PubMed Health⌕ Search

Biomedical subjects

I R Martin

Publications and source records attributed to I R Martin.

16 recordsLinked to original sources
PubMed2004

Dopant distribution in a Tm(3+)-Yb(3+) codoped silica based glass ceramic: an infrared-laser induced upconversion study.

The optically active dopant distribution in a Tm(3+)-Yb(3+) doped silica based glass ceramic sample has been investigated. A systematic analysis of the upconversion fluorescence of the Tm(3+)-Yb(3+) codoped glass and glass ceramic has been performed at room temperature. Tm(3+) and Yb(3+) single doped glass and glass ceramics have also been included in the study. Upon infrared excitation at 790 nm into the (3)H(4) level of the Tm(3+) ions a blue upconversion emission is observed, which is drastically increased in the Yb(3+) codoped samples. A rate equation model confirmed the energy transfer upconversion mechanism. Based on these results, the temporal dynamic curves of the levels involved in the upconversion process, (3)H(4), (2)F(5/2), and (1)G(4) were interpreted in the glass ceramic samples. The contribution of the optically active Tm(3+) and Yb(3+) ions in the crystalline and in the vitreous phase of the glass ceramic was distinguished and the ratio of Tm(3+) ions in the crystalline phase could be quantified for the 1 mol % Tm(3+)-2.5 mol % Yb(3+) glass ceramic. A surprising result was obtained for that concentration: the main contribution to the upconversion emission of the glass ceramic is due to Tm(3+)-Yb(3+) ions in the vitreous phase.

Journal Article↗
PubMed2004

Care plans for acutely deteriorating COPD: a randomized controlled trial.

INTRODUCTION: Acute exacerbations of chronic obstructive pulmonary disease (COPD) are a frequent reason for admission to hospital and are responsible for the majority of the direct economic costs of treating COPD. AIMS: To test whether an individualized care plan for patients experiencing acute exacerbations of COPD result in reduced health care utilization and improved quality of life for patients. METHODS: Ninety-two patients with confirmed COPD were selected by general practitioners or district nurses, and randomly assigned to care plan or usual care groups. The care plan was developed in collaboration with general practitioners, secondary care specialists, specialist nurses, ambulance service providers and the after hours clinic. Patients were followed for 12 months, and the primary end-points were frequency of use of primary care services and hospital admissions. RESULTS: There was no significant reduction in hospital admissions or improvement in quality of life in the group of patients who used the care plan compared to controls. The care plan group called out the ambulance service more frequently [2.8 (1.3, 4.3) versus 1.1 (0.7, 1.5) calls per 12 months; P = 0.03], and there was a trend towards greater use of oral prednisone [2.3 (1.4, 3.2) versus 1.3 (0.8, 1.8) courses per 12 months; P = 0.06]. CONCLUSION: In contrast to asthma, the provision of individualized self-management plans, whose content was enhanced to provide guidance to carers and health care professionals, did not reduce health care utilization or improve overall quality of life during acute exacerbations of COPD. Other strategies are required.

Aged↗
PubMed2000

Nosocomial pneumonia in adult general medical and surgical patients at Christchurch Hospital.

AIMS: To determine the incidence, microbial cause, and outcome of nosocomial pneumonia in adult general medical and surgical patients at Christchurch Hospital. METHOD: A one-year prospective study of consecutive patients developing nosocomial pneumonia in a university-affiliated hospital. Expanded diagnostic laboratory testing was undertaken to identify the microbial cause of pneumonia. RESULTS: We recruited 126 patients, which represented an incidence of 6.1 per 1,000 admissions. Only 52 (41%) patients submitted sputum that satisfied the cytological screening criteria for testing. A microbial cause was identified in 47 cases (37%): the most common was Legionella spp. (sixteen cases), followed by Influenza A (six cases) and Staphylococcus aureus (four cases). We did not identify an environmental source of the Legionella species. Fourteen patients (11%) died as a consequence of pneumonia and nearly all of these had significant comorbidity. Renal impairment, alcohol excess, and severity of pneumonia were the most powerful predictors of a fatal outcome by univariate analysis. CONCLUSIONS: In most patients we did not identify a microbial cause of pneumonia; when we did, Legionella species were the most common, although this micro-organism has a long incubation period so some subjects may have acquired it before admission. These results guide preventative efforts, diagnostic testing and selection of antimicrobial therapy for nosocomial pneumonia in our hospital.

Adult↗
PubMed1998

Cat allergen levels in public places in New Zealand.

