Search PubMed⌕ Search

Biomedical subjects

G Boyd

Publications and source records attributed to G Boyd.

At least 73 records · Page 4Linked to original sources
PubMed1989

Obstructive airways disease in non-smoking subjects with pigeon fanciers' lung.

The aim of the study was to assess the degree of airways involvement in non-smoking subjects with extrinsic allergic alveolitis resulting from pigeon-derived antigens. Two hundred and eight pigeon fanciers completed a questionnaire of symptoms, performed spirometry on a Vitalograph Compact spirometer and had IgG antibody to pigeon gamma-globulin measured. Eighty fanciers had the acute form of pigeon fanciers' lung (PFL) and these subjects were less likely to be current smokers (P less than 0.001). Subjects with PFL had a higher prevalence of chronic bronchitis (P less than 0.001), large airways (P = 0.014) and peripheral airways obstruction (P less than 0.001). The prevalence of chronic bronchitis and peripheral airways obstruction increased significantly as the level of antibody to pigeon gamma-globulin rose. Peripheral airways obstruction, as manifest by a reduced FEF25-75%, was the most common abnormality found. Airways disease is an important feature of the acute form of PFL and consists of a hypersecretory disorder in the form of chronic bronchitis and of obstructive airways disease particularly affecting the peripheral airways.

Adolescent↗
PubMed1989

Climate, intermittent humidification, and humidifier fever.

Two summer outbreaks of humidifier fever (HF) are described in a microprocessor factory (factory A) and a printing factory (factory B). The air in each factory was humidified intermittently and controlled by present humidistats operating to maintain a relative humidity of 45% by an air handler incorporating a spray humidifier in factory A and two ceiling mounted spray humidifiers in factory B. Questionnaire data from each workforce suggested that although symptoms apparently occurred most commonly in both factories on return from holiday (41/57, 71.9%), many subjects (24/40, 60%) in factory A also had intermittent symptoms of ill defined periodicity for some time before the disorder was recognised. Similar intermittent symptoms with no discernible pattern occurred in factory B in a smaller number of subjects (4/17, 23.5%), all of whom were night or rotating shift workers. Both episodes of humidifier fever after return from summer holiday developed when nocturnal air temperatures were unseasonably low; not on the day of return to work but two days later (factory A) and one day later (factory B). Symptoms were most common in most workers who had circulating serum IgG antibody measured by ELISA to humidifier sludge in factory B (14/17, 82.9%) but were most common in IgG antibody negative subjects in factory A (27/40, 67.5%). A more classic form of humidifier fever redeveloped in factory B during winter when meteorological recordings suggested that humidification of intake air was more continuous. Humidifier fever in winter may have been the major influence on the formulation of the symptom pattern thought to be relevant for recognition of the disorder. A form of the illness, however, can occur during the summer which is camouflaged by intermittent humidification when the symptoms appear to be more closely associated with cool nocturnal air intake and unrelated to the pattern of attendance at work.

Air Conditioning↗
PubMed1989

Longitudinal course of extrinsic allergic alveolitis in pigeon breeders.

The purpose of this study was to assess the longitudinal course of pigeon breeders' disease by evaluating 24 patients with the acute form of the disease 10 years after their original diagnosis. Twenty one patients attended for clinical assessment, pulmonary function studies, chest radiography, and antibody measurement. Eighteen had continued to keep pigeons, emphasising their commitment to the hobby. Despite continued antigen exposure pigeon related symptoms had improved in most patients and only five still had troublesome symptoms. Four patients had residual abnormalities of pulmonary function or chest radiographs and three had chronic bronchitis. Fanciers had attempted to regulate their exposure to the birds by use of masks and by spending less time in their lofts but this is an unlikely explanation for the benign course of their disease, as levels of antibody to pigeon gammaglobulin remained high, suggesting that appreciable antigen exposure was still occurring. In most cases a state of equilibrium between host and antigen appeared to have developed. This observation has implications for the clinical management and understanding of the nature of the disease.

Adult↗
PubMed1989

Chronic simple bronchitis in pigeon fanciers. Relationship of cough with expectoration to avian exposure and pigeon breeders' disease.

