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Biomedical subjects

A B Thompson

Publications and source records attributed to A B Thompson.

At least 73 records · Page 4Linked to original sources
PubMed1988

Mechanisms of neutrophil recruitment to the lung by grain dust exposure.

Inhalation of grain dusts can cause symptoms of both acute and chronic bronchitis, which has been associated with a neutrophilic inflammatory response in the lung. Since this influx of neutrophils may potentially result in bronchial injury, mechanisms of neutrophil recruitment to grain dust were examined. Sterile, aqueous grain dust extracts were prepared from settled dusts of grain sorghum, corn, oats, and soybeans. The extracts were evaluated for their ability to directly attract human neutrophils using a blindwell neutrophil chemotaxis assay. Each extract was found to possess significant chemotactic activity compared to control (p less than 0.01). To evaluate if the dusts could attract neutrophils indirectly by activating humoral inflammatory mechanisms, the grain dust extracts were evaluated for their ability to activate the complement system. When incubated with normal human serum, each of the grain dusts caused cleavage of the complement proteins C3 and properdin factor B (PFB). Importantly, the grain dust extracts lead to the generation of C5a, a potent neutrophil chemoattractant generated by complement activation. Since activation of the alveolar macrophage to release chemotactic activity represents an additional indirect mechanism of neutrophil recruitment, an extract from grain sorghum dust was evaluated for its ability to stimulate guinea pig and human alveolar macrophages to release neutrophil chemotactic activity. The results demonstrate that supernatants obtained from alveolar macrophages cultured in the presence of grain sorghum dust extract possessed increased chemotactic activity compared to controls (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗
PubMed1988

Assessment of airways inflammation utilizing bronchoalveolar lavage.

Pathologic correlations and examination of expectorated sputum have suggested that chronic bronchitis is an inflammatory disorder of the airways. Bronchoscopy and bronchoalveolar lavage provide a means for sampling airway epithelial lining fluid. Application of bronchoscopy and bronchoalveolar lavage to a group of patients with chronic bronchitis confirms the association of airways inflammation and chronic bronchitis.

Bronchitis↗
PubMed1985

Nd:YAG laser followed by radiation for treatment of malignant airway lesions.

Patients with malignant obstructive airway lesions often present with total or segmental atelectasis of lung. In spite of prompt initiation of palliative external radiation alone, some patients were unable to complete the planned course of radiation therapy. Since May 1983, 17 patients with malignant obstructive endobronchial lesions have been treated by endoscopic Nd:YAG laser vaporization of the tumor. One to seven days later, fractionated external radiation therapy was initiated. Endoscopic use of the laser was repeated as needed during the course of treatment. Fifteen out of 17 patients successfully completed the planned course of therapy. The improved performance status was sustained in 13 of 15 patients for 2-13 months. A control group was selected from among patients with similarly located lesions who underwent external radiation treatment only prior to the availability of the Nd:YAG laser therapy. One patient developed radiation pneumonitis six weeks after completion of a second course of external radiation, another patient developed bronchopleural fistula after laser treatment which healed following closed chest tube drainage. The others had longer palliation of symptoms and improved quality of life. The results indicate that relief of airway obstruction by use of the Nd:YAG laser improved the patients' ability to tolerate subsequent external radiation treatment.

Bronchial Neoplasms↗
PubMed1985

Profilicollis botulus (Acanthocephala) abundance in the eider duck (Somateria mollissima) on the Ythan estuary, Aberdeenshire.

The abundance of Profilicollis botulus was monitored in eider ducks for 3 years. No significant difference in P. botulus abundance was found between eiders taken alive and those collected dead from the shore line, or between adult males and adult females. Adult male eiders had a seasonal pattern of infection. Incubating female eiders lost their infection in almost all cases, suggesting that a seasonal pattern of infection must also occur in these birds. Eiders in their first winter had P. botulus abundances which were approximately 10 times that of adult eiders, but by the following summer the abundance had declined to that found in adults. Data are compared with previous studies undertaken on the Ythan estuary. Captive eiders were used to determine the developmental rate of female P. botulus and the percentage of administered cystacanths which established in the intestine. There was no evidence to suggest that male and female P. botulus have different life-spans.

Acanthocephala↗
PubMed1985

Endoscopic laser therapy for respiratory distress due to obstructive airway tumors.

Neodymium-YAG laser therapy for unresectable malignant airway obstructions has a promising future. Nine patients with moderate to severe respiratory distress all experienced rapid relief of dyspnea and substantial improvement in pulmonary function within hours to days after treatment with laser phototherapy. The quality of life and survival was improved in otherwise hopeless cases. A nonfatal case of pneumothorax was the only major complication.