AIMS: Cat allergen (Fel d 1) is a known risk factor for asthma. Studies have demonstrated Fel d 1 in both public buildings and domestic dwellings where cats have never been. The aims of this study were to measure reservoir Fel d 1 levels in public buildings in New Zealand, to examine determinants of these levels and to compare them with previously measured domestic levels. METHODS: Dust was obtained in two centres (Wellington and Christchurch) from hotels, hospitals, rest homes, churches, primary schools, childcare centres, cinemas, bank head offices and aeroplanes; and from North Island ski lodges. Measurements of temperature and relative humidity were taken. Information was collected on building characteristics. Fel d 1 levels (microg/g of fine dust) for floors (n=203), beds (n=64) and seats (n=24) were expressed as geometric means (95% confidence intervals). RESULTS: Detectable Fel d 1 levels were found in 95% of floor samples, 91% of bed samples and 100% of seat samples. Fel d 1 levels [geometric mean (95% confidence intervals)] were significantly higher on cinema and domestic aircraft seats [36.8 (20.8-65.3) microg/g and 33.3 (28.0-39.7) microg/g respectively] than on floors [3.6 (2.5-5.1) microg/g and 2.4 (1.8-3.0) microg/g respectively]. Floor Fel d 1 levels in the public buildings sampled were lower than those of domestic dwellings without cats [0.9 (0.6-1.4) microg/g vs 1.7 (1.2-2.4)] microg/g in Wellington and [2.0 (1.6-2.6) microg/g vs 4.0 (2.7-6.0] microg/g in Christchurch. After controlling for potential confounders, floor Fel d 1 levels were higher with carpeted floors (p<0.001) and lower in banks and hospitals (p<0.001). CONCLUSION: Fel d 1 levels in public buildings are low in New Zealand public places except for cinema and domestic aircraft seats where all but one sample had Fel d 1 levels potentially high enough to precipitate asthma symptoms in sensitised individuals.

Air Pollution, Indoor↗
PubMed1997

House dust mite and cat allergen levels in domestic dwellings in Christchurch.

AIMS: To quantify the levels of Dermatophagoides pteronyssinus allergen (Der p I) and Felis domesticus allergen (Fel d I) in domestic dwellings in Christchurch and to assess possible relationships with housing characteristics. METHODS: Domestic dwellings (n = 93) were randomly selected and housing characteristics documented during the summer of 1994/95. Dust samples were obtained from the floor of the living room (LR) and bedroom (BR) and from the bed by standard vacuuming methods. The predominant mite species were determined and D pteronyssinus and F domesticus levels quantified. RESULTS: D pteronyssinus was the predominant (95%) species. D pteronyssinus allergen levels [geomean (95% confidence intervals) were 3.5(2.5-4.8) micrograms/g in LR, 10.1(7.5-13.7) micrograms/g in BR and 5.7(4.3-7.6) micrograms/g in the bed. F domesticus allergen levels were significantly higher (p < 0.001) in houses with cats than without cats [median (range) 93.2 (3.3-1227.2) micrograms/g and 2.9 (0.4-214.8) micrograms/g respectively]. Higher LR D pteronyssinus allergen levels were found in houses classified as having high indoor humidity and in houses situated in geographically damp locations. CONCLUSIONS: Domestic D pteronyssinus and F domesticus allergen levels in Christchurch are comparable with those found in other climatically similar locations. D pteronyssinus allergen levels are associated with both indoor and outdoor humidity factors.

Adult↗
PubMed1997

Respiratory effects of air pollution in chronic obstructive pulmonary disease: a three month prospective study.

BACKGROUND: A study was undertaken to investigate the relationship between air pollution levels and respiratory symptoms and peak expiratory flow rate (PEFR) in subjects with chronic obstructive pulmonary disease (COPD) living in Christchurch, New Zealand. METHODS: Forty subjects aged over 55 years with COPD completed twice daily diaries for three months during the winter of 1994. Subjects recorded respiratory symptoms, PEFR, outdoor activity, visits to doctor or hospital, and medication use. All were resident within a 5 km radius of the regional council's air pollution monitoring site. Daily and hourly mean pollutant levels (particulates (PM10, nitrogen dioxide (NO2), sulphur dioxide (SO2) and carbon monoxide (CO)) were measured at the monitoring site. RESULTS: Pollution levels were generally low relative to those recorded in previous years. The New Zealand Ministry for the Environment guidelines for PM10 were exceeded on five occasions, and for CO six times. No association was found between PEFR and any of the pollution variables. A rise in the PM10 concentration equivalent to the interquartile range was associated with an increase in night time chest symptoms (relative risk 1.38, 95% CI 1.07 to 1.78). A rise in NO2 concentrations equivalent to the interquartile range was associated with increased reliever inhaler use (relative risk 1.42, 95% CI 1.13 to 1.79) and for 24 hour lag analysis with increased nebuliser use (relative risk 2.81, 95% CI 1.81 to 4.39). There was no increase in the relative risk of other symptoms in relation to pollution levels. CONCLUSIONS: These effects, demonstrated in a small susceptible group of subjects with COPD, indicate that adverse outcomes can be measured in response to pollution levels that are within current guidelines.

