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Biomedical subjects

D W Cugell

Publications and source records attributed to D W Cugell.

At least 19 recordsLinked to original sources
PubMed1992

The hard metal diseases.

Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure.

Alveolitis, Extrinsic Allergic↗
PubMed1991

Serum IgE and IgG to formaldehyde-human serum albumin: lack of relation to gaseous formaldehyde exposure and symptoms.

Fifty-five subjects were studied to determine if the presence of IgE or IgG antibodies to formaldehyde (F)-human serum albumin (HSA) was associated with exposure to gaseous F or with respiratory or conjunctival symptoms from such exposure. The study population included cohorts exposed to F in the workplace, smokers, and normal subjects. IgE antibody specific for F-HSA was detected by ELISA in three subjects; immediate-type skin testing was negative in two of these subjects, and not interpretable because of dermatographism in one subject. One of these subjects had a history of respiratory symptoms when the subject was working in a histology laboratory that contained ambient F and xylene; a respiratory challenge with F at concentrations of up to 2 ppm failed to produce respiratory symptoms or significant changes in pulmonary function. Serum from the three subjects with IgE to F-HSA by ELISA failed to passively transfer skin reactivity to F-HSA to rhesus monkey recipients. These three subjects and two other subjects had IgG to F-HSA by ELISA, although this was of generally low titer. We could not define a relationship between the presence of antibodies and (1) a history of F exposure or (2) a history of adverse respiratory or conjunctival symptoms from F. This study is a continuum of 5 years of study in our laboratory attempting to define allergy to gaseous F, and the current study does not support an immunologic basis for respiratory or conjunctival symptoms from gaseous F exposure. Based on the findings of this and our other studies, it is possible that clinical IgE-mediated allergy to gaseous F does not exist, or if it does exist, it is extremely rare.

Adult↗
PubMed1990

[A respiratory health questionnaire for occupational screening].

A Hebrew pulmonary health questionnaire was designed for occupational screening, based on the American Thoracic Society questionnaire but adjusted to conditions in Israel. It was designed for assisted completion using a computer, but can easily be modified to become self-administered. We propose that it be used here as the standard, occupational, pulmonary health questionnaire and as the basis for a standard, general purpose, respiratory health questionnaire.

Humans↗
PubMed1990

The respiratory effects of cobalt.

We studied seven subjects with certain manifestations of cobalt-induced lung disease. All worked with cobalt and were involved in either the production or use of hard metal. The mode of presentation varied from an acute hypersensitivity pneumonitis that cleared completely when exposure ceased to progressive severe interstitial fibrosis of the lungs. In one subject reexposure was followed by a recurrence of the symptoms. All subjects showed restrictive ventilatory impairment and a reduction of their diffusing capacity. The radiologic appearances varied greatly. While two subjects had clear roentgenograms with small lung volumes, others had a micronodular pattern or small blotchy nodular infiltrates, and one had diffuse reticulonodulation as is seen in cryptogenic fibrosing alveolitis. The pathologic appearances varied between desquamative interstitial pneumonia and overt mural fibrosis of the alveoli. Six of the seven patients had multinucleated giant cells in their biopsy specimens or bronchoalveolar lavage fluid.

Adult↗
PubMed1989

Wideband acoustic transmission of human lungs.

The measurement of sound transmission in human lungs has shown promise to reveal, by noninvasive methods, information about the structure of peripheral airways and lung tissue. The paper gives a detailed explanation of the instrumentation and testing methods developed to measure sound transmission through human lungs and thoracic structures in the 5-20 kHz frequency range and describes in detail experiments comparing the acoustic lung transmission patterns of four different subject groups. The experimental results are compared with those predicted by an acoustical model of sound transmission through lung parenchyma.

Acoustics↗
PubMed1989

Flutter in flow-limited collapsible tubes: a mechanism for generation of wheezes.

We studied flutter in collapsible tubes as a possible mechanism for the generation of respiratory wheezes. The pressure-flow relationships and the wall oscillations of thick-walled [wall thickness (h)-to-lumen radius (r) ratio 1:1.7 to 1.3] self-supporting latex and Silastic tubes mounted between rigid pipes were measured. A high-impedance vacuum pump was connected to the downstream end. Upstream and downstream valves were used to control corresponding resistances. We found loud honking sounds and tube wall oscillations that occurred only when the tubes were buckled and flow limiting, i.e., when the flow became constant and independent of downstream driving pressure. The overall range of oscillatory frequencies was 260-750 Hz for airflow, presenting as sharp peaks of power on the frequency spectrum. The oscillatory frequencies (f) were higher at higher fluid velocities (u) and with narrower distance between opposing flattened walls (2b), resulting from increasing downstream suction pressure and the transmural pressure becoming more negative. The effect of u and b on f for a latex tube (h-to-r ratio 1:1.7) were found to be f = 228 + 0.021 (u/b). These relationships were valid throughout the range of oscillations in this tube (283-720 Hz) and with flow rates of 12-64 l/min. The experimental data were compared with predictions of the fluid dynamic flutter theory and the vortex-induced wall vibrations mechanism. We conclude that viscid flutter in soft tubes is the more probable mechanism for the generation of oscillations in the soft tube model and is a possible mechanism for the generation of respiratory wheezes.

Humans↗
PubMed1988

The effect of gravity on the response of ventilation to abrupt change in FICO2.

