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Biomedical subjects

J S Gardner

Publications and source records attributed to J S Gardner.

9 recordsLinked to original sources
PubMed1990

An epidemiologic postmarketing surveillance study of prescription acne medications.

After the Food and Drug Administration approved a topical antibiotic for the treatment of acne, we began a postmarketing surveillance study to measure the frequency of antibiotic-associated colitis and diarrhea in acne patients treated with topical antibiotics and low doses of oral antibiotics. Pharmacists recruited 13,465 patients who presented a prescription for an acne medication, and we obtained detailed information on the use of the medications, perceived acceptability, and the occurrence of new health events from 6,453 with computer-assisted telephone interviews. Three cases (less than 0.1%) of antibiotic-associated diarrhea and one case (less than 0.1%) of antibiotic-associated colitis were confirmed. We conclude that this methodology can provide further information about the safety of a drug once it is in customary use, at a fraction of the cost of Phase III clinical trials.

Acne Vulgaris↗
PubMed1990

Human hair morphology: a scanning electron microscopy study on a male Caucasoid and a computerized classification of regional differences.

The present study was performed to provide a better understanding of the morphological variations of mammalian hair. Terminal hair samples were obtained from different regions of the body of the same Caucasian male. All hair samples were either cleaned or treated before being examined with scanning electron microscopy. As human scalp hair grew it appeared small like lanugo hair, but the increase in diameter appeared to have been relatively rapid. As hair increased in diameter the appearance of the scales changed. Neck hair was slightly smaller in diameter than scalp hair, and axillary hair was slightly smaller in diameter than neck hair. Nostril hair was larger than scalp or axillary hair. Eyelash hair was much smaller and much shorter than eyebrow hair. Neck hair, forearm hair, and shin hair were smaller than hair from most other regions of the body. Chest hair was similar in size to scalp hair, and pubic and sideburn hair were larger than scalp hair. A morphological feature called "steak-boning" was more characteristically present in whiskers of Caucasoids than Orientals or Blacks. "Steak-boning" occurred most frequently in hair of the mustache, followed by that of the chin, sideburn, cheek and under the chin. Cut surfaces of whiskers were different for electric as compared with straightedge razors. Hair morphology varied relative to the body region. Computer analysis of resin-embedded hair made it possible to classify arm, mustache, cheek, chin, head, shin, and pubic hair, and to quantify cross-sectioned differences.

Hair↗
PubMed1985

A quantitative stability analysis of human monoclonal antibody production by heteromyeloma hybridomas, using an immunofluorescent technique.

We describe a quantitative method of analysis for assessing stability of human monoclonal antibody production by hybridomas. Clones derived from fusion between the SHM-D33 heteromyeloma line and EBV-stimulated human lymphocytes were studied for antibody presence using a fluorescent labelling technique. Frequencies of antibody-negative variants in clonal populations were measured, and measurements on parallel clonal populations were subjected to Luria-Delbrück fluctuation analysis to compute rates of generations of antibody-negative cells. Independent hybridoma clones exhibited a range of stabilities and the corresponding rates varied between 5 X 10(-4) and 6 X 10(-2) cell-1 generation-1. Rates of generation of antibody-negative variants for the more stable heteromyeloma hybridomas compared well with those of 2 established mouse hybridoma lines tested (less than 10(-3) cell-1 generation-1). There was a positive correlation between frequency of antibody-negative variants measured in clonal populations grown to large numbers of cells (greater than 10(7) per culture) and their rate of loss of antibody production. Large variations in frequency of antibody-negative variants were observed in parallel clonal populations, suggesting that loss of ability to produce antibody is due to random, mutation-like events including chromosome loss (Luria and Delbrück, 1943). High frequencies of antibody-negative variants may indicate imminent loss of antibody-producing capacity by a clone growing in suspension culture.

Antibodies, Monoclonal↗
PubMed1977

Ultrastructure of lipid bodies in Tilletia caries teliospores.

The ultrastructure of lipid bodies within developing, dormant, and germinating Tilletia caries (DC). Tul. (race T-16) teliospores was studied by freeze-etching and thin-sectioning techniques. When teliospores were prefixed in sodium cacodylate-buffered glutaraldehyde-acrolein for 24 h before further processing, most of the lipid bodies appeared to have a uniformly osmiophilic matrix. Some of these lipid bodies were surrounded by thin electron-dense lines that appeared to be half-unit membranes. Occasionally this membrane seemed to be absent, allowing for a direct interface between lipid and cytosol. Irregular electron-dense patterns were occasionally observed in lipid bodies of developing, dormant, and germinating teliospores. A lamellar substructure with 6- to 10-nm center-to-center spacing was visible in the electron-dense patterns at high magnifications. Irregular fracture patterns were visible in freeze-etch replicas.

Basidiomycota↗
PubMed1976

Solid-phase, magnetic particle radioimmunoassay.

A solid-phase radioimmunoassay system has been developed based on the use of antibodies covalently linked to polymer-coated iron oxide (EnzacrylR). An electro-magnet is employed both to mix the particles during incubation (by switching the field on and off) and to separate the antibody-bound and free fractions. This obviates the need for vertical rotation and for the time-consuming, multiple centrifugations required with conventional solid phase procedures. The system is universally applicable and methods have been established for the assay of thyroxine, human placental lactogen and digoxin. The thyroxine assay was employed as a model and it was shown that the results obtained for serum samples correlated closely with those using a routine liquid-phase radioimmunoassay. The applicability of employing a second antibody linked to the iron oxide particles was also studied.

Binding Sites, Antibody↗
PubMed1975

Fixation of dormant Tilletia teliospores for thin sectioning.

Dormant Tilletia caries teliospores in fixative solution or distilled water were frozen onto specimen chucks of an FTS Sorvall-Christensen frozen thin sectioner and cut or fractured at various temperatures (-20 C to -75 C) and thickness settings (10, 15, 20 and 25 mum). Cytoplasm of dormant spores was well preserved and organelles were found to differ from those of germinated spores in morphology. This procedure makes it possible to fix adequately dormant spores and thus compare the ultrastructure and histochemistry of dormant spores with those of germinated spores.

Fungi↗