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Biomedical subjects

N Pearce

Publications and source records attributed to N Pearce.

At least 55 records · Page 3Linked to original sources
PubMed1991

Prescribed fenoterol and death from asthma in New Zealand, 1981-7: a further case-control study.

The association between inhaled fenoterol and death from asthma has been investigated further by studying 112 asthma deaths (cases) during 1981-7 in patients aged 5-45 years who had been admitted to a major hospital for asthma during the 12 months before death. Two age matched control groups were chosen. Control group A comprised 427 patients who had been admitted to hospital for asthma during the calendar year that the corresponding death occurred and who had also had a previous admission for asthma in the previous 12 months. Control group B comprised 448 patients admitted to hospital for asthma during the calendar year in which the admission of the corresponding case occurred. The inhaled fenoterol odds ratio was 2.11 (95% confidence interval (CI) 1.37-3.23, p less than 0.01) when group A was used as the control (the approach used in previous studies), and 2.66 (95% CI 1.74-4.06, p less than 0.01) with group B as the control (the approach recommended by critics of previous studies). Markers of chronic asthma severity were associated with asthma death when control group B was used, but not when control group A was used (which indicates that these markers were indirectly matched for when control group A was used). Information was also collected on various markers of acute asthma severity and prescription of psychotropic drugs, but it was found that these were not important confounders. These findings address the major criticisms of previous case-control studies of this issue, and add support to the hypothesis that inhaled fenoterol increases the risk of death in patients with severe asthma.

Administration, Inhalation↗
PubMed1991

Lack of evidence for beta-2 receptor selectivity: a study of metaproterenol, fenoterol, isoproterenol, and epinephrine in patients with asthma.

In order to investigate the pharmacodynamic selectivity of a number of beta-receptor agonists currently used in asthma, we compared the pulmonary and extrapulmonary effects of repeated inhalations of epinephrine, fenoterol, isoproterenol, and metaproterenol in 12 patients with asthma in a randomized double-blind crossover study. The drugs were administered from metered-dose inhalers at 15-min intervals for five doses (total dose, 10 puffs of each compound). Measurements of heart rate, blood pressure, total electromechanical systole (as a measure of inotropic response), QTc interval, plasma potassium, and FEV1 were made 5 min after each dose and 30 min after the final dose. Fenoterol and metaproterenol had significantly greater inotropic, electrocardiographic, chronotropic, and hypokalemic effects than did both isoproterenol and epinephrine. There was no difference in the bronchodilating effect of metaproterenol, fenoterol, or isoproterenol although these agents caused a significantly greater increase in FEV1 than did epinephrine. The concept of increasing beta-2 selectivity for metaproterenol and fenoterol compared with isoproterenol are not supported in the clinical setting.

Adrenergic beta-Agonists↗
PubMed1990

A comparison of the haemodynamic and hypokalaemic effects of inhaled pirbuterol and salbutamol.

In this double blind study, the cardiovascular and hypokalaemic effects of equal doses of inhaled pirbuterol and salbutamol were compared in eight healthy volunteers. Increasing doses of 200, 400, 600 and 800 micrograms (total dose 2000 micrograms) were given from a metered dose inhaler at 15 min intervals, followed by measurement of heart rate, blood pressure, total electromechanical systole (QS2I) (as a measure of inotropic response) and plasma potassium (K+) concentration 15 min after each inhalation. After inhalation of the highest concentration, salbutamol resulted in a greater increase in heart rate (10.5 bpm vs 4.4 bpm, p less than 0.0007), and reduction in QS2I (-25.4 ms vs -9.6 ms, p less than 0.0001) than pirbuterol. There were no significant differences in changes in systolic blood pressure (1.9 mmHg vs 6 mmHg, p = 0.27), diastolic blood pressure (-5.8 mmHg vs -3.9 mmHg, p = 0.64) or plasma K+ (-0.21 mmol/L vs -0.15 mmol/L, p = 0.57). We conclude that the new beta-2 adrenergic agonist pirbuterol is at least as beta-2 selective as salbutamol when administered by repeated inhalation in healthy volunteers.

Administration, Inhalation↗
PubMed1990

Trends in asthma mortality in New Zealand, 1908-1986.