Aged↗
PubMed1997

Climate and aeroallergen levels in asthma: a 12 month prospective study.

BACKGROUND: There is evidence to suggest that changes in weather and airborne fungal spore and pollen counts may affect asthma symptoms. METHODS: The relationship between climate, airborne fungal spore, and pollen counts and peak expiratory flow rate (PEFR) and asthma symptoms was prospectively investigated in a population of mild to moderate asthmatic subjects in Blenheim, New Zealand. Subjects recorded twice daily PEFR measurements and asthma symptom scores for up to one year. Spore and pollen counts were measured two hourly and meteorological data were measured hourly. Individual, within person, multiple linear regression analyses were conducted, adjusting for auto-correlation. A random effects model was assumed for the individual regression co-efficients and weighted estimates of the mean of these coefficients were obtained by the method of maximum likelihood. RESULTS: One hundred and thirty nine asthmatic patients (60% atopic) aged 17-80 years completed the study. Of the weather variables, only temperature showed a small but consistent association with PEFR. The mean rise in PEFR for an 8.8 degrees C (2 SD) change in temperature was 0.78% (95% CI 0.44% to 1.11%), approximately 3.0 l/min. There was a weak association between days of high basidiospore counts and increased nocturnal wakening and reliever medication use. Pollen counts showed no consistent association with either PEFR or asthma symptoms. CONCLUSIONS: The results of this study suggest that the effects of weather and aeroallergens on PEFR and asthma symptoms in this population are small, and that other causes need to be sought to account for variations in asthma severity and exacerbations.

Adolescent↗
PubMed1996

Asthma management at Christchurch Hospital: compliance with guidelines.

AIM: To audit compliance with guidelines for the assessment and management of adult patients admitted to Christchurch Hospital with acute asthma. METHODS: An asthma admission form and management guidelines, based on international consensus statements, were designed for use by resident staff at Christchurch Hospital. Compliance with these guidelines was audited during the winter of 1994 by means of retrospective case record review. RESULTS: One hundred and forty three admissions were screened. The form was used in 99 patients (69%), of which 97 had records available for audit. Sixty two patients were admitted under general medical services and 35 under respiratory specialist services. The median age was 34 years (range 14-84) and 77% were female. The history including interval status was adequately documented in over 95% of cases. Peak flow rate was recorded on admission in 93 patients (96%) and spirometry in 62 (64%). During the acute phase of treatment 528 items were prescribed, of which 382 (72%) were appropriate according to the guidelines. The major area (55%) of nonguideline prescribing was the use of nebulised ipratropium in addition to salbutamol for mild or moderate asthma. Written evidence of asthma education was present in 42 (43%). In 34 patients (35%) there was specific reference to the introduction of an asthma action plan. Of the 33 smokers only 17 appeared to have been given smoking cessation advice. Discharge prescribing complied with the guidelines in 71%. The most common variation from the guidelines for discharge therapy related to the manner of prednisone dose reduction. The readmission rate at 1 month was 11%. CONCLUSIONS: The introduction of an asthma admission form enhanced the quality of clinical data gathering by junior staff. Compliance with management guidelines was adequate. Specific sections pertaining to the use of chest radiographs, arterial blood gases and the prescribing of ipratropium and prednisone will be reviewed in updated guidelines.

Adolescent↗
PubMed1996

Community acquired pneumonia: aetiology and usefulness of severity criteria on admission.

BACKGROUND: Community acquired pneumonia remains an important cause of hospital admission and carries an appreciable mortality. Criteria for the assessment of severity during admission have been developed by the British Thoracic Society (BTS). A study was performed to determine the sensitivity and specificity of a severity rule based on a modification of the BTS prognostic rules applied on admission, to compare severity as assessed by medical staff with the modified rule, and to determine the microbiological cause of community acquired pneumonia in Christchurch. METHODS: A 12 month study of all adults admitted to Christchurch Hospital with community acquired pneumonia was undertaken. Three hundred and sixteen consecutive patients with suspected community acquired pneumonia were screened for inclusion. Variables obtained from the history, examination, investigations, and initial treatment were examined for association with mortality. RESULTS: Two hundred and fifty five patients met the inclusion criteria. Their mean age was 58 years (range 18-97). A microbiological diagnosis was made in 181 cases (71%), Streptococcus pneumonia (39%), Mycoplasma pneumoniae (16%), Legionella species (11%), and Haemophilus influenzae (11%) being the most commonly identified organisms. Patients had a 36-fold increased risk of death if any two of the following were present on admission: respiratory rate > or = 30/min, diastolic BP < or = 60 mm Hg, urea > 7 mmol/l, or confusion. The severity rule identified 19 of the 20 patients who died and six of eight patients admitted to the intensive care unit as having life threatening community acquired pneumonia. The sensitivity of the modified rule for predicting death was 0.95 and the specificity 0.71. In 47 cases (21%) the clinical team appeared to underestimate the severity of the illness. CONCLUSIONS: The organisms responsible for community acquired pneumonia in Christchurch are similar to those reported from other centres except for Legionella species which were more common than in most studies. The modification of the BTS prognostic rules applied as a severity indicator at admission performed well and could be incorporated into management guidelines.