Recently, Arieli and Farhi (1987) formulated a model for a previous suggestion made by their group that an increased ventilation as gravity increases is due to reduced perfusion of the respiratory center which causes an elevation of tissue PCO2. Extending the model to the dynamic response, we predict a slower ventilatory response to CO2 breathing as gravity increases. To test this prediction, ventilatory response to 5% CO2 was studied in 11 seated subjects at +1 and +2 Gz in a human centrifuge. Five of these subjects were studied at +3 Gz as well. In addition, ventilatory response to 5% CO2, using breath-by-breath analysis, was measured in three subjects in supine and upright postures. The ventilatory response (mainly through tidal volume) was faster as gravity increased from +1 to +2 and to +3 Gz, and from supine to the upright position. These findings disagree with the model prediction. Therefore, an alternative explanation is suggested based on the response of CO2 sensitive stretch receptors in the lung. Increased gravity causes increased ventilation, reduction of cardiac output and increased VA/Q mismatch; all enlarge the part of the lung with low CO2 where responsiveness of the CO2 sensitive stretch receptors is large.

Adult↗
PubMed1987

Changes on radiographs of wives of workers exposed to asbestos.

Between January and March 1986, 117 wives of insulation workers exposed to asbestos were screened by means of chest radiography, pulmonary function testing, and a detailed questionnaire. The final study group included 93 women over 40 years of age. Eighteen of these (19.4%) demonstrated pleural changes consistent with asbestos exposure, including pleural plaque (88.9%), diaphragm plaque (27.8%), pleural calcification (16.6%), and diffuse pleural thickening (5.5%). In statistical correlation between the groups with normal and abnormal radiographs, the only factor that proved significant was the year of first exposure (the duration of the latent period). Finally, radiographs of the husbands were compared for 17 of the 18 wives with radiographic abnormalities. Fourteen of the husbands (82%) demonstrated more severe radiographic changes than their wives.

Adult↗
PubMed1986

Clinical pharmacology and toxicology of ipratropium bromide.

Anticholinergic drugs inhibit a variety of intrapulmonary events related to airflow obstruction. When administered as an inhaled aerosol, approximately 90 percent of ipratropium bromide (as with beta-adrenergic aerosols) can be assumed to be swallowed. Peak pharmacologic effects occur prior to any detectable plasma drug concentrations. Ipratropium does not exhibit the well-known toxic effects of atropine, and doses many times those required for maximum therapeutic benefit do not produce any effects on the eye, urinary bladder, heart rate, or mucociliary function. Ipratropium seems to act primarily on large- and intermediate-size airways; beta-adrenergic agents, on the other hand, appear to act primarily on the smaller airways. The drug is a promising addition to the therapeutic armamentarium, and may be especially useful in certain groups of patients whose condition is less responsive to other agents.

Aerosols↗
PubMed1986

Comparison of the anticholinergic bronchodilator ipratropium bromide with metaproterenol in chronic obstructive pulmonary disease. A 90-day multi-center study.

The short- and long-term efficacy and safety of an inhaled quaternary ammonium anticholinergic agent, ipratropium bromide, and a beta agonist aerosol, metaproterenol, were compared in 261 nonatopic patients with chronic obstructive pulmonary disease (COPD). The study was a randomized, double-blind, 90-day, parallel-group trial. On three test days-one, 45, and 90-mean peak responses for forced expiratory volume in one second and forced vital capacity and mean area under the time-response curve were higher for ipratropium than for metaproterenol. Clinical improvement was noted in both treatment groups, especially during the first treatment month, with persistence of improvement throughout the remainder of the study. Side effects were relatively infrequent and generally mild; tremor, a complication of beta agonists, was not reported by any subject receiving ipratropium. These results support the effectiveness and safety of long-term treatment with inhaled ipratropium in COPD.

Adult↗
PubMed1979

Selection of patients with hemoptysis for fiberoptic bronchoscopy.

One hundred ten hospitalized patients with hemoptysis were reviewed to identify factors that would characterize those with malignancy and to evaluate the usefulness of fiberoptic bronchoscopy (FB) in the diagnosis of hemoptysis. Seventy patients underwent FB. This procedure was diagnostic in 22/28 (79 percent) of the carcinoma patients and in 26/42 (62 percent) of the patients with a nonmalignant cause of hemoptysis. The following three characteristics indicate a high probability of malignancy: 1) age greater than 40 years, 2) any abnormality on the chest roentgenogram, 3) hemoptysis lasting greater than one week. If any of these factors are present, FB should be done. Other factors to be considered include presence of anemia, weight loss, persistent cough, long smoking history and risk of bronchoscopic complications.

Adult↗
PubMed1979

The radiologic significance of the left pulmonary ligament. Experience with 26 patients.

Pathologic processes confined to or by the left pulmonary ligament present a confusing radiographic appearance. Such processes may simulate pleural scarring, parenchymal scarring, or even left lower lobe collapse. Radiologic awareness of this structure is limited because in the normal state, it is not visualized on either posteroanterior or lateral chest x-ray films. The absence of secondary signs of left lower lobe collapse, together with a process which may extend above the level of the left hilum, is valuable in confirming that such a triangular density seen behind the left cardiac border is disease in or confined by the pulmonary ligament, rather than left lower lobe collapse.

Adult↗