Biomedical subjects
Publications and source records attributed to W A Ayer.
Two 3(2H)-benzofuranones and three chromanes were isolated from the mycoparasitic fungus Coniothyrium minitans. Their structures and absolute stereochemistry were determined by spectroscopic methods.
The structures of four alkaloids extracted from Lycopodium lucidulum (Lycopodiaceae) were established by X-ray and 2D NMR spectroscopic analyses. The dihydro-derivative of oxolucidine A, which was obtained by NaBH4 reduction of oxolucidine A, was treated with p-bromobenzoyl chloride to afford crystals, whose X-ray crystallographic analysis established the stereostructure, including the absolute configuration. The 2D NMR spectra of tetrahydrodeoxylucidine B were fully analyzed to establish the full structure of lucidine B, and the hitherto unknown stereochemistry at the C-14 position was established as beta-H. The structure of a new alkaloid, lucidulinone, was determined by spectroscopic analysis to be luciduline lactam.
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Although the actual occasions for doing so may be infrequent, it is important that the dentist be aware of how to make referrals for psychological reasons.
Chemical investigation of the metabolites produced when a new fungus, Hyphozyma lignicola, isolated from blackgalls on aspen, was grown in malt extract liquid medium resulted in the isolation and identification of five trehalose esters 1-5, which are unusual fungal metabolites. The major compound is 3,6-di-O-acetyl-2-O-octadecanoyl-alpha,alpha-D-trehalose [2]. The structures were established by the analysis of nmr and fabms data in combination with chemical degradation.
The metabolites of the Canadian tuckahoe, the sclerotium of Polyporus tuberaster, have been investigated. The ten-membered lactone tuckolide [1] was isolated, and its structure was determined by spectroscopic methods and confirmed by X-ray crystallography. Ergosterol, ergosterol peroxide, and several unidentified ergosterol derivatives were also obtained, along with an unidentified disaccharide.
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The binding of [14,15-3H]14,15-dihydroforskolin ([3H]DHF) to rat liver membranes has been further characterized and was compared with the stimulatory effect of forskolin on adenylate cyclase. The binding equilibrium dissociation constant (KD) for 14,15-dihydroforskolin obtained in inhibition experiments was 0.6 microM, with a maximal binding capacity (Bmax) of 114 pmol/mg protein. A similar KD value (0.5 microM) was derived from kinetics studies that revealed very rapid association and dissociation reactions. For structure-activity relationship studies several forskolin derivatives were synthesized and tested for their ability to inhibit [3H]DHF binding and increase adenylate cyclase activity. Among the tested compounds, forskolin itself was the most potent agonist (K1 = 0.2 microM). Further modification of the molecule in position 7 and (or) 1 decreased or abolished its agonist properties in both adenylate cyclase and binding studies. [3H]DHF binding was not affected by several nucleotides, carbohydrates, lectins, and hormone receptor agonists including isoproterenol, glucagon, and adenosine, but the steroids 17-beta-estradiol, progesterone, and testosterone showed slight inhibitory effects at unphysiologically high concentrations. [3H]DHF binding and forskolin-stimulated adenylate cyclase were sensitive to heat and N-ethylmaleimide treatment. Forskolin protected adenylate cyclase against inactivation by heat but not by N-ethylmaleimide. Preincubation of the membrane with trypsin decreased [3H]DHF binding. The results presented in this study demonstrate that the binding sites identified with [3H]DHF have a high specificity for forskolin and provide evidence that these binding sites are involved in the stimulation of adenylate cyclase by forskolin.
A total of 484 clinical abnormalities were observed in 7,041 dentists who participated in head, neck, and oral examinations during a 7-year period. Most of the dentists had been unaware of the lesions. Forty-nine of the 97 dentists who were informed that they had potentially serious lesions sought further diagnostic assistance. Of the suspected carcinomas, six were confirmed as basal cell carcinomas and one was confirmed as a mucoepidermoid carcinoma of the palate. The results of the examination substantiate the recommendation that dentists undergo, as well as administer to patients, periodic and thorough head, neck, and oral examinations.
Dentists participating in a health screening at the 1984 annual session completed a brief questionnaire concerning patient turnover. In most dentists' opinions, patients more frequently leave a practice for reasons independent of the practice: they change residences and jobs. Patients' dissatisfaction with how they are treated, with the quality of care, and with pain and anxiety control also are believed to be among the factors "pushing" away patients. Lay referