Biomedical subjects
Publications and source records attributed to A Burgess.
Six homosexual men with a diagnosis of acquired immunodeficiency syndrome (AIDS)-related complex (ARC- CDC IVA/C2) were assessed with a series of neuropsychological and psychiatric tests prior to commencing treatment with zidovudine and again after 5-6 months. Significant improvements were seen in cognitive functioning, mental state and physical health at the second assessment.
One approach to the localization of functionally active regions of human granulocyte-macrophage colony-stimulating factor (hGM-CSF) is to map the epitopes recognized by neutralizing anti-hGM-CSF monoclonal antibodies. We have defined the epitope recognized by one neutralizing antibody (LMM102) using proteolytic fragments obtained by enzymic digestion of bacterially synthesized hGM-CSF. RP-HPLC fractionation of a tryptic digest resulted in the identification of an immunoreactive "tryptic core" peptide containing 66 amino acids (52% of the protein). Further digestion of this "tryptic core" with S. aureus V8 protease produced a unique immunoreactive hGM-CSF product comprising two peptides, residues 86-93 and 112-127, linked by a disulfide bond between residues 88 and 121. The individual peptides, generated by reduction with dithiothreitol, were not recognized by the antibody. An analog of this peptide has been synthesized chemically and shown to have similar immunoreactivity to the epitope obtained by enzymic digestion. A series of modified peptides has also been synthesized to identify further the region required for antibody recognition.
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Smears from seven fine-needle aspiration biopsies from three patients with clear-cell sarcoma of the kidney were reviewed, and the findings were correlated with corresponding histopathologic appearances. In two cases, the tumor cells were polygonal to spindle-shaped and were loosely arranged in a matrix of mucoid material. The histopathologic examination of the resected tumors in these cases revealed a classic pattern. In the third case, the aspiration smears revealed round to polygonal cells with moderate to abundant cytoplasm but without the mucoid matrix. The predominant histologic appearance of this tumor was an epithelioid trabecular pattern. Electron microscopic findings were similar to those described in published studies.
We examined the cytomorphologic features of fine-needle aspiration biopsy (FNAB) specimens from 23 Wilms' tumor patients. The findings were correlated with histopathologic patterns from these tumors. The study revealed a close resemblance between the cytologic and histopathologic appearance of various cellular elements in Wilms' tumors. The major cellular patterns seen in Wilms' tumor include blastemal cells, blastemal cells with epithelial differentiation, blastemal cells with tubular differentiation, and stromal elements. It is hoped that recognition of these cellular components in aspiration smears will be helpful in establishing an FNAB diagnosis of Wilms' tumor.
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The necessary duration of antibiotic administration after open fracture has not been established. In a double-blind prospective trial we randomized 248 patients with open fractures to receive one or five days of cefonicid sodium therapy or five days of cefamandole nafate therapy as part of the initial treatment. Rates of fracture-associated infections in the three groups were ten (13%) of 79, ten (12%) of 85, and 11 (13%) of 84, respectively. The 95% confidence limit for the difference in infection rates between the one-day group and the combined five-day groups was 0% to 8.3%. The actual difference was 0.2%. A brief course of antibiotic administration is not inferior to a prolonged course of antibiotics for prevention of postoperative fracture-site infections.
A cheap, portable automated scorer for the Farnsworth-Munsell (FM) 100 hue test has been developed. It consists of a light pen, a series of omni-directional bar-codes attached to the reverse of the FM 100 hue caps and a small micro-computer. The print-out includes patient details, a linear histogram of the partial errors by cap position, indication of the peak error positions for congenital colour vision deficiencies and appropriate statistical analysis of the total error score. All the results are available within four minutes of completing the testing procedure.
