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Biomedical subjects

D D O'Sullivan

Publications and source records attributed to D D O'Sullivan.

At least 19 recordsLinked to original sources
PubMed1991

Bronchial mucus hypersecretion in acute quadriplegia. Macromolecular yields and glycoconjugate composition.

In acute quadriplegia we have noted that about one in five patients develops unexplained production of markedly excessive and tenacious bronchial mucus. Spontaneous recovery from mucus hypersecretion usually occurs within weeks to months. Mucus samples collected from 12 patients have been found to be abnormal. Macromolecular contents of single aspirates yielded as much as 500 mg. Analytical ultracentrifuge analysis showed the mucus to contain considerable epithelial glycoprotein (GP) of typical buoyant density; its amino acid and carbohydrate compositions were characteristic of the GP from hypersecretory bronchial mucus such as in chronic bronchitis and cystic fibrosis. In five patients studied after recovery from hypersecretion, there tended to be relatively less GP. The mucus samples contained a high density glycoconjugate (GC): this had sugars of GP but also reacted positively with a monoclonal antibody to keratan sulfate. Its amino acid composition was different from that of GP: threonine was lower and glycine was higher than in GP. In mucus from one patient who died, chondroitin sulfate ABC and hyaluronic acid were identified as well. This suggests proteoglycans are involved in the pathophysiology of mucus hypersecretion. The sudden onset and spontaneous recovery of hypersecretion suggests that it is not due to gland hypertrophy. We speculate that in acute quadriplegia it is due to disturbed neuronal control of bronchial mucus gland secretion, perhaps related to initial disappearance and later reappearance of peripheral sympathetic nervous system tone.

Acute Disease↗
PubMed1991

Defining the proper attribution of responsibility for quality of care.

The term "medical care" is frequently used when either "health care" or "patient care" would be more accurate. This inaccurate use of terminology not only fosters the impression that physicians have sole responsibility for the entire health care system, but also hinders efforts to place properly the actual responsibility for the quality of care. This article proposes three precise definitions, based on the unique features that distinguish health care, patient care, and medical care, which emphasize the characteristics of each domain. Proper use of these definitions can prevent the confusion of one area of care with another, and should ultimately result in the quality of each area becoming better defined, and thereby better controlled.

Health Facilities↗
PubMed1989

Organizational control of hospital infrastructure determines the quality of care.

Hospital personnel and their performance underlie all hospital facilities and patient services (the hospital infrastructure). Hence, quality patient care is not exclusively in the domain of the medical staff and must be regarded as a comprehensive responsibility of the hospital. Hospitals must establish behavioral quality systems and teach employees not only how to do their job well to meet technical quality standards, but also how to fulfill patient expectations. Critical and life threatening problems are thereon prevented or minimized, and protection of physicians and hospitals from litigation improves as a result. Governing boards must provide a role model and demand excellence of everyone, in order to improve the performance of the hospital infrastructure.

Attitude of Health Personnel↗
PubMed1989

The hospital infrastructure: the key to quality patient care.

The quality of patient care depends on the strength of a hospital's infrastructure. In this article, the author discusses ways to strengthen the hospital infrastructure and thereby improve the hospital environment and the quality of hospital services.

Consumer Behavior↗
PubMed1988

Characterization of airway mucus from a fatal case of status asthmaticus.

We used density gradient methods to analyze mucus recovered from the airways of a patient who died from status asthmaticus. At postmortem the mucus that plugged the length of the bronchial tree could only be removed by cutting with forceps. It was dispersed in cesium bromide (CsBr) and examined in the analytical ultracentrifuge. Surprisingly, no macromolecular component was seen in the buoyant density region typical of mucus glycoprotein (at 1.5 g/ml). The gelatinous material migrated to the region of lowest density, typical of lipids, and thin-layer chromatography indicated that besides neutral lipids, a variety of phospho- and glycolipids (including gangliosides) were present. The residue left after the lipid extraction contained all sugar components of mucus glycoprotein, and alkaline borohydride cleaved oligosaccharides three to 12 sugars long, indicating that the sugars were O-glycosidically linked as in mucus glycoproteins. Prior desulfation of the residue increased the number of oligosaccharides released by borohydride; analysis showed the presence in these of components (glucose, methylmannuronate) not present in epithelial glycoprotein. A trace component of high buoyant density was also present: Glucose was the predominant component in this, but glycoprotein sugars were also present. The above results suggest that in status asthmaticus plugging of the airways with mucus can occur even in the absence of typical epithelial glycoprotein and that lipids play a crucial role in such plugging.

