Biomedical subjects
K A Bell
Publications and source records attributed to K A Bell.
Growth rate measurements and deposition modelling of hygroscopic aerosols in human tracheobronchial models.
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Computed tomography of deep cerebral venous thrombosis in children.
Three cases of deep cerebral venous thrombosis in children are presented, and the cranial computed tomographic (CT) findings and angiographic findings reviewed. Two patients had findings indicative of brain death at the time of initial CT examination. The third patient recovered without neurological sequelae. Noncontrast-enhanced CT examinations showed abnormally dense-appearing deep venous structures, mimicking a contrast-enhanced study. On the arteriogram the deep venous system failed to opacify, and multiple collaterals to the superficial venous system were formed.
Sulfate aerosol generation and characterization for controlled human exposures.
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Aneurysm of popliteal artery after medial meniscectomy: an unusual complication.
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Angiodysplasia of the colon.
Angiodysplasia of the colon was diagnosed by arteriography in 33 patients. Approximately one fourth of the lesions were located in the left side of the colon. Three patients with sigmoid lesions had a second lesion elsewhere in the gastrointestinal tract. The lesions on the left involved a more extensive segment of bowel than those on the right. Almost one third of the patients were younger than 60, and 2 were in their thirties. The angiodysplasia is the source of the bleeding in most patients, and its resection results in cure.
Controlled exposures of human volunteers to sulfate aerosols. Health effects and aerosol characterization.
Our laboratory has undertaken the study of possible acute adverse health effects of sulfate aerosols through controlled exposures of volunteer human subjects. Both healthy and asthmatic adult men were exposed for 2-hour periods (with intermittent exercise) to ammonium sulfate, ammonium bisulfate, and sulfuric acid of particle size distributions and concentrations intended to simulate "worst case" exposures during Los Angeles smog episodes. Lung function tests were performed by the subjects on entering and before exiting from a carefully controlled environmental chamber. Subject symptoms were evluated in a standardized manner. Aerosol concentrations and size distributions were determined by an on-line computer/aerometric monitoring system; gravimetric and chemical analyses were performed on impactor and total filter samples after test exposures. We found little or no evidence of adverse health effects from 2-hour multiple-day exposures to any of the compounds at "worst case" ambient concentrations.
Chylothorax and lymphangiomas of bone: unusual manifestations of lymphatic disease.
A patient with chylothorax, mediastinal lymphangiomatous malformation of the thoracic duct, and multiple lymphangiomas of bone is reported. If a patient has radiographic findings of increased pleural fluid with multiple lucent lesions of the skeleton, the possibility of a generalized abnormality in the lymphatic system should be considered. Early diagnosis and treatment can prevent a protracted course and wasting of the body due to the loss of essential body nutrients in the chylous fluid.
Respiratory effects of exposure to ozone plus sulfur dioxide in Southern Californians and Eastern Canadians.
Volunteer subjects were exposed in an environmentally controlled chamber in Los Angeles to SO2 and O3, separately and in combination, to study the enhanced toxicity of the O3 + SO2 mixture observed in a previous study in Montreal. Toxic responses to O3 + SO2 were less severe than observed previously, and only slightly more severe than with O3 alone. Sulfur-containing aerosols formed by chemical reactions within the chamber air may have contributed to the O3 + SO2 responses in the Montreal study. Adaptation of Los Angeles residents to ambient O3 may also contribute to response variability.
The added gradient echo pulse sequence technique: application to imaging of fluid in the temporomandibular joint.
PURPOSE: To assess the value of an added gradient echo in the same pulse sequence with a T1-weighted spin echo for determining the presence of an abnormal fluid collection in the temporomandibular joint with no additional imaging time. MATERIALS AND METHODS: Using a standard T1-weighted sequence used in cine temporomandibular joint imaging, a readout gradient reversal was added and the resulting gradient echo collected. This image was compared with standard T1- and T2-weighted sequences, a short inversion recovery imaging sequence, and a small flip angle fast low-angle shot gradient-echo sequence. RESULTS: The T1-weighted spin echo preceding the added gradient echo is not affected by the gradient reversal, but the additional gradient echo adds T2* contrast information that displays fluid as bright as and compares favorably with other fluid detection sequences. CONCLUSION: The added gradient-echo technique adds sensitivity for the detection of an abnormal increase in fluid in the temporomandibular joint without adding to the overall imaging time of a routine T1-weighted sequence.