The prevalence of chronic bronchitis and its relationship to antigenic exposure was studied in a population of pigeon fanciers. Two hundred and eighty seven fanciers completed a questionnaire regarding symptoms and circumstances of avian exposure and had IgG antibody to pigeon gammaglobulin measured by an enzyme linked immunosorbent assay. Chronic bronchitis occurred in 26.2 percent of nonsmoking fanciers and increased in prevalence as antibody levels rose (p less than 0.001). Although significantly more common (p less than 0.005) in the 85 (29.6 percent) fanciers who also had typical delayed symptoms of pigeon breeders' disease (PBD), chronic bronchitis was the only manifestation of the disease in 24 (8.4 percent) of the population surveyed. Chronic bronchitis was not related to the intensity or duration of avian exposure suggesting that host factors are more important in its pathogenesis. Chronic bronchitis must be considered to be an integral part of the clinical spectrum of PBD.

Adolescent↗
PubMed1989

Smokeless tobacco use among adolescents: a theoretical overview.

Prevalence data that are currently available indicate that smokeless tobacco use among youths in various parts of the United States is a significant and growing problem. Although relatively little is known about the factors that contribute to the initiation and maintenance of this behavior, previous research focusing on other substance use provides a valuable framework for both a study of smokeless tobacco use and the design of effective interventions for its prevention. The papers presented in this monograph address many of the gaps in our current knowledge and provide an accurate overview of research efforts in this area to date.

Adolescent↗
PubMed1988

Effect of cigarette smoking on the specific antibody response in pigeon fanciers.

Titres of circulating IgG antibodies to pigeon gammaglobulin and end expired carbon monoxide concentrations were measured in 86 pigeon fanciers attending the "Show of the Year." Antibody levels were significantly higher in non-smokers and in those with end expired carbon monoxide concentrations below 10 parts per million.

Alveolitis, Extrinsic Allergic↗
PubMed1987

Use of smokeless tobacco among children and adolescents in the United States.

Data collected by National Cancer Institute grantees on the use of smokeless tobacco by youth are reported. Self-reports were collected from over 43,000 students from grades 4 through 11 in 16 locations in the United States and 1 location in Canada. Lifetime and recent use of smokeless tobacco are reported by location, sex, grade level, and ethnic group. Use of smokeless tobacco increased with grade level. Typically, 40 to 60% of males had tried smokeless tobacco, and in most locations, 10 to 20% of older male youths reported recent use. With the exception of Native Americans, rates of use among females were lower than those among males. Use was highest among Native Americans and lowest among blacks and Asians. Smokeless tobacco use by Hispanics was comparable to that by whites. Collectively, the data indicate that large numbers of male youths in many areas of the United States are using smokeless tobacco. In light of recent research on the health consequences of using smokeless tobacco, the health of these youth may be endangered.

Adolescent↗
PubMed1987

Serological and clinical investigation of humidifier fever.

A group of nineteen normally healthy subjects in a microprocessor factory reported various degrees of work-related respiratory and systemic symptoms that in some were suggestive of humidifier fever (HF). They all had normal serology against a variety of infectious agents, but serum-precipitating antibody against antigens in the factory humidifier water was present in twelve subjects, primarily those with symptoms most in keeping with HF. There was extensive serological identity between the antigens from this and other confirmed sources of HF. The antibody-positive subjects were all non-smokers and had significantly raised serum IgG. Nine months later, following modification of the humidifier system, the symptoms had resolved in fourteen of the nineteen subjects, the precipitins were reduced in seven but persisted in five subjects, and the total IgG levels were significantly reduced in all subjects. The measurement of total, as well as specific, IgG may be of value in assessing this disease.

Adult↗
PubMed1986

Diagnostic role of gastrointestinal hormones in patients with chronic pancreatitis.