Adolescent↗
PubMed1988

Transition from normal to hypersecretory bronchial mucus in a canine model of bronchitis: changes in yield and composition.

Density-gradient analysis was used to follow the transition from normal to hypersecretory bronchial mucus in a model of bronchitis induced in dogs by chronic exposure to SO2 gas. Aspirates of saline bronchial lavage were obtained by fiberoptic bronchoscopy from dogs before, during a 6- to 9-month exposure period to SO2 gas, and during a recovery period of similar duration. Prior to SO2 exposure, aspirates from all animals had a low yield of nondialyzable macromolecules (15 +/- 6 mg/aspirate) and similar composition. Specifically, epithelial glycoprotein of typical buoyant density was not detected; rather a glycoconjugate of higher buoyant density with features of both proteoglycan and glycoprotein was identified. Neutral lipids were predominant with lesser amounts of phospholipids; no glycolipids were detected. During the SO2 exposure period, aspirates from five of the eight dogs contained components similar in buoyant density to human bronchitic glycoprotein. Glycoprotein isolated from the canine aspirates was similar to glycoprotein isolated from human chronic bronchitic sputum, having the same carbohydrate composition and range of oligosaccharide size. Further, during and after SO2 exposure some aspirates contained appreciable amounts of glycolipids. These data demonstrate substantial similarities in composition between normal human and canine mucus and in mucus isolated from dogs with chronic airway inflammation induced by repeated irritant exposure and from human patients with chronic bronchitis.

Animals↗
PubMed1987

Pathophysiology of bronchial hypersecretion.

Density gradient ultracentrifugation has been used to analyse the lavage from the proximal intrapulmonary bronchi of normal human volunteers and of dogs. The secretion from explants of canine trachea and human lobar bronchi has been examined under basal conditions and after stimulation by secretagogues. Mucus from the hypersecretory airways has been obtained from tracheostomized patients and from a canine model of chronic bronchitis produced by exposure to SO2 gas. No macromolecule of density gradient typical of an epithelial glycoprotein was recovered from normal basal secretions: the glycoconjugate recovered was of higher density and has sugars typical of a proteoglycan. The explant produced typical epithelial glycoprotein if stimulated. As volume of secretion increases, macromolecular yield does also, both of epithelial glycoprotein and of a number of lipids that are synthesised by the airway and which are different from alveolar lipids.

Animals↗
PubMed1987

Lipids in airway secretions.

Lipids form a significant portion of airway mucus yet they have not received the same attention that epithelial glycoproteins have. We have analyzed, by thin layer chromatography, lipids present in airway mucus under "normal" and hypersecretory (pathological) conditions. The 'normals' included (1) bronchial lavage obtained from healthy human volunteers and from dogs and (2) secretions produced "in vitro" by human (bronchial) and canine (tracheal) explants. Hypersecretory mucus samples included (1) lavage from dogs made bronchitic by exposure to SO2, (2) bronchial aspirates from acute and chronic tracheostomy patients, (3) sputum from patients with cystic fibrosis and chronic bronchitis and (4) postmortem secretions from patients who died from sudden infant death syndrome (SIDS) or from status asthmaticus. Cholesterol was found to be the predominant lipid in 'normal' mucus with lesser amounts of phospholipids. No glycolipids were detected. In the hypersecretory mucus, in addition to neutral and phospholipids, glycolipids were present in appreciable amounts, often the predominant species, suggesting that these may be useful as markers of disease. Radioactive precursors 14C acetate and 14C palmitate were incorporated into lipids secreted "in vitro" by canine tracheal explants indicating that they are synthesised by the airway.

