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Biomedical subjects

D Morris

Publications and source records attributed to D Morris.

At least 163 records · Page 9Linked to original sources
PubMed1988

Mycobacterium bovis as an occupational hazard in abattoir workers.

Five cases of bovine tuberculosis occurred in a two year period in South Australia, which represents a higher incidence than in previous years. All five patients had a history of employment in an abattoir (although four different abattoirs were involved) and four of the cases had pulmonary or pleural TB. A voluntary survey of one of the abattoirs was conducted which discovered the fifth case of active pulmonary TB. We suggest that bovine TB should be considered an occupational hazard in abattoir workers, and that suitable pre-employment screening programmes for workers be established. The transmission of disease in these cases is almost certainly by inhalation causing pulmonary TB and is therefore different from the 'classic' form of bovine TB transmitted by ingestion of infected milk and resulting in extrapulmonary disease.

Abattoirs↗
PubMed1988

Quantitative analysis of the tomographic thallium-201 myocardial bullseye display: critical role of correcting for patient motion.

Single photon emission computed tomography (SPECT) myocardial 201TI imaging appears to offer major improvements over planar imaging. Quantitative analysis of the 201TI images appears to offer major advantages over subjective analysis in planar imaging, but the three-dimensional data available in SPECT images requires special approaches to analysis and display. Thus the myocardial "bullseye" display was developed to summarize and analyze the three-dimensional images of the left ventricle in two dimensions. The relative 201TI distribution to each region of the left ventricle of an individual patient can be displayed as the number of s.d.s away from normal that the region falls. We found that patient motion during the 22 min required for SPECT imaging appeared to produce artifactual defects. Thus, computer programs were developed to quantitate motion between consecutive frames of a [201TI] SPECT myocardial imaging study, simulate nonreturning vertical motion in normal patients, and correct the acquired data for motion. Motion as small as 0.5-1.0 pixel (3-6 mm) in the vertical (axial) direction caused artifactual defects in the quantitative bullseye display that resulted in a false-positive rate of up to 40% for a +1.0 pixel shift. Patient motion of magnitude greater than the threshold value for artifact-production (0.5 pixel) occurred at a rate of 10%, and should be corrected before tomographic reconstruction.

Heart↗
PubMed1987

Effects of wound exudates on in vitro immune parameters.

Although local failure of antibacterial host defenses in the surgical wound may contribute to the development of wound infections, little attention has been focused on this problem. The goals of the current study were to determine the biological activity of postsurgical wound exudates (seroma fluids) on normal neutrophil and lymphocyte function and to quantitate the levels of complement and plasma fibronectin in these wound exudates. The wound exudates did not support the opsonophagocytosis and killing of Staphylococcus aureus or Pseudomonas aeruginosa by control neutrophils as well as serum (P less than 0.01) and was inferior to serum as a neutrophil chemoattractant (P less than 0.01). Similarly, the wound exudates did not support mitogen-induced lymphocyte blastogenesis as well as normal serum (P less than 0.01). The impaired function of both neutrophils and lymphocytes incubated in the wound exudates appeared to be due to a lack of normal humoral factors, rather than to the presence of inhibitory factors, since the addition of normal serum to the wound exudates restored cellular activity to normal. The findings of decreased levels of plasma fibronectin and decreased complement hemolytic activity in the wound exudates were consistent with the concept of a local deficiency of immune-related humoral factors. Thus, this study supports the clinical concept that local collections of wound fluids may predispose to wound infections by hampering effective local host defenses.

Adult↗
PubMed1987

Opiate addiction and plasma beta-endorphin-like immunoreactivity: methadone maintained, recently detoxified and early naltrexone treated ex-addicts.

Plasma beta-endorphin-like radioimmunoreactivity (BEND) was measured in opiate addicts and controls with an antisera which cross reacted with lipotropin but not with other endogenous opiate peptides. 43 stable male methadone maintained patients had mean BEND of 18 +/- 11 pg/ml. No relationship was found between BEND, and time of day, dose or time since last methadone. Controls had 22 +/- 8pg/ml. 9 hospitalized freshly detoxified male opiate addicts, 7-23 days after last opioid, had BEND of 32 +/- 11 pg/ml. These same took 7 days of 50 mg oral naltrexone (NTX) daily, and repeat BEND was 41 +/- 13 pg/ml, rising in all instances compared to baseline. Ex-addicts after detoxification had high BEND which rose further during a short course of NTX. Methadone maintained patients had normal BEND. These data are consistent with previous animal and human reports of high plasma BEND level with NTX or detoxification.

Adult↗
PubMed1987

Risk of developing complete heart block during bedside pulmonary artery catheterization in patients with left bundle-branch block.