Adult↗
PubMed1976

Duodenal contraction wave patterns in patients with and without ulcer.

To determine whether differences in frequency of specific wave sequences and types existed in the four parts of the duodenum in ulcer subjects and controls an analysis of contraction waves in 14 controls and 10 duodenal ulcer patients of similar age was done by a statistical analysis of differences between the two groups. A water-perfused tube system was used. Differences in motor activity, namely, decreased frequency of waves in the proximal duodenum and increased frequency of waves in the distal duodenum in ulcer subjects as compared to controls was demonstrated. This involved a statistically significant decrease in numbers of mixing (or basic rhythm) waves in the proximal duodenum. Increased numbers of isolated waves were found in ulcer patients in the distal duodenum. The predominant types of contraction waves in both ulcer and control subjects were isolated and simultaneous waves, with peristaltic waves were less common in the fasting state. These findings suggest that differences exist in the types of contraction waves in duodenal ulcer subjects compared to controls.

Duodenal Ulcer↗
PubMedDate not supplied

In vivo and in vitro methods for evaluating airways inflammation: implications for respiratory toxicology.

The lung is frequently the target of injury for toxic exposures. Often these exposures lead to significant disease. Assessment of toxic exposures to the lung, however, may be made using both in vitro and in vivo methods. Recent advances in respiratory cell biology have made possible in vitro analyses of the interactions between airway cells and potential toxins. In addition, the lung can be sampled in vivo using bronchoscopy and bronchoalveolar lavage. This opens up the possibility of assessing potential toxins prior to the development of clinically significant disease. Together, these advancing methodologies promise new potential for the assessment and evaluation of toxic exposures to the lung.

Air Pollutants↗
PubMedDate not supplied

Diagnostic imaging of breast cancer using fluorescence-enhanced optical tomography: phantom studies.

Molecular targeting with exogenous near-infrared excitable fluorescent agents using time-dependent imaging techniques may enable diagnostic imaging of breast cancer and prognostic imaging of sentinel lymph nodes within the breast. However, prior to the administration of unproven contrast agents, phantom studies on clinically relevant volumes are essential to assess the benefits of fluorescence-enhanced optical imaging in humans. Diagnostic 3-D fluorescence-enhanced optical tomography is demonstrated using 0.5 to 1 cm(3) single and multiple targets differentiated from their surroundings by indocyanine green (micromolar) in a breast-shaped phantom (10-cm diameter). Fluorescence measurements of referenced ac intensity and phase shift were acquired in response to point illumination measurement geometry using a homodyned intensified charge-coupled device system modulated at 100 MHz. Bayesian reconstructions show artifact-free 3-D images (3857 unknowns) from 3-D boundary surface measurements (126 to 439). In a reflectance geometry appropriate for prognostic imaging of lymph node involvement, fluorescence measurements were likewise acquired from the surface of a semi-infinite phantom (8x8x8 cm(3)) in response to area illumination (12 cm(2)) by excitation light. Tomographic 3-D reconstructions (24,123 unknowns) were recovered from 2-D boundary surface measurements (3194) using the modified truncated Newton's method. These studies represent the first 3-D tomographic images from physiologically relevant geometries for breast imaging.

Algorithms↗
PubMedDate not supplied

[Effects of transdermal nicotine as an adjunct in smoking cessation therapy. A double-blind randomized study controlled with placebo].

To assess the smoking cessation efficacy of transdermal nicotine patches an adjunct to low-intervention therapy, we conducted a double-blind, placebo-controlled trial in 158 smokers. Participants were randomly assigned to one of the following three study regimens that required daily application of two 15-cm2 patches: 1) 24-hour nicotine delivery, 2) nicotine delivery during wakeful hours only, and 3) placebo. The impact of the three regimens on smoking cessation rates and tobacco withdrawal symptoms was examined. During the last 2 weeks of the trial, 39% of the 24-hour nicotine regimen delivery group, 35% of those on wakeful hour nicotine regimens, and 13.5% of the placebo treatment group achieved abstinence. Self-reported quit rates for the two nicotine patch-wearing regimens, as compared with that for the placebo group, continued to be significantly higher at 6 months. Moreover, compared with placebo, the transdermal nicotine patches significantly reduced tobacco withdrawal symptoms during the first few weeks of quitting. The differences in quit rates and tobacco withdrawal symptoms between the to active groups were not statistically significant. The patches were well tolerated both topically and systemically. We concluded that transdermal nicotine, when used as an adjunct to low-intervention therapy, significantly reduced tobacco withdrawal symptoms and enhanced smoking cessation rates.

Administration, Cutaneous↗