Thirty-three patients with chronic pancreatitis were studied in an effort to correlate release of gastrointestinal hormones (GIH) with the degree of pancreatic insufficiency. A prospective examination was conducted of fat-stimulated release of pancreatic polypeptide (PP), cholecystokinin (CCK), and neurotensin. Seventy-two-hour fecal fat determination, endoscopic retrograde pancreatography (ERP), and the bentiromide-PABA test were used to correlate the clinical stage of disease. The ERP was classified as positive only if the changes were advanced (or "marked") according to the Cambridge Classification. Five patients were defined to have mild disease, 13 moderate, and 15 severe. Any patient with clinical evidence of chronic pancreatitis and ERP changes that were less than advanced and had normal fecal fat and bentiromide tests received a grade of mild. Patients with one abnormal test were graded moderate, and those with two or three abnormal results were graded severe. In the 33 patients, the integrated 60-minute release of pancreatic polypeptide (PP) was 37.4 +/- 6.1 ng-60 min/ml in those five patients with mild disease, 102.3 +/- 10.3 ng-60 min/ml in the 13 patients with moderate disease, and 7.6 +/- 2.2 ng-60 min/ml in the 15 patients with severe disease. The integrated 60-minute release of neurotensin was 3.8 +/- 0.4 ng-60 min/ml in mild disease, 2.0 +/- 0.3 ng-60 min/ml in moderate disease, and 0.2 +/- 0.1 ng-60 min/ml in severe disease. CCK release did not correlate with the severity of disease. Enhanced release of PP appeared to correlate well with moderate stage of chronic pancreatitis, and depressed PP release with severe disease. Stimulated levels of PP and neurotensin appear to be useful in the diagnosis and staging of chronic pancreatitis. It is concluded that measurement of fat-stimulated release of PP and neurotensin may be useful to assess severity of disease in patients with chronic pancreatitis.

Adult↗
PubMed1986

Relationships between avian exposure, humoral immune response, and pigeon breeders' disease among Scottish pigeon fanciers.

In a large scale clinical survey of Scottish pigeon fanciers, 277 people completed a detailed questionnaire and provided a venous blood sample. There were 29 (10.4%) who fulfilled the clinical criteria for pigeon breeders' disease used in the study and 84 (30.3%) who showed a significant serum IgG antibody response to pigeon gammaglobulin (4 micrograms/ml) and were considered to have been sensitised. Increasing exposure was associated with a progressive tendency towards sensitisation, but the intensity of the antibody response was related to the presence of symptoms and not the degree of exposure. Thirteen out of 15 subjects in the survey with a serum concentration of antipigeon IgG greater than 60 micrograms/ml fulfilled the clinical criteria for pigeon breeders' disease, and those affected within 10 years of starting the hobby had the highest mean antibody response. Accurate quantitation of antibody response is therefore helpful in the investigation of pigeon breeders' disease. The radioimmunoassay provides a quantitative method for determining antibody response that can be used in the routine screening of pigeon fanciers and in serial monitoring of their response.

Adult↗
PubMed1985

Alcohol increases cigarette smoking: a laboratory demonstration.

Most people would agree that a relationship exists between drinking alcohol and smoking cigarettes, but there is very little empirical evidence demonstrating a direct causal association. Study of the relationship has been hampered by the lack of a simple laboratory methodology. This article describes an efficient experimental paradigm. Fourteen male narcotic addicts in methadone maintenance treatment volunteered to come to the laboratory for two smoking sessions, during which each subject was given either an alcoholic drink or orange juice, followed by three cigarettes at 20-minute intervals. Drinking alcohol significantly increased the amount and rate of smoking. However, not all subjects reacted to alcohol with increased smoking, and we were unable to account for those individual differences. Our finding supports the theory that a direct causal mechanism linking smoking and drinking exists. That link probably has clinical significance, because there is evidence that ex-smokers are at particularly high risk when they drink alcohol.

Adult↗
PubMed1985

Effect of cigarette smoking on the antibody response to inhaled antigens and the prevalence of extrinsic allergic alveolitis among pigeon breeders.

There was a reduced prevalence of symptoms of Extrinsic Allergic Alveolitis (EAA) among the cigarette smokers in a survey of 102 volunteer pigeon breeders. These smokers had a significantly lower antibody response against the inhaled antigens associated with the disease; only one of twenty-three smokers (4.3%), but thirty-nine of sixty-five non-smokers (55.4%) had elevated serum IgG antibody levels, despite similar degrees of avian exposure in each group. The appearance of antibody in six of fourteen ex-smokers (42.9%) suggested that the apparent inhibitory effect of smoking on the antibody response was reversible. The smoking group had lower total serum IgG and IgA, higher serum IgD, and their total IgM and IgE levels were similar to the nonsmokers.

Alveolitis, Extrinsic Allergic↗