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Biomedical subjects

C E Johnson

Publications and source records attributed to C E Johnson.

At least 109 records · Page 6Linked to original sources
PubMed1989

Management of allergic rhinitis: focus on intranasal agents.

The clinical manifestations of allergic rhinitis are the result of an immune-mediated process after exposure of a sensitized individual to airborne allergens. The primary symptomatology includes nasal congestion, rhinorrhea, nasal and conjunctival pruritus, and sneezing. Principles of management include allergen avoidance, palliative therapy, immunotherapy, and pharmacotherapy. Oral decongestants stimulate alpha-adrenergic receptors in the nasal cavity, resulting in vasoconstriction and decreased edema. Oral antihistamines block histamine1 (H1) receptors, and may relieve rhinorrhea, sneezing, and nasal and conjunctival pruritus. Topical decongestants have a local effect on adrenergic receptors in the nasal mucosa, resulting in rapid, marked vasoconstriction. Intranasal corticosteroids inhibit mediator release from mast cells and basophils, and reduce edema of the nasal mucosa. Dexamethasone sodium phosphate, beclomethasone dipropionate, and flunisolide are currently available for intranasal administration. Cromolyn sodium inhibits allergen-induced degranulation and mediator release from sensitized cells, and is useful primarily as a prophylactic agent. Several agents, including the corticosteroids budesonide and flucortin butylester, the mast cell-stabilizing agent nedocromil sodium, the anticholinergic agent ipratropium bromide, and the H1 receptor antagonist levocabastine are being investigated for intranasal use in the management of allergic rhinitis.

Administration, Intranasal↗
PubMed1989

Molecular epidemiology of adhesin and hemolysin virulence factors among uropathogenic Escherichia coli.

The pap, prs, pil, and hly operons of the pyelonephritic Escherichia coli isolate J96 code for the expression of P, F, and type 1 adhesins and the production of hemolysin, respectively; the afaI operon of the pyelonephritic E. coli KS52 encodes an X adhesin. Using different segments of these operons as probes, colony hybridizations were performed on 97 E. coli urinary tract and 40 fecal clinical isolates to determine (i) the presence in the infecting bacteria of nucleotide sequences related to virulence operons, and (ii) the phenotypic properties associated with such sequences. Coexpression of P and F adhesins encoded by pap-related sequences was detected more frequently among isolates from patients with pyelonephritis (32 of 49, 65%) than among those with cystitis (11 of 48, 23%; P less than 0.0001) or from fecal specimens (6 of 40, 15%; P less than 0.0001). Therefore, the expression of both adhesins appears to be critical in the colonization of the upper urinary tract. In contrast, afaI-related sequences were detected significantly more frequently among isolates from patients with cystitis, suggesting that this class of X adhesin may have a role in lower urinary tract infections. Urinary tract isolates differed from fecal isolates by a low incidence of type 1 adhesin expression among pil probe-positive isolates. hly-related sequences were only detected in pap probe-positive isolates. The frequency of hemolysin production among pap probe-positive isolates was not associated with a particular pattern of infection. The distribution of these virulence factors was similar in the presence or absence of reflux, indicating that structural abnormalities of the urinary tract did not facilitate colonization by adhesin-negative isolates.

Adhesins, Escherichia coli↗
PubMed1989

Structure and copy number of gene clusters related to the pap P-adhesin operon of uropathogenic Escherichia coli.

The structurally related pap and prs operons of the uropathogenic Escherichia coli isolate J96 encode a P and an F adhesin that mediate bacterial attachment to the human P blood group antigen and the Forssman antigen, respectively. Using probes prepared from different segments of the pap operon, Southern blot hybridizations were performed to characterize pap-related sequences of 30 E. coli clinical isolates expressing different adhesin phenotypes. Gene clusters encoding P and F adhesins displayed no restriction site polymorphism in sequences homologous to the papH, papC, and papD genes that encode proteins essential to the transport and polymerization of the subunits of the P-pilus adhesin. In contrast, pap-related genetic elements associated with a null phenotype either lacked homology to the papH, papC, and papD genes or displayed a restriction site polymorphism in this region. Sequences within and surrounding the J96 papG and prsG adhesin genes that determine the binding specificities to the P and F antigens, respectively, were not conserved. However, gene clusters encoding different binding specificities could not be distinguished based on such restriction site polymorphisms. The majority of clinical isolates had more than one copy of pap-related sequences that involved gene clusters similar to the J96 pap operon, as well as genetic elements that were related only to a part of this operon. The implications of this unexpected copy number polymorphism with respect to possible recombination events involving pap-related sequences are discussed.

Adhesins, Escherichia coli↗
PubMed1989

Etoposide compared with the combination of vincristine, doxorubicin, and cyclophosphamide in the treatment of small cell lung cancer.