Adolescent↗
PubMed1994

An audit of the assessment and management of patients admitted to Christchurch Hospital with chronic obstructive pulmonary disease.

AIM: To audit the assessment and management of patients admitted to hospital with chronic obstructive pulmonary disease (COPD) during three months of the winter of 1992. METHODS: Consensus management guidelines were developed as the basis for the audit. Consecutive cases were audited by review of the case notes. Half were admitted initially under a respiratory physician and half under a general physician. Ninety-five cases were audited. RESULTS: The overall standard of medical assessment was adequate but a number of deficiencies were identified. The mean duration of stay in hospital was nine days. In the emergency department the use of pulse oximetry in preference to arterial blood gas analysis led to failure to diagnose significant ventilatory failure in five cases. Initial assessment by junior medical staff failed to include comment about level of consciousness in 50% of cases and chest hyperinflation in 40%. Oxygen therapy was given in 87% of cases, but was not prescribed in one third and was often not adequately monitored. Peak flow monitoring was performed on admission in 74% of cases and arterial blood gas measurement in 81%. Over 90% of patients were given nebulised bronchodilator therapy with both nebulised ipratropium bromide and salbutamol. Antibiotics were given in 77% of cases. Corticosteroids were given in 95% of cases, usually orally. Sedatives were prescribed inappropriately in six cases where there was acute ventilatory failure. Four patients died in hospital, none unexpectedly. Three patients were mechanically ventilated and all survived to leave hospital. There was no discharge summary in the case records in 29% of cases. CONCLUSIONS: Standards of assessment and treatment were adequate. Several areas were identified where improvements are required, particularly in the prescribing and monitoring of oxygen therapy. Hospital-wide guidelines for the management of COPD are to be developed.

Adrenal Cortex Hormones↗
PubMed1993

[Combination heart-lung transplantation in children: 4-year experience in London].

Since 1987, 21 children under 16 years of age have undergone combined heart and lung transplantation at Great Ormond Street Hospital, London. All children had terminal pulmonary or cardiopulmonary disease. Eight children died one day to 21 months after operation. Actuarial survival was 76% (SEM 10) at 1 year and 60% (SEM 12) at 3 and 4 years after transplantation. 13 children were alive, and all took part in all age-appropriate activities.

Adolescent↗
PubMed1991

Heart and lung transplantation for terminal cystic fibrosis. A 4 1/2-year experience.

From among 112 patients with cystic fibrosis who were assessed for heart-lung transplantation, 83 were accepted. Twenty-six died while awaiting heart-lung transplantation and 32 had the operation. The management and the outcome of these 32 patients is reported. Survival, infection, and rejection rates among these patients were compared with those of 61 patients without cystic fibrosis who underwent heart-lung transplantation between 1984 and 1990. The cumulative survival rate was 72.29% +/- 94.91% at 1 year and 55.59% +/- 7.50% at 3 years. The mortality rate was slightly higher in the group with cystic fibrosis during the first year after the operation but it was lower at 3 years. The difference, however, could have been due to chance alone (p = 0.308). The same was true for the prevalence of rejection (up to 6 months: chi 2 = 1.8141, p = 0.17), and infection (up to 6 months: chi 2 = 2.20, p = 0.14), between the two groups. It is concluded that cystic fibrosis does not constitute an additional risk in terms of survival and morbidity after heart-lung transplantation.

Adolescent↗
PubMed1986

Progressive non-infectious anterior vertebral fusion.

Four cases of progressive non-infectious anterior vertebral fusion are described. Three cases remain relatively asymptomatic, but one has developed spinal cord compression secondary to an acute angled kyphosis. The clinical, radiological, and pathological features are reviewed and some comparisons with the spinal changes in thalidomide embryopathy are made.

Adolescent↗
PubMedDate not supplied

Tumour presenting as a retrosternal abscess following median sternotomy.

A 73-year-old lady, who underwent coronary artery bypass grafting eight months previously, presented with rigors and chest pain. The upper sternum was tender, swollen and erythematous, suggesting a retrosternal abscess. Radiological investigation supported the clinical diagnosis. Local infections following median sternotomy are uncommon, most being early and superficial. Late infections are very uncommon, and should suggest alternative pathology. Following open surgical drainage, histology showed the mass to be a poorly differentiated adenocarcinoma. The primary tumour was never found.

Abscess↗