Animals↗
PubMed1986

Density gradient analysis of secretions produced in vitro by human and canine airway mucosa: identification of lipids and proteoglycans in such secretions.

Human and canine airway mucosal explants synthesize and secrete high molecular weight glycoconjugates, incorporating 14C-glucosamine, a radioactive precursor to epithelial glycoprotein. Our examination of secretions produced by several individual specimens, however, did not reveal epithelial glycoprotein of typical buoyant density (1.5 g/ml in CsBr); only a high-density component with features of glycoprotein and proteoglycan. To provide sufficient material for characterization, secretions from several specimens of human and canine explants were separately pooled and subjected to DGU in CsBr. After removal of lipids and proteins, the glycoconjugates were recovered into five fractions of different density. 14C-glucosamine had been incorporated in all five fractions. Fractions 1-4 together accounted for 88% of the radiolabel but gas chromatography indicated that none of these contained epithelial glycoprotein. Their amino acid compositions were similar to those of proteoglycans and electrophoresis confirmed the presence of chondroitin sulfates A, B, C, heparan sulfate and hyaluronic acid. Sugars typical of epithelial glycoprotein were identified only in the glycoconjugate subfraction 5 of lowest density (and also lowest in yield) in which glycosaminoglycans were also identified. By addition of radioactive precursors, 14C acetate, 14C palmitate and 14C mevalonic acid to the culture medium and autoradiography of the secreted lipids we have shown that the tracheal explants actively synthesize lipids. Lipids accounted for a high proportion, almost half by weight, of the explant secretion. While neutral and phospholipids predominate, glycolipids were also identified.

Amino Acids↗
PubMed1985

Density gradient study of bronchial mucus aspirates from healthy volunteers (smokers and nonsmokers) and from patients with tracheostomy.

Because it is difficult to obtain, little is known of bronchial mucus from the normal human airway; it has been mainly studied as sputum expectorated in chronic bronchitis with particular attention to epithelial glycoprotein. We have now applied density gradient methods to study this and other macromolecules and lipids in normal airway mucus. After lavage at bronchoscopy, mucus was aspirated from six normal volunteers, that include one light and two heavy smokers. This normal mucus has been compared with that obtained from four patients with tracheostomy because of respiratory muscle paralysis due to neurological disease. The normal aspirates contained small threads of mucus, the tracheostomy aspirates viscous blobs of jelly, a difference in physical appearance reflected in macromolecular yields, 0.3-1 mg/ml and 6-24 mg/ml respectively. On analytical ultracentrifugation normal mucus showed no discernible material in the buoyant density region typical of epithelial glycoprotein (1.5 g/ml): Virtually all the material migrated to the miniscus and was predominantly lipids and proteins. A trace amount of material recovered from a higher density region (greater than or equal to 1.6 g/ml) was found to contain both glycoprotein and proteoglycan. Aspirates from the heavy smokers contained appreciable amounts of material with typical buoyant density (approximately 1.5 g/ml) but still with features of proteoglycan. In contrast in tracheostomy aspirates epithelial glycoprotein of typical buoyant density and chemical composition accounted for up to 25% of nondialyzable material. We conclude that under normal conditions typical epithelial glycoprotein is virtually absent from airway mucus and that the glycoconjugate present has features of glycoprotein and proteoglycan.

Adult↗
PubMed1984

Airway mucus: composition and regulation of its secretion by neuropeptides in vitro.

