Evaluation of a new Aerodynamic Particle Sizer Spectrometer for size distribution measurements of solution metered dose inhalers.

The ability of the Model 3320 and newer Model 3321 Aerodynamic Particle Sizer Spectrometer (APS) to make accurate mass-weighted size distribution measurements of solution metered dose inhalers (MDIs) was evaluated. Measurements of experimental HFA-134a beclomethasone dipropionate MDIs were made with both the APS 3320 and APS 3321 and compared to the Andersen Cascade Impactor (ACI). The mass-weighted size distribution measurements from the ACI and APS 3321 agreed well but were very different than the APS 3320 measurements. Evaluation of the APS 3320 size distribution measurements indicated that the presence of a few erroneous particle measurements caused a gross overestimation of the mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD). When a previously described technique was used to eliminate erroneous particle size measurements from the size distribution calculation, the MMAD and GSD from the APS 3320 agreed well with those from the ACI and APS 3321. The GSD from the APS 3321 and the APS 3320 after a mask was applied were slightly larger than from the ACI. It is believed that both APS instruments slightly underestimate the GSD while the ACI slightly overestimates the GSD. Further experiments were conducted using the APS 3321 to examine the influence of drug concentration and cosolvent level on the size distribution of solution formulation MDIs. The MMAD was shown experimentally and theoretically to be proportional to drug concentration to the one-third power. Cosolvent concentration had minimal influence on MMAD over the range examined. The measurements reported in this paper demonstrate that it is possible to obtain accurate mass-weighted size distribution measurements with the APS 3320 and APS 3321. These instruments allow for accurate size distribution measurements to be made in minutes as opposed to the hours required to conduct and analyze size distribution measurements from cascade impactors.     

Set-up variation of patients treated with radiotherapy to the prostate measured with an electronic portal imaging device

The set-up variation of 11 patients treated supine with radical radiotherapy for carcinoma of the prostate was measured with an electronic portal imaging device to determine the adequacy of set-up techniques and current margins, as well as the need for immobilization. During the treatments 172 images of the anterior fields and 159 images of the left-lateral fields were taken and the errors in treatment placement were measured by template matching. The variation in the superior-inferior direction was small, 1.4-1.6 mm (1 SD), while the medio-lateral variation was 2.8 mm (1 SD). The anterior-posterior variation was largest, 4.6 mm (1 SD) with an offset of 3.3 mm anterior. This anterior offset and large anterior-posterior variation suggests that set-up techniques were not optimal for this direction. The 1 cm margin used was adequate for set-up variation except in a small number of cases, which was mainly due to the anterior trend. Random (treatment-to-treatment) variations were small (1.1-2.3 mm; 1 SD), indicating that immobilization would result in only modest improvement in reproducibility for these supine patients.     

Radioimmunoassay of factor V in human plasma and platelets

Homogeneous, single-chain human factor V was used to develop a double antibody competition radioimmunoassay to measure factor V concentrations in plasma and platelets. Standard curves were constructed that allow for the detection of as little as 20 ng factor V/ml of plasma. Normal factor V concentrations range from 4 to 14 micrograms/ml of plasma with an average value of 7.0 +/- 2.0 micrograms/ml (n = 64). No correlation was observed between antigen levels and age or sex. The radioimmunoassay data are consistent with factor V clotting assays, providing freshly drawn plasma is used in the bioassay. Radioimmunoassay of washed platelets indicate that 0.63-1.93 microgram of factor V is present per 2.5 X 10(8) platelets (4612-14128 molecules of the factor V platelet). When normalized to individual hematocrits and platelet count, the data indicated that platelets contribute approximately 18%-25% of the factor V found in whole blood. In addition, two individuals with functionally deficient factor V were examined and found to be deficient in both antigen and activity.     

Trends in lung cancer incidence in Sweden with special reference to period and birth cohorts

Objective: Sweden has one of the largest population-based cancer registers in the world that provides an opportunity to examine the trend of lung cancer incidence during a 35-year period. The primary aim of the present study was to estimate the effects of birth cohort, year of diagnosis (period), and age on the time trends of lung cancer incidence rates, and to analyze the gender-specific incidence of different histopathological types of lung cancer. Results: Among men the age-standardized incidence rate increased steadily up to 1982, when a peak of 49 cases per 100,000 person-years was reached. Among women the incidence rate was lower and showed a monotonic increase throughout the observation period. The fastest rate of increase was noted among the youngest women. In women, but not in men, there was a steady increase in risk with each successive birth cohort. For both sexes there were large changes in the histopathological distributions of cases. The most notable was a major increase in adenocarcinomas. Conclusions: The overall age-adjusted incidence rate of lung cancer in Sweden has stabilized in men during the past two decades while rates are still increasing in women. In view of the continued high prevalence of smoking among young women, a future definite increase in the overall number of lung cancer cases in women can be expected.     

Outcome after lung cancer surgery. Factors predicting early mortality and major morbidity.

OBJECTIVE: This study was undertaken to assess mortality, complications and major morbidity during the first 30 days after lung cancer surgery and to estimate the significance of presurgical risk factors. METHODS: The study was based on all patients referred for surgery for primary lung cancer from 1 January 1987 to 1 September 1999. There were in total 616 patients with primary lung cancer. Three-hundred and ninety-four were men and 222 women. Postoperative events studied were divided into major and minor complications or death during the first 30 days after surgery. The significance of risk factors for an adverse outcome (defined as death or major complication in the first 30 days postoperatively) was assessed by uni- and multivariate logistic regression analyses. RESULTS: During the study period an increasing number of women and of patients older than 70 years underwent surgery. Overall 30-day mortality was 2.9, 0.6% after single lobectomy and 5.7% after pneumonectomy. Major complications occurred in 54 patients (8.8%). Fifty-eight patients (9.5%) had an adverse outcome during the first 30 days. Male gender, smoker, FEV(1)< or =70% of expected value, squamous cell carcinoma and pneumonectomy were risk factors predicting adverse outcome in the univariate model. Pneumonectomy and FEV(1)< or =70%, were the only independently significant factors for adverse outcome. Only pneumonectomy was independently associated with an increased risk for early death. CONCLUSION: Our results show low mortality and morbidity after lung cancer surgery. However, patients with reduced lung capacity and those undergoing pneumonectomy should be treated with great care, as they run a considerable risk of major complications or death during the first 30 days postoperatively. Older age (>70 years) does not appear to be a contraindication to lung cancer surgery, but patients in this group should undergo careful preoperative evaluation.     

Attitudes to the provision of primary health care at the day hospitals in Cape Town

Day hospitals in Cape Town are examined against the criteria in the definition of primary health care of the World Health Organization's Declaration of Alma Ata. A survey of patients attending a day hospital was undertaken to ascertain the consumer perspective regarding access to and quality of the service offered. The provider's perspective was obtained from secondary sources and in-depth interviews. It was found that the services are generally acceptable to the users, but that factors such as waiting time and transport create problems for patients. Community participation is also very limited. The separation of preventive and curative services also places limitations on the day hospitals--they provide only curative health care. The most important reason given by patients for using the day hospitals is the low cost.