We examined the incidence of complete heart block (CHB) as a complication of pulmonary artery catheterization with balloon-tipped, flow-directed catheters in patients with left bundle-branch block (LBBB). The study group included 47 consecutive critically ill patients with LBBB in the medical intensive care and coronary care units, who underwent a total of 82 pulmonary artery catheterizations. Twenty-six patients had an acute myocardial infarction, 34 patients had severe congestive heart failure (Killip class III or class IV), and 15 patients died during their hospitalization. Thirty patients had an old LBBB (more than one month in age), nine patients had a new LBBB, and the age of the LBBB was indeterminate in eight patients. There were five episodes of CHB in the group of patients with old LBBB. However, none of these episodes were related to the pulmonary artery catheterization, since CHB occurred either prior to catheterization (one case) or from one to 16 days after the pulmonary artery catheter had been removed (four cases). There were no episodes of CHB related to the pulmonary artery catheterization procedure in the patients with either old LBBB or indeterminate-aged LBBB. There were two episodes of CHB in patients with new LBBB. In both patients, the CHB occurred one day after the pulmonary artery catheter had been inserted. In both patients, CHB developed after episodes of ventricular tachycardia that eventually resulted in their deaths. Although it is unlikely, we could not rule out the possibility that the CHB was related to the presence of the pulmonary artery catheter. We conclude that the incidence of CHB complicating pulmonary artery catheterization with balloon-tipped, flow-directed catheters in critically ill patients with old or indeterminate-aged LBBB is extremely low. Therefore, we do not recommend the routine placement of a temporary transvenous pacemaker in all patients with LBBB prior to pulmonary artery catheterization.

Aged↗
PubMed1986

A model for assessing the sensitivity and specificity of tests subject to selection bias. Application to exercise radionuclide ventriculography for diagnosis of coronary artery disease.

A probabilistic model was developed which allows one to estimate sensitivity and specificity of diagnostic tests for coronary artery disease without reference to angiography. The feasibility of the model was evaluated first in a series of computer simulations, and the model was then applied to the assessment of ejection fraction in 933 patients without prior myocardial infarction who underwent exercise radionuclide ventriculography. In 196 patients who were referred to angiography, the conventional abnormal ejection fraction criterion--an absolute rise of less than 0.05 with exercise--had a sensitivity of 79% and a specificity of 68% when referenced to coronary angiography. In 737 patients who were not referred for angiography and who were analyzed instead by our probabilistic model, sensitivity was 63% (p = 0.004 compared to that in the 119 angiographically diseases patients) and specificity was 79% (p = 0.036 compared to that in the 77 angiographic normals). Both the higher sensitivity and lower specificity in the catheterized patients are consistent with a preferential referral of positive test responders to angiography, and of negative test responders away from angiography. The distortion of test sensitivity and specificity which results from this selection bias can be circumvented by substituting a probabilistic estimate of disease for conventional angiographic ascertainment.

Adult↗
PubMed1986

Electrical treatment of Lewis lung carcinoma in mice.

Direct electrical current of sufficient magnitude and duration can destroy tissue. This capability may be clinically useful in some cases involving inoperable metastatic lesions. In principle, a tumor could be treated with direct current administered via a percutaneous electrode insulated along its entire length except for the portion actually inserted into the tumor. An animal model was developed to study the effect of direct electrical current on tumor growth. The growth of implanted Lewis lung carcinoma in mice was inhibited following the administration of 2 mA for 1 hr, 1-3 treatments. The effect occurred in both small and large tumors. The results suggest that the electrical technique is potentially useful for treating some tumors.

Animals↗
PubMed1986

Should the intent of testing influence its interpretation?

A test is often interpreted as "normal" or "abnormal" by a single criterion, regardless of the intent of testing. The discriminate accuracy of this convention was critically analyzed using information content (I), likelihood ratio and the area under the receiver-operating characteristic curve. Three ejection fraction variables were assessed--ejection fraction at rest, exercise ejection fraction and the change in ejection fraction from rest to exercise--each relative to three intentional goals: diagnosis of coronary artery disease in 929 patients without previous myocardial infarction, prediction of multivessel disease in these same 929 patients and prediction of multivessel disease in 507 patients with previous myocardial infarction. The information content of exercise ejection fraction (IEX) was higher than for ejection fraction at rest (IR) or for the change from rest to exercise (IEX-R), and was relatively constant regardless of the goal of testing. In contrast, neither IR nor IEX-R was constant. IR was lowest for diagnosis of coronary artery disease, whereas IEX-R was highest for this same goal. These empiric observations are consistent with the quantitative relation predicted by information theory: IEX = IR + IEX-R. Thus, ejection fraction at rest has little discriminate value relative to the diagnosis of coronary artery disease, but does have value in evaluating the extent of disease in patients after myocardial infarction. Exercise ejection fraction and change in ejection fraction are nearly equally useful for purposes of diagnosis, whereas the former is most useful for functional evaluation in postinfarction patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