Human and canine airway mucosa in vitro synthesizes and secretes mucus glycoprotein, proteoglycans and lipids which can be separated by density gradient ultracentrifugation in caesium bromide. In secretions from unstimulated explants, the small amount of mucus glycoprotein present is found in association with proteoglycans. 'Free' mucus glycoprotein of typical buoyant density is present only after stimulation of submucosal gland secretion by methacholine. Lipids are synthesized, at least in part, by the airway mucosa and occur in explant secretions as a viscoelastic gel, suggesting that they significantly influence the rheological properties of airway mucus. In addition to cholinergic and adrenergic secretomotor neurons, the airway mucosa is innervated by peptidergic fibres containing immunoreactivity to vasoactive intestinal peptide (VIP) and substance P (SP). In explants of non-bronchitic human airway, VIP inhibits baseline glycoprotein and lysozyme secretion; in canine airway mucosa, by contrast, VIP is a weak partial secretory agonist. SP is the most potent agonist of canine airway glycoprotein release described to date and appears to evoke secretion by a direct action on a stereospecific SP receptor rather than by inducing release of other endogenous secretagogues. VIP and SP have little effect on glycoprotein discharge by mucous and serous cells of the submucosal gland; SP appears to induce secretion by causing contraction of submucosal gland ducts. This may represent the most rapid way for delivering mucus into the airway in response to injury or irritation of airway epithelium.

Animals↗
PubMed1984

Extracellular calcium ion depletion induces release of glycoproteins by canine trachea.

The effect of depletion of extracellular Ca2+ on the release by canine trachea in vitro of [14C]glucosamine-labeled trichloroacetic-phosphotungstic acid-precipitable glycoproteins was evaluated. Incubation in Ca2+,Mg2+-free medium containing ethyleneglycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA, 10(-3) to 10(-5) M) induced a time-dependent increase in base-line release of high molecular weight, radiolabeled glycoprotein that was not blocked by 10(-5) M atropine, propranolol, or phentolamine. Maximal increase was proportional to EGTA concentration and was augmented by preincubation with methacholine chloride. The secretory response was reversed by reincubation of explants in medium containing Ca2+, Sr2+, or Ba2+ but not Mg2+. Assessment of explants denuded of epithelium or cartilage indicated that the secretory response to depletion of Ca2+ originated in the tracheal submucosa, probably the submucosal glands. Quantitative autoradiographic analyses showed, however, that incubation in Ca2+,Mg2+-free medium had no effect on radiolabel release from mucous or serous cells in the tracheal submucosal glands. Increased radiolabeled glycoprotein release in Ca2+,Mg2+-free medium was accompanied by exfoliation of the surface epithelium, though the two effects were apparently unrelated. The secretory response was not due to cell lysis or increased release of radiolabeled glycosaminoglycans, and the finding that the specific activity (ratio of bound radiolabel to protein content) of the glycoprotein released was not changed in Ca2+,Mg2+-free medium showed that it was not due to a change in the rate of glycoprotein synthesis. A model is proposed in which depletion of Ca2+ increases the rate of flow of mucus from the duct lumens of the tracheal glands.

Animals↗
PubMed1979

Oral amphotericin for candidiasis in patients with hematologic neoplasms. An autopsy study.

Autopsy examinations were conducted in 72 patients with hematologic malignant neoplasms who received antibacterial therapy before their deaths. These patients were participants in a large double-blind study designed to assess the efficacy of oral amphotericin B in decreasing the incidence of candidal infection. The patients received either 50 mg of amphotericin B orally four times a day, or they received a matching placebo. Eight of 33 patients (24%) who had received placebo and two of 39 (5%) who had received amphotericin had histopathologic evidence of disseminated candidiasis. We conclude that in these patients with hematologic malignant neoplasms who received antibiotics within two weeks of death, the concomitant oral administration of amphotericin was effective in decreasing the incidence of systemic candidal infections, indicating that the gastrointestinal tract serves as a portal of entry for Candida albicans.

Administration, Oral↗
PubMed1979

Solid tumors complicating Hodgkin's disease. A report on two patients with immunoglobulin deficiency.

Multiple epithelial malignant neoplasms developed in two patients with Hodgkin's disease subsequent to radiotherapy and intensive chemotherapy. At the time of diagnosis, each patient also demonstrated a serum immunoglobulin deficiency. The significance of the occurrence of solid tumors in patients following therapy for Hodgkin's disease and the significance of cellular and humoral immunodeficiency in Hodgkin's disease in relation to second cancer development were studied. We suggest the establishment of a registry of leukemias and solid tumors developing in patients treated for Hodgkin's disease and other malignant neoplasms, possibly with detailed recording of immunocompetence data.

Adult↗