Biomedical subjects
Publications and source records attributed to W H Anderson.
A C-language software program has been developed for emulating the image enhancement processing of a storage phosphor plate system. This software has been implemented on a VAX 3400 computer. There are 2,100 lines of C-language code in the program. There are seven parameters used to specify the degree of enhancement. The software is being implemented on a single accelerator board.
The Department of Labor has set guidelines for the use of resting arterial blood gas analysis in determination of total and permanent disability for coal workers' pneumoconiosis. To determine the prevalence with which bituminous coal miners fall below the arterial tensions of both oxygen and carbon dioxide published in the Federal Register, we studied 1012 miners who had both reproducible spirometry and arterial blood gas analysis as part of their disability evaluation. Eighty-seven percent of impaired miners could be identified by the spirometric criteria. Thirteen percent of impaired bituminous coal miners had acceptable pulmonary function but were eligible for black lung benefits by the blood gas guidelines. This population would have been missed if blood gas analysis were excluded from the evaluation process. On the other hand, approximately 25% of the blood gas analyses that were performed could be eliminated if a policy was adopted to do this test only on miners with spirometry that exceed the federal guidelines.
During the 6-month period from mid February 1988 to mid August 1988, 148 patients presented with 154 diagnosed cases of mandibular third molar pericoronitis. All patients were members of the recruit population stationed at the Recruit Training Command, Great Lakes, Illinois. Selected clinical parameters relating to the orientation and eruption status of these third molars were collected and analyzed. The goal was to obtain a predictive clinical profile of the impacted mandibular third molar (MTM) at greatest risk for pericoronitis in the young naval and Marine Corps personnel. The majority of pericoronitis cases, 120 of 148 or 81.0%, involved vertically oriented MTMs; of this total, 79.1% were erupted to the approximate height of the occlusal plane of the arch. The remaining 20.9% were at or below the height of contour of the adjacent tooth. Mesioangular impacted MTMs accounted for only 11.2% of pericoronitis cases. The remaining cases comprised distoangular and horizontally impacted MTMs (3.4% and 3.8%, respectively). Involvement by impinging maxillary dentition was observed in 39.7% of the vertically oriented MTMs, 56.2% of the mesioangular oriented MTMs, 40.0% of the distoangular MTMs, and 14.0% of the horizontally impacted MTMs. The mean value for occlusal coverage by a soft tissue operculum observed for all MTMs in this study was 49%. In the population studied, risk for pericoronitis appears to increase with greater vertical orientation and height of eruption. The absence of impinging maxillary dentition did not eliminate the risk of mandibular third molar pericoronitis. These data have implications for targeting treatment needs of naval and Marine Corps personnel who may be without dental support for extended periods of time.
We describe a fixation and embedding procedure for the yeast Saccharomyces cerevisiae using Lowicryl HM-20 which is rapid, gives excellent fixation, and avoids the low temperature handling normally associated with embedding in this resin. This procedure yields superior structural preservation when compared to the commonly used rapid embedding procedure which employs Lowicryl K4M. We demonstrate that sections prepared using our rapid procedure are suitable for use in immunogold labelling experiments.
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The severity of insulin-dependent diabetes mellitus had a marked effect upon the development of myocardial sequelae in the rat. Even with the same degree of hyperglycemia, glycosuria, polydipsia, and polyuria, moderately diabetic animals did not develop the degenerative ultrastructural changes seen in myocardium from more severely diabetic rats. These included decreased cardiocyte size, loss and disorganization of myofibrils, and loss of sarcoplasmic reticulum and transverse tubules. Since hyperglycemia and glycosuria are frequently used as the primary, and often sole, criteria for identifying diabetes in experimental animals, this study demonstrates the need to more specifically define the severity of the disease in studies of the heart.
A survey of 150 practicing pulmonary physicians was conducted to determine chemotherapy preferences for the treatment of the patient suffering respiratory insufficiency secondary to active nonmiliary tuberculosis. An equal sample was selected from both the private sector and academic medicine in order to determine if antituberculous agent selection differed between these two groups. The majority of the 109 physicians who responded to the questionnaire (64.2%) indicated that they would use isoniazid, rifampin, and a third agent. There was no statistical difference in the choice of ethambutol, pyrazinamide, or streptomycin as the third drug. There was no difference between university and community based physicians in the use of three drug combinations or in the selection of the specific third agent. This study suggests that, although the majority of pulmonologists responding would treat the patient with respiratory insufficiency from tuberculosis with an aggressive three drug approach, there is no consensus as to which agent should be the third drug.
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The dependence of postmortem blood-drug concentrations on the collection site and on the postmortem interval before specimen collection has been studied. These studies consisted of both sequential sampling from the same collection site at defined time intervals and a comparison of the drug concentrations of postmortem blood simultaneously collected from various sites. A site and time dependence was observed for postmortem blood-drug concentrations. The heart blood-drug concentrations were, in general, significantly higher than those of peripheral specimens. As a result of this phenomenon, the analysis of peripheral blood specimens and solid tissues is often necessary before a definitive interpretation of postmortem toxicological analyses is possible.
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Pleuropulmonary tularemia may mimic atypical pneumonia caused by other common etiologic agents, including Legionella. The correct identification of the pathogen responsible for the atypical pneumonia is usually made serologically or with the use of special stains and cultures. We have reported a case of pleuropulmonary tularemia whose diagnosis was confounded by false-positive direct fluorescent antibody stains for Legionella.
