Biomedical subjects
B R Gordon
Publications and source records attributed to B R Gordon.
Low-density lipoprotein apheresis using the Liposorber dextran sulfate cellulose system for patients with hypercholesterolemia refractory to medical therapy.
A subset of patients with familial hypercholesterolemia (FH) have an inadequate lipid-lowering response to diet and drug treatment and should be considered for low-density lipoprotein (LDL)-apheresis therapy. This procedure selectively removes apolipoprotein B-containing particles [LDL, very-low-density lipoprotein, lipoprotein(a)] from plasma independent of diet and drug therapy. Methods for performing LDL-apheresis include dextran sulfate cellulose adsorption, immunoadsorption, and heparin-induced extracorporeal precipitation. The Liposorber Study Group evaluated LDL removal using the Liposorber LA-15 LDL-apheresis System in 64 patients with FH who had not responded adequately to diet and maximal drug therapy. Mean acute reductions in LDL cholesterol (LDL-C) were 76% in heterozygous FH (HtFH) patients and 81% in homozygous FH (HoFH) patients. Time-averaged levels of LDL-C were lowered 41% in HtFH and 53% in HoFH patients. Hypotension was the most frequent side effect, occurring in 3% of procedures. The Liposorber LA-15 System has been approved by the Food and Drug Administration and is recommended for 1) patients with functional homozygous FH (LDL-C level > 500 mg/dL; 2) patients with coronary artery disease (CAD) and LDL-C levels > or = 200 mg/dL; 3) patients without CAD, but an LDL-C level > or = 300 mg/dL.
Low lipid concentrations in critical illness: implications for preventing and treating endotoxemia.
OBJECTIVES: To determine the prevalence and clinical significance of hypolipidemia found in critically ill patients, and whether the addition of a reconstituted lipoprotein preparation could inhibit the generation of tumor necrosis factor-alpha (TNF-alpha) in acute-phase blood taken from these patients. SETTING: Surgical intensive care unit (ICU) of a large urban university hospital. DESIGN: Prospective case series. PATIENTS: A total of 32 patients with a variety of critical illnesses had lipid and lipoprotein concentrations determined. Six patients and six age- and gender-matched control subjects had whole blood in vitro studies of the effect of lipoprotein on lipopolysaccharide mediated TNF-alpha production. INTERVENTIONS: Blood samples were drawn on admission to the ICU and over a subsequent 8-day period. MEASUREMENTS AND MAIN RESULTS: Mean serum lipid and lipoprotein values obtained from patients within 24 hrs of transfer to the surgical ICU were extremely low: mean total cholesterol was 117 mg/dL (3.03 mmol/L), low-density lipoprotein cholesterol 71 mg/dL (1.84 mmol/L), and high-density lipoprotein cholesterol 25 mg/dL (0.65 mmol/L). Only the mean triglyceride concentration of 105 mg/dL (1.19 mmol/L), and the mean lipoprotein(a) concentration of 25 mg/dL (0.25 g/L) were within the normal range. During the first 8 days following surgical ICU admission, there were trends toward increasing lipid and lipoprotein concentrations that were significant for triglycerides and apolipoprotein B. Survival did not correlate with the lipid or lipoprotein concentrations, but patients with infections had significantly lower (p = .008) high-density lipoprotein cholesterol concentrations compared with noninfected patients. Lipopolysaccharide-stimulated production of TNF-alpha in patient and control blood samples was completely suppressed by the addition of 2 mg/mL of a reconstituted high-density lipoprotein preparation. CONCLUSIONS: Patients who are critically ill from a variety of causes have extremely low cholesterol and lipoprotein concentrations. Correction of the hypolipidemia by a reconstituted high-density lipoprotein preparation offers a new strategy for the prevention and treatment of endotoxemia.
Current status of low density lipoprotein-apheresis for the therapy of severe hyperlipidemia.
The use of LDL-apheresis to treat patients with severe hypercholesterolemia has gained wider clinical acceptance during the past 2-3 years, particularly in patients with coronary artery disease. Systems utilizing immunoadsorption columns, dextran sulfate cellulose columns and heparin precipitation have been most commonly employed. New or improved technologies include whole-blood compatible columns, double-filtration plasmapheresis and lipoprotein (a)-apheresis. The mechanisms for clinical improvement extend beyond simple regression of atherosclerotic plaque.