There has been recent interest in the synergistic interactions between the growth factors involved in the in vitro control of hematopoiesis and other cell lineages. As a convenient model system, such interactions governing the DNA synthesis in murine bone marrow-derived macrophages (BMMs) were studied. By themselves, murine colony-stimulating factor-1 (CSF-1) and recombinant murine granulocyte-macrophage CSF (GM-CSF) were stimulators of DNA synthesis in quiescent or noncycling BMMs, whereas recombinant murine interleukin-3 (IL-3) and the phorbol ester, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), were weak mitogens. On the other hand, murine granulocyte CSF (G-CSF), concanavalin A (Con A), and lipopolysaccharide (LPS) were inactive on their own. When the quiescent BMMs were exposed to combinations of the CSFs, there were striking synergistic effects for both GM-CSF and IL-3 with suboptimal doses of CSF-1, with a smaller effect for GM-CSF with IL-3 and little or no effect for CSF-1 with G-CSF. CSF-1, GM-CSF, and IL-3 could also synergize with TPA; CSF-1 cooperated with 1-oleoyl-2-acetylglycerol (OAG), both sets of results pointing to an interaction with protein kinase C. LPS completely abolished the CSF-1-mediated stimulation of DNA synthesis. We propose that BMMs are suitable normal cells in which to examine in depth the various mechanistic possibilities for these interactions.
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Scapulothoracic dissociation is a rare entity that consists of disruption of the scapulothoracic articulation. The mechanism of injury is probably traction caused by a blunt force to the shoulder girdle. This lesion is characterized by massive soft-tissue swelling of the shoulder; lateral displacement of the scapula, measured radiographically; an injury to bone (an acromioclavicular separation, a displaced fracture of the clavicle, or a sternoclavicular disruption); a severe neurovascular injury; and a variety of upper and lower-extremity fractures. We treated fifteen patients who had this lesion, most of whom had several associated injuries. Three patients died: two from exsanguination and one from a cardiac arrest. In most patients, the damaged artery was repaired and the brachial plexus was explored. All of the twelve patients who had a complete brachial-plexus injury were left with a flail upper extremity. Most patients refused amputation.
Data inaccuracy due to amplitude quantization in digital imaging systems can be viewed as a form of random noise. The effect of this noise is to reduce the accuracy of decisions based on image data. Experimental results are presented to demonstrate the reduction in human-observer decision accuracy due to quantization noise in addition to white Gaussian noise. There is a significant reduction when the ratio Q/sigma p is greater than unity, where Q is the quantization-step amplitude and sigma p is the standard deviation per pixel of the uncorrelated image noise.
Experimental results are presented demonstrating that humans can make effective use of prior knowledge for detecting and identifying visual signals in static noise. The signals were selected from an orthogonal Hadamard set. There was a marked drop in detection performance when observers did not know which signal was present. The drop was in excellent quantitative agreement with that predicted by the theory of signal detectability. The statistical efficiency of the human observers was 33% in both cases (detection with and without prior knowledge). When interpreted in terms of channel uncertainty, the detection results demonstrated an upper limit of 10 orthogonal, uncertain channels. The statistical efficiency for the Hadamard signal-identification task was 40%. All the results are consistent with the standard theory of signal detectability based on a Bayesian maximum a posteriori probability decision strategy using cross correlation (or matched filtering) of expected signal profiles with those present in the display.
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We present experimental evidence that humans use phase information for detection and discrimination of visual signals (static sine waves) when sufficient a priori information is made available. Under these conditions human performance exceeds that of the best-possible phase-insensitive detector. There is a marked reduction in performance when signal-phase information is not given to the observer.
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Scapulothoracic dissociation, as manifested by lateral displacement of the scapula and acromioclavicular separation, is a previously unreported injury in which there is a complete disruption of the scapulothoracic articulation without an overlying partial or complete amputation through the soft tissue. Associated with the disruption of the scapulothoracic articulation are injuries to the brachial plexus and the subclavian artery and vein; multiple open and closed fractures of the ipsilateral upper extremity are often present also. In the patient with severe multiple injuries, scapulothoracic dissociation may not be recognized immediately, with potentially fatal consequences. In this paper we present the cases of three patients with radiographic and pathological evidence of scapulothoracic dissociation and review the literature on related injuries.