxygen requirements.

Aircraft↗