Asthma: an important disease to otolaryngologists--Part I: Suspecting and diagnosing asthma.
Asthma is a chronic inflammatory disease of the lower respiratory tract which is triggered by exposure to allergens or other airway irritants. This inflammation results in airway hyperresponsiveness, bronchial muscle spasm, mucous gland hypersecretion and mucosal edema, which combine to create symptoms such as cough, wheezing and respiratory distress. Because the inflammatory process is highly variable, asthma is a disorder with many possible presentations. It may therefore proceed for years without clinical recognition, and may challenge the most astute diagnostician. It is important for otolaryngologists to be able to suspect, diagnose and treat asthma. This is so because asthma is a common disease in the otolaryngologic patient population, both as one of the options in the differential diagnosis of respiratory complaints, and as a comorbid condition which may complicate the treatment of other medical or surgical problems. Furthermore, both the understanding of asthma's pathophysiology, and its optimum treatment methods have undergone radical changes during the past decade. This three-part discussion reviews our modern understanding of asthma, and proposes diagnosis and treatment guidelines which can assist otolaryngologists in effectively managing their asthmatic patients. Part one summarizes current information on the pathophysiology and increasing prevalence of asthma, its clinical variability, the assessment of asthma sensitivity, and methods for diagnosis of asthma. Parts two and three cover the strategy for asthma management, and the use of both adjunctive and anti-inflammatory therapies for asthma control.
Asthma: an important disease to otolaryngologists--Part II: Asthma management strategy.
Asthma is a chronic inflammatory disease of the lower respiratory tract which is triggered by exposure to allergens or other airway irritants, and is commonly encountered in otolaryngologic practice. This three-part review is designed to assist otolaryngologists in effectively managing their asthmatic patients. In Part I, current information on the pathophysiology and increasing prevalence of asthma, its clinical variability, the assessment of asthma severity and methods for diagnosis of asthma were summarized. Part II discusses a tripartite strategy for asthma management, based on environmental controls, the use of anti-inflammatory therapies and patient education. In addition, pharmacologic treatments which are not primarily anti-inflammatory are reviewed in detail. The uses, effectiveness, side effects and suitability for drug combination therapy for mucolytic, anticholinergic, antihistamine, theophylline and beta agonist drugs are compared, and the disadvantages of beta antagonists are summarized. Part III concludes with an overview of anti-inflammatory therapies for asthma control.
Asthma: an important disease to Otolaryngologists--part III: anti-inflammatory therapy.
Asthma is a chronic inflammatory disease of the lower respiratory tract which is triggered by exposure to allergens or other airway irritants, and is commonly encountered in otolaryngologic practice. This three-part review is designed to assist otolaryngologists in recognizing and managing asthmatic patients. Part one summarized current knowledge of the pathophysiology and increasing prevalence of asthma, and its assessment and diagnosis. Part two discussed asthma management by environmental controls, anti-inflammatory therapies, and patient education, and compared pharmacologic treatments which are not primarily anti-inflammatory. These include mucolytic, anticholinergic, antihistamine, theophylline and beta agonist drugs. In this final part, anti-inflammatory treatments for asthma control are critically reviewed, including a balanced discussion of cromolyn, nedocromil, glucocorticoids, allergy immunotherapy, and the appropriate indications, possible toxicities and reasonable precautions for their use.
Lipoprotein(a) levels in patients receiving renal replacement therapy: methodologic issues and clinical implications.
Lipoprotein(a) [Lp(a)] is a genetically determined risk factor for vascular disease and a potential link between coagulation, lipoproteins, and the development of atherosclerosis. Its role in the vascular complications of patients with chronic renal disease is unclear. We review methodologic issues involved in measuring Lp(a), particularly as they relate to studies of patients with chronic renal disease. The accurate measurement of Lp(a) is difficult because all the commercially available assays are sensitive to apolipoprotein(a) isoform size, Lp(a) behaves like an acute phase reactant, and levels vary markedly among ethnic groups. The results of 12 studies that included data on median Lp(a) levels in controls and patients receiving renal replacement therapy were analyzed. Although there was variation among studies, most found elevated levels of Lp(a) in patients receiving hemodialysis (range of medians, 9.0 to 38.4 mg/dL) compared with controls (range of medians, 4.7 to 19.7 mg/dL). With the exception of one study, Lp(a) levels also were elevated in patients receiving continuous ambulatory peritoneal dialysis compared with controls and patients receiving hemodialysis. In one study, an elevated Lp(a) level in patients receiving hemodialysis correlated with subsequent development of vascular events. A separate study associated the occurrence of vascular access occlusion with Lp(a) level. Following renal transplantation, Lp(a) levels decreased in all four studies, which included data before and after transplantation. Although variability in results were seen, Lp(a) levels appear to be elevated in patients receiving renal replacement therapy. Renal transplantation at least partially reverses this effect. The variability in results is probably related to methodologic difficulties in measuring Lp(a) and failure to segregate ethnic groups in study design and analysis.(ABSTRACT TRUNCATED AT 250 WORDS)
Immunotherapy basics.