Trends in mortality from asthma in non-Maori New Zealanders aged 5 to 34 years were examined for the period 1908-1986. Two previously documented epidemics of death from asthma occurred in the 1960s and the late 1970s. These epidemics are most likely to have been due to changes in the management of asthma: the introduction of isoprenaline forte by metered dose inhaler in the 1960s and inhaled fenoterol in the 1970s. A previously unreported rise in mortality, which was more gradual in onset and less severe, occurred in the 1940s and 1950s; a similar pattern occurred in England and Wales during the same period. It is unlikely that this increase in mortality was solely due to changes in diagnostic fashion or disease coding. Possible explanations include changes in the management or prevalence of asthma, or in environmental factors. It is notable that mortality was below 0.5 per 100,000 person-years prior to 1940, but has subsequently increased considerably. Thus, while modern methods for treating asthma have improved the quality of life of many asthmatics, mortality has increased during the period of their introduction and use.

Adolescent↗
PubMed1990

The self-administration of inhaled beta agonist drugs during severe asthma.

Interviews were conducted with 101 consecutive adult patients admitted to Wellington Hospital with a diagnosis of asthma to assess the extent to which beta agonist drugs are self-administered by asthmatic patients during severe asthma. The 99 patients prescribed an inhaled beta agonist were subdivided into two groups: group A comprising 79 patients prescribed a beta agonist for inhalation via an inhaler (metered dose aerosol or dry powder device) alone; group B comprising 20 patients prescribed beta agonist for inhalation via both an inhaler and nebuliser. In group A, the attacks of asthma lasted greater than 24 hours in 64/79 patients, and 22% of these patients reported taking more than 60 doses of their inhaler, and 52% more than 30 doses during the 24 hr period prior to admission. In group B, the attacks of asthma lasted greater than 24 h in 17/20 patients, and 35% of these patients self-administered their nebuliser more than six times, and 76% more than four times during the 24 h period prior to admission. In addition to their nebuliser use, these patients also took a median 23 doses of their inhaler during this 24 h period. This use of inhaled beta agonist contrasts with the recommended practice in both the USA and Europe, where most physicians recommend no more than 15 doses of a beta agonist as the maximal dose per day. We conclude that asthmatic patients in New Zealand self-administer high doses of inhaled beta 2 agonist drugs during severe exacerbations of asthma.

Adolescent↗
PubMed1990

Follow up of New Zealand participants in British atmospheric nuclear weapons tests in the Pacific.

OBJECTIVE: To study the health of Royal New Zealand Navy personnel who participated in atmospheric nuclear weapons tests conducted by the United Kingdom at Malden Island and Christmas Island in 1957 and 1958. DESIGN: Blinded, controlled follow up of up to 30 years. SETTING: New Zealand. SUBJECTS: 528 Men known to have participated in the tests and a control group of 1504 men who were in the Royal New Zealand Navy during the same period but did not participate in the tests. MAIN OUTCOME MEASURES: Mortality and incidence of cancer. RESULTS: Follow up for the period 1957-87 was 94% complete in test participants and 91% complete in the controls. There were 70 deaths among test participants and 179 deaths among controls, yielding a relative risk of 1.08 (90% confidence interval 0.85 to 1.38, p = 0.29). The relative risk of death from causes other than cancer was 0.96 (0.71 to 1.29, p = 0.59) whereas the relative risk of death from cancer was 1.38 (0.90 to 2.10, p = 0.09) and of the incidence of cancer was 1.12 (0.78 to 1.60, p = 0.29). For cancers other than haematological malignancies the relative risk was 1.14 (0.69 to 1.83, p = 0.31) for mortality and 1.01 (0.67 to 1.50, p = 0.48) for incidence. There were seven deaths from haematological cancers among test participants (relative risk 3.25, 90% confidence interval 1.12 to 9.64, p = 0.02), including four leukaemias (5.58, 1.04 to 41.6, p = 0.03). The relative risk for incidence of haematological cancers was 1.94 (0.74 to 4.84, p = 0.10) and that for leukaemia was 5.51 (1.03 to 41.1, p = 0.03). There were no cases of multiple myeloma in the test participants during the follow up period, but the expected number was only 0.3. CONCLUSIONS: Although the numbers are small, the findings for leukaemia are similar to those for British participants in the nuclear weapons test programme. Some leukaemias, and possibly some other haematological cancers, may have resulted from participation in this programme. There is little evidence of an increased risk for non-haematological cancers, and there is no evidence of an increased risk for causes of death other than cancer.

Cause of Death↗
PubMed1990

Epidemiologic studies of cancer in agricultural workers.