One hundred and three patients with small cell lung carcinoma were stratified according to stage of disease (47 limited disease, 56 extensive disease) and then randomised to receive etoposide 300 mg/m2 alone for two days or a combination (VAC) of vincristine 1 mg/m2, doxorubicin (Adriamycin) 50 mg/m2, and cyclophosphamide 1000 mg/m2. The drugs were given at three week intervals. Patients were assessed after three cycles of treatment and continued with the same regimen if in complete remission and with the alternative regimen if in partial remission; they were withdrawn if the disease had progressed. Twenty four patients (23%) achieved complete remission and this occurred more often when patients were receiving VAC (19 of 82) than etoposide (5 of 75). There was no difference, however, in overall survival between those initially treated with etoposide and those having combination chemotherapy, whether for limited disease (both 8 months) or extensive disease (7 and 5.5 months). Toxicity was less with etoposide. Survival was disappointing, especially with limited disease, even in patients who showed a complete response to treatment.

Actuarial Analysis↗
PubMed1989

Evaluation of five procedures for measuring nonstandard doses of nifedipine liquid.

Five methods for removing the maximum volume of liquid from a nifedipine capsule were evaluated for efficiency and reproducibility, and the concentration of nifedipine in Procardia and Adalat 10- and 20-mg capsules was determined The methods evaluated were the needle puncture and squeeze method; the scissors method; the needle and syringe, one-hole method; the needle and syringe, two-hole method; and the capsule in syringe barrel method. The liquid content of 10 Adalat 10-mg capsules was removed by each method, the volume was determined by the weight and specific gravity of the nifedipine liquid, and the mean volumes of nifedipine liquid were compared. A stepwise procedure for using the needle and syringe, one-hole method was developed. The mean nifedipine concentration in Procardia 10- and 20-mg capsules was determined by ultraviolet spectrophotometry by using 30 capsules of each brand and strength. The needle and syringe methods were the most reproducible and efficient procedures for obtaining a desired milligram dosage of nifedipine from the capsules. The two-hole method would be less practical in the clinical setting, however, because it is time consuming and cumbersome. The mean assayed nifedipine concentration in the Procardia and Adalat 10- and 20-mg capsules was within 10% of the concentration reported by the manufacturer for each specific product lot number. Based on reproducibility and efficiency, the needle and syringe methods are the best methods for quantitation of liquid nifedipine doses for patient administration.

Capsules↗
PubMed1989

Principles of nebulizer-delivered drug therapy for asthma.

The principles of aerosol drug delivery by compressed-air nebulization are described, and the therapeutic agents administered by this process for management of asthma are reviewed. For therapy of acute and chronic asthma, aerosol inhalation has become the primary method of drug administration. Aerosolized particles with aerodynamic diameters of 1 to 5 microns are most efficiently deposited in the lower respiratory tract. Delivery systems for therapeutic aerosols include compressed-air nebulizers and metered-dose inhalers. Compressed-air nebulizers are less efficient than metered-dose inhalers; therefore, the drug dosages recommended for nebulizer solutions are 3 to 10 times higher than those delivered by a metered-dose inhaler. Because many asthma patients are treated with nebulization drug therapy at home, both patients and pharmacists must understand how to use the equipment correctly. Drugs used in aerosol therapy of acute and chronic asthma include the beta 2-receptor agonists epinephrine, isoproterenol, isoetharine, metaproterenol, terbutaline, and albuterol; cromolyn sodium; and the anticholinergic agents atropine and ipratropium bromide. Terbutaline and albuterol have longer durations of action and greater beta 2-receptor selectivity than metaproterenol, isoetharine, and isoproterenol. Cromolyn is a first-line prophylactic agent for asthma management. Atropine is indicated for maintenance therapy of chronic asthma and in combination with the beta 2-receptor agonists for therapy of acute asthma; ipratropium bromide is a new agent similar to atropine but with substantially fewer adverse effects. Acute and chronic asthma may be managed by aerosol administration of beta 2-receptor agonists, cromolyn, and atropine, alone or in combination. Inhalation is the preferred route of drug delivery because small doses of medication provide maximal therapeutic benefit with minimal adverse effects.

Aerosols↗
PubMed1989

Compatibility of aminophylline and verapamil in intravenous admixtures.

The chemical and visual compatibility of aminophylline and verapamil hydrochloride in intravenous admixtures was evaluated. Verapamil hydrochloride injection was added to a solution of aminophylline 1.0 mg/mL in 5% dextrose injection (D5W) to yield final verapamil hydrochloride concentrations of 0.1 and 0.4 mg/mL. Each solution type was prepared in triplicate. An aliquot from each of these solutions was assayed in duplicate for theophylline and verapamil by high-performance liquid chromatography at 0, 4, 8, 12, and 24 hours after mixing. All aliquots were filtered with a 0.22-micron filter immediately before assay. At each time interval, samples were assessed for pH and inspected visually and microscopically for evidence of incompatibility. Theophylline concentrations showed less than 10% change over 24 hours in the two-drug admixtures. Less than 1% of the original verapamil concentrations remained immediately after mixing with aminophylline injection in D5W. Turbidity was readily apparent in the admixture containing verapamil hydrochloride 0.4 mg/mL; however, microscopic evaluation revealed precipitate in both solutions. Solution pH was determined to be a primary cause of precipitation. The mean pH values for the verapamil hydrochloride 0.1 and 0.4 mg/mL control solutions were 4.09 and 4.36, respectively. The mean pH of the aminophylline 1.0 mg/mL control solution was 8.35. The mean pH of the aminophylline-verapamil admixtures at verapamil hydrochloride concentrations of 0.1 and 0.4 mg/mL was 8.14 and 8.06, respectively. Verapamil hydrochloride injection in final concentrations of 0.1 and 0.4 mg/mL is incompatible with aminophylline 1.0 mg/mL in D5W.

Aminophylline↗
PubMed1989

Stability of alcohol-free theophylline liquid repackaged in plastic oral syringes.

The stability of an alcohol-free liquid theophylline product repackaged and stored in polypropylene oral syringes was studied. A commercially available alcohol-free liquid theophylline preparation was repackaged in the following unit dose syringes: 3- and 10-mL clear polypropylene syringes and 3- and 10-mL amber polypropylene syringes. Fifty syringes of each type were prepared. The 3-mL syringes were filled with 2 mL of theophylline, while the 10-mL syringes were filled with 7 mL of the liquid. All syringes were stored at room temperature under continuous fluorescent lighting. The mean volume of theophylline delivered from six syringes of each type was determined on days 0, 14, 30, 60, 90, and 180 after repackaging. The samples were assayed for theophylline content by high-performance liquid chromatography. The theophylline dose delivered ranged from 96.2% to 101.7% of the initial repackaged dose. The difference in theophylline concentrations remaining among the types of syringes after 180 days of storage was not significant. The volume of theophylline delivered decreased and the concentration increased as a probable result of water evaporation over time. Alcohol-free theophylline liquid repackaged in 3- and 10-mL clear or amber disposable polypropylene unit dose syringes can be stored at room temperature under continuous fluorescent light for at least 180 days.

Drug Stability↗
PubMed1988

Live attenuated varicella vaccine in healthy 12- to 24-month-old children.

We studied live attenuated Oka/Merck varicella vaccine in 147 seronegative children 12 to 24 months of age and their 94 seronegative older siblings 2 to 12 years of age. The vaccine side effects were mild, consisting of a papular rash in 15 of 147 (10.2%) children 12 to 24 months and seven of 94 (7.4%) siblings. In a subset of 12- to 24-month-old children, modified fluorescent antibody test for membrane antigen was not detectable at seven days postimmunization but was detectable in 50% by 14 days and in 100% by 21 days. Within 6 weeks, 96.6% of children 12 to 24 months and 94.7% of siblings seroconverted. The geometric mean titer did not vary with age at immunization. One-year blood samples were obtained from 70 children 12 to 24 months of age who seroconverted; 92.9% retained detectable antibody. The geometric mean titer had decreased from 55.7 to 18.6. Of these 70 children, 34% had been exposed to varicella since immunization, and two cases of varicella were observed in seroconverters. Both cases were mild, with less than 50 vesicles. Oka/Merck varicella vaccine appears to be safe, highly immunogenic, and protective against 96% of exposures to natural varicella during the first year after vaccination in infants. Those cases of varicella that develop in immunized children appear substantially reduced in severity.

Antibodies, Viral↗
PubMed1988

Recognizing borderline personality disorder in the primary care client.

The nurse practitioner is responsible for the diagnosis and treatment of a great variety of physical and psychological disorders in the ambulatory client. Frequently the diagnosis of personality disorder is missed, ignored or not even considered. This article will introduce the nurse practitioner to the various personality disorders. The main focus, borderline personality disorder, is estimated to affect 5 to 15 percent of the general population. A picture of the borderline client from etiology to treatment as well as recent research findings and suggestions for history taking and physical exam are covered. Borderline has been a difficult and confusing diagnosis to make because in the past the term has had several different meanings. This article will clarify what this diagnosis means, and will assist the nurse practitioner in the recognition, diagnosis and management of all clients with personality disorders.

Adult↗
PubMed1988

Management of hypophosphatemia.