Immunotherapy is the use of controlled exposure to allergens to produce durable antiinflammatory effects, thus reducing the severity of allergic disorders. Immunotherapy is useful when other methods of allergy therapy are not fully satisfactory and can be effectively combined with rhinologic surgical treatment. Immunotherapy should always be considered as a treatment option for allergy patients and can often be of benefit, provided that appropriate indications and contraindications are observed. Physicians caring for patients with allergies should therefore become familiar with methods of allergy and diagnosis and with the therapeutic potential of immunotherapy. The history of immunotherapy, possible mechanisms, indications, contraindications, testing methods, and initiation of treatment are reviewed.
Future immunotherapy: what lies ahead?
There is currently great interest in developing improved methods of immunotherapy and new techniques of immune system manipulation to ameliorate allergic diseases. This article reviews current research trends in the immunologic treatment of allergy, including the use of chemically modified allergens, nonparenteral allergen exposure, sustained-release allergen delivery, anti-immunoglobulin E antibodies, gamma-globulin, immune complexes, cytokines, and T-cell-tolerogenic peptides.
Indications for low-density lipoprotein apheresis.
Low-density lipoprotein (LDL) apheresis offers an additional approach to lipid lowering in patients with severe hypercholesterolemia who fail to respond adequately to diet and drug therapy. Well-defined criteria for patient selection have yet to be established for LDL apheresis. This study proposes guidelines based on whether coronary artery disease (CAD) is present and on the degree of LDL cholesterol elevation after treatment with diet and maximal drug therapy. It is reasonable to consider LDL apheresis therapy for: (1) patients with CAD and LDL cholesterol levels > 190 mg/dl; (2) patients without CAD, but at high risk for disease due to an LDL cholesterol level > 250 mg/dl, a first-degree relative with premature CAD, and the presence of > or = 1 additional risk factor. In addition, LDL apheresis is recommended for the management of all patients with homozygous familial hypercholesterolemia due to the very high risk of CAD and the poor response to usual lipid-lowering treatments.
Beginner's guide to primary inhalant allergens. Part 5: Tree families.
Explore the source record for details and available documents.
Beginner's guide to primary inhalant allergens. Part 6: Gymnosperm (coniferous) trees.
Explore the source record for details and available documents.
Beginner's guide to primary inhalant allergens. Part 3: Weed and fern families.
Explore the source record for details and available documents.
Beginner's guide to primary inhalant allergens. Part 4: Non-asteracean weed families.
Explore the source record for details and available documents.
Beginner's guide to primary inhalant allergens. Part 1: Introduction to pollens.
Explore the source record for details and available documents.
Allergic rhinosinusitis: the total rhinologic disease.
Allergic rhinosinusitis has three forms of therapy: pharmacotherapy, immunotherapy, and surgical therapy. Pharmacotherapeutically, there are six classes of drugs that give symptomatic relief: mucolytics, decongestants, anti-cholinergic agents, antihistamines, mast cell stabilizers, and corticosteroids. All six classes are discussed individually and in detail. For immunotherapeutic therapy of allergic rhinosinusitis, there are four types of skin testing in current use: scratch testing, prick testing, single intradermal testing, and skin end point titration testing. Only the latter is able to quantitate the antigenicity of each antigen, and thus the treatment vial made from only this type of skin testing can adequately treat all antigens to which the patient is sensitive. These differences in testing and vial mixing are explained. The last form of therapy is surgical therapy, which corrects the obstructive phenomenon caused by allergic rhinosinusitis. The procedures described are reduction inferior turbinectomies and endoscopic sinus surgery. It is felt by the authors that the specialist who is uniquely positioned to offer a patient suffering from allergic rhinosinusitis all three forms of therapy is the rhinologist.