The incidence of cancer in agricultural workers is generally low, in part due to the low prevalence of cigarette smoking in this group. However, agricultural workers have elevated risks for several specific cancer types including leukemia, Hodgkin's disease, non-Hodgkin's lymphoma, multiple myeloma, and cancers of the lip, stomach, prostate, brain, and connective tissue. Two major groups of risk factors have been proposed as causes of hematologic malignancies in agricultural workers. The first group includes various agricultural chemicals. In particular, several studies have found increased risks of malignant lymphoma and soft tissue sarcoma in persons exposed to phenoxy herbicides. However, the evidence is inconsistent and there is a wide variation in relative risk estimates. The second group of risk factors includes various animal viruses. There is currently little evidence concerning the zoonotic nature or human carcinogenicity of these viruses. However, leads have been suggested by recent evidence of increased risks of hematologic malignancies in abattoir workers, veterinarians, and meat inspectors. A third hypothesis, for which little evidence is currently available, is that agricultural work may involve prolonged antigenic stimulus leading to lymphoproliferation. The factors responsible for the increased risks for cancers other than hematologic malignancies are not well understood but may also involve exposure to chemicals or viruses.

Abattoirs↗
PubMed1990

The pulmonary and extrapulmonary effects of inhaled beta-agonists in patients with asthma.

The cardiovascular, respiratory, and hypokalemic effects of repeated inhalation of fenoterol, albuterol, and isoproterenol were compared in 12 subjects with stable asthma according to a double-blind, crossover design. Ipratropium bromide served as a control providing bronchodilatation without extrapulmonary effects. Subjects inhaled the beta-agonists on an equal-weight basis (400 micrograms) at 0, 30, 40, and 45 minutes. Measurements of heart rate, blood pressure, total electromechanical systole (measure of inotropic activity), preejection period, QTc interval, plasma potassium levels, and forced expiratory volume in 1 second were made 5 minutes after each dose and again at 60 and 75 minutes. There were no differences in the bronchodilating effect between the beta-agonists. However, both fenoterol and isoproterenol resulted in greater positive inotropic stimulation than did albuterol, and fenoterol caused a greater fall in plasma potassium levels than did the other beta-agonists.

Adolescent↗
PubMed1990

White swans, black ravens, and lame ducks: necessary and sufficient causes in epidemiology.

Several authors have used Popper's "white swan" example to support arguments for a falsificationist approach to epidemiology. The statement "all swans are white" cannot be verified by finding even a large number of white swans, but can be falsified by finding a single black swan. An analogous epidemiologic example that has been proposed is the hypothesis that a particular virus is a necessary cause of acquired immunodeficiency syndrome (AIDS). Such examples, however, have little relevance to science since scientific theories are not generalizations of facts; rather, they involve an understanding of the underlying processes that cause certain facts to occur. Furthermore, the "white swan" example is particularly inapplicable to epidemiology, since most factors of scientific or public health importance are neither necessary nor sufficient causes of disease. Nevertheless, epidemiologic research has achieved success in the understanding and prevention of disease. These points are exemplified by applying Rothman's model of causal constellations, which provides a conceptual basis for the development of epidemiologic theories.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Cancer risks in painters: study based on the New Zealand Cancer Registry.

Painters are exposed to a range of complex chemical mixtures which include organic solvents and dye products with known carcinogenic and mutagenic potential. Trade painters or those manufacturing paints and coatings have increased rates of non-malignant diseases and cancers; including lung cancer, acute leukaemia, bladder cancer, and cancers of the oesophagus, larynx, biliary system, liver, skin, and large bowel. A series of case-control studies of painters, based on the New Zealand Cancer Registry, are presented. These concerned 19,904 male patients registered for the period 1980-4 who were aged 20 or older at the time of registration. For each cancer site studied, the registrants for all other cancer sites formed the control group. Three cancer sites were associated with work as a painter--namely, bladder tumours (odds ratio (OR) 1.52, 95% confidence interval (95% CI) 1.00-2.31), kidney and other urothelial tumours (OR 1.45, 95% CI 0.85-2.50), and multiple myeloma (OR 1.95, 95%, CI 1.05-3.65). Risks for multiple myeloma were greater among car or spray painters and signwriters (OR 2.81) compared with construction and general painters (OR 1.80). No increased risk was found for leukaemia or for respiratory, biliary, skin, or gastrointestinal cancers.

Adult↗