The etiology, clinical presentation, and management of hypophosphatemia are reviewed. Phosphorus is a major intracellular anion and plays an important role in many biochemical pathways relating to normal physiologic functions. Approximately 60 to 90% of the 1 to 1.5 g of daily dietary phosphorus intake is absorbed, and of that amount, about two thirds is excreted in the urine. The overall incidence of hypophosphatemia is about 2 to 3% of all hospitalized patients. Factors associated with hypophosphatemia include phosphate-binding antacid therapy, nasogastric suction, liver disease, sepsis, alcoholism, and acidosis associated with diabetic ketoacidosis. Patients receiving parenteral nutrient solutions were also at higher risk for hypophosphatemia before the routine supplementation of these formulations with phosphate. Patients with hypophosphatemia may be asymptomatic or may experience weakness, malaise, anorexia, bone pain, and respiratory arrest. The major systems involved include the neuromuscular, hematologic, and skeletal systems. Phosphorus-containing products used to treat hypophosphatemia are a combination of monobasic and dibasic phosphate salts. Therefore, it is essential to calculate doses in millimoles rather than milligrams or milliequivalents to more accurately reflect the phosphorus concentration and to avoid potentially serious dosage errors. Normal daily requirements are readily maintained by dietary sources of phosphorus such as milk products or may be supplemented by phosphate-containing products administered orally or intravenously. Since phosphorus is a key factor in many organ systems, it is essential to monitor serum phosphorus concentrations in patients at risk for hypophosphatemia.

Humans↗
PubMed1988

Compatibility of premixed theophylline and verapamil intravenous admixtures.

The stability of verapamil hydrochloride injection when mixed with a commercial product of premixed theophylline in 5% dextrose injection was studied. Solutions containing theophylline in concentrations of 4.0 and 0.4 mg/mL were used. Verapamil hydrochloride was added to each theophylline solution to produce final verapamil concentrations of 0.4 mg/mL and 0.1 mg/mL. Each admixture was prepared in triplicate, and samples were kept at room temperature in glass. Immediately after mixing and at 4, 8, 12, and 24 hours, samples were visually inspected, tested for pH, filtered, and assayed in duplicate by high-performance liquid chromatography for theophylline and verapamil concentrations. Control solutions containing only one of the two drugs were also tested. No visual changes were observed. The addition of the verapamil hydrochloride injection to the theophylline in 5% dextrose injection resulted in decreased mean pH values of 4.29 and 4.37 for all solutions compared with 4.80 and 4.90 for the verapamil control samples at concentrations of 0.4 and 0.1 mg/mL. These values did not vary significantly throughout the study period. Theophylline and verapamil concentrations did not change significantly compared with baseline or control solutions during the study period. Verapamil hydrochloride injection in final concentrations of 0.1 to 0.4 mg/mL can be added to a commercial preparation of premixed theophylline in 5% dextrose injection in concentrations of 0.4 to 4.0 mg/mL and administered intravenously within 24 hours of mixing without loss of potency of either drug.

Chromatography, High Pressure Liquid↗
PubMed1987

Augmentation of skin test reactivity and lymphocyte blastogenesis in patients with AIDS treated with transfer factor.

Nine patients with the acquired immunodeficiency syndrome (AIDS) were administered four doses of pooled transfer factor obtained from the lymphocytes of three healthy controls and three homosexuals with stable lymphadenopathy and serum antibody to the human immunodeficiency virus. Before receiving transfer factor, all patients exhibited anergy to skin test antigens. After four weeks of transfer factor therapy, six of seven patients tested had at least one skin test response. Lymphocyte blastogenic responses to phytohemagglutinin rose from a stimulation index of 6.77 +/- 1.31 before treatment to 19.77 +/- 6.24 after four weeks of transfer factor therapy. Smaller but significant increases were also seen in blastogenic responses to antigens. Improvements in immune responses diminished after administration of transfer factor was halted. Thus, administration of transfer factor to patients with AIDS resulted in partial immune reconstitution. Further studies are indicated to examine the clinical efficacy of this immune response modifier in the treatment of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Early recurrences of otitis media: reinfection or relapse?

In a prospective study, 36 (35%) of 103 patients had early recurrence of acute otitis media. We wished to identify risk factors for early recurrences (those recurring within 1 month of initial diagnosis) and to determine if the second episode was caused by the same pathogen (relapse) or a new organism (reinfection). When the same bacterial species was recovered in both episodes, Streptococcus pneumoniae were serotyped and Haemophilus influenzae were classified by biotypes and by electrophoretic pattern of the outer membrane proteins. Twenty-nine patients underwent tympanocentesis at the time of the recurrent episode. In 13, no pathogen was recovered either initially or at the time of recurrence. Twelve (75%) of the remaining 16 patients had reinfection; only four (25%) had relapse. Thus, early recurrences of acute otitis media were more often caused by a new organism. This finding suggests that underlying susceptibility to middle ear infection is important in the development of recurrent otitis media. Pediatricians should not assume that early recurrences are necessarily the result of failure of initial treatment. Tympanocentesis may be helpful in this setting to aid in choosing appropriate antibiotic therapy.

Acute Disease↗