A study was conducted on the use of an irreversible compression technique, Fourier quantization, to reduce the amount of digital data needed for an image. The effect of image compression was studied in radiographs obtained to diagnose subperiosteal bone resorption. Magnification radiographs of 44 hands were digitized to an array size of 4,096 X 4,096 X 12 bits. Selected subregions containing a single middle phalanx were compressed and reconstructed. A subset of the resultant 12-bit uncompressed and 8-, 7-, and 6-bit compressed images were read by four radiologists whose responses were analyzed with receiver operating characteristic (ROC) techniques. There were 81 images used in the ROC analysis, of which 48 were normal and 33 showed subperiosteal resorption. No statistically significant loss of diagnostic quality was detected for 8- or 7-bit compressed images, with average compression ratios of 16:1 and 28:1, respectively. Diagnostic quality was lost with 6-bit images, with an average compression ratio of 107:1.
Gas exchange at rest under normoxic conditions was studied in 2,297 nonsmoking bituminous-coal miners with and without simple coal workers' pneumoconiosis (CWP). Measurements of arterial oxygen tension (Pao2) and arterial carbon dioxide tension (Paco2) from blood gas samples obtained at rest in the seated position were used to calculate the alveolar-arterial oxygen tension difference, (A-a)Do2, using the classic alveolar-air equation. We then recalculated the (A-a)Do2 using the age-predicted Pao2 for each miner. The difference between the actual and the predicted (A-a)Do2 was measured and the mean difference for each category of simple CWP was analyzed. We found no evidence that the resting gas exchange differs significantly from the age-predicted (A-a)Do2 in the nonsmoking bituminous-coal minor with simple CWP. Likewise, there is no significant change in (A-a)Do2 with change in the category of simple CWP.
We studied 82 consecutive patients admitted to the ICU with predominant tricyclic antidepressant overdose (mean plasma tricyclic level, 1,025 ng/ml) to determine the nature and incidence of respiratory complications. The majority of patients (80.4 percent) had a decreased arterial to alveolar oxygen tension ratio (PaO2/PAO2) on initial emergency room arterial blood gas analysis (mean, 0.56). Mechanical ventilation was required in 76.8 percent of the patients for a mean duration of 46.2 h. Chest radiograph abnormalities developed during the first 48 h in 32/82 patients (39 percent). The group with radiographic abnormalities had higher mean drug levels than the group without (p less than 0.05). Of 82 patients, nine (11 percent) developed radiographic evidence of bilateral alveolar infiltrates suggestive of acute lung injury. This group had significantly higher mean drug levels than the groups with other types of radiographic abnormalities (p less than 0.001). Charcoal was recovered from the airway of 18/72 patients who received activated charcoal slurry by nasogastric tube in the emergency room after endotracheal intubation. The group who aspirated did not show statistically significant difference in the incidence of chest radiograph abnormalities, gas exchange, or survival compared with the group that did not aspirate.
The records of 1000 consecutive coal miners applying for benefits under the Federal Coal Mine Health and Safety Act were examined to determine the contribution of age, dust accumulation, and cigarette smoking to the profile of the miner who satisfies the current pulmonary criteria for disability. Using the presence of pneumoconiosis on chest radiograph as the indication of significant coal dust accumulation, the miners were separated into Group A--those without pneumoconiosis (n = 316) and Group B--those with pneumoconiosis (n = 684). The federal spirometric criteria for disability identified 55/316 miners in Group A (14.5%) and 99/684 miners in Group B (17.4%) potentially eligible for an award (P = .27). The mean ages of miners in both groups did not differ significantly, nor was there difference in the mean ages of groups that did or did not meet the federal criteria. In both groups, those miners potentially eligible for a financial award smoked more cigarettes than did their counterparts (Group A, 31.0 v 18.5 pack-years, P less than .001; Group B, 31.3 v 23.6 pack-years, P less than .001). There was no difference in the smoking histories of the miners from either group who met the federal criteria. Our data indicate that, in the case of bituminous coal miners, the present federal legislation intended to identify and remunerate those who suffer lung impairment from chronic occupational exposure to coal dust is biased in favor of those who sustain additional damage to their ventilatory capacity by smoking cigarettes.
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Sonication of lysophosphatidylcholine (lysoPC; 20 mumol/mL) and cholesterol (chol) in aqueous medium produces lamellar structures over a wide range of concentrations. From 25 to 47 mol % cholesterol, electron microscopy (EM) after negative staining showed extended stacklike lamellae about 40 A thick. From 50 to 60 mol % chol, freeze-fracture EM showed homogeneous populations of small unilamellar vesicles averaging 260-310 A in diameter. Phosphorus-31 nuclear magnetic resonance was used to characterize the stacklike lamellae and to measure the distribution of the lysophospholipid between the outer and inner leaflet of the vesicles as a function of sterol concentration. We found that in lysoPC/chol dispersions containing less than equimolar amounts of cholesterol (25-47 mol %), the entire phosphorus signal (40.5 ppm) was shifted downfield by 10.5 ppm upon addition of Pr3+ (2.4 mM), consistent with the stacklike lamellar structures in which all lysoPC head groups are accessible to the ions. By contrast, addition of Pr3+ to lysoPC/chol vesicles containing equimolar or higher amounts of cholesterol (up to 60 mol %) gave rise to two phosphorus peaks. The more intense downfield signal (51.0 ppm) responsive to paramagnetic ions was assigned to lysoPC located in the outer vesicle leaflet. The upfield signal (40.5 ppm), which was not affected by the ions, was assigned to inside lysoPC. For lysoPC/chol (1:1) vesicles, an outside to inside lysophospholipid ratio (Ro/i) of 6.5 was determined. Essentially the same Ro/i value (6.7) was obtained on lysoPC/chol (1:1) vesicles which after dialysis contained only entrapped Pr3+.(ABSTRACT TRUNCATED AT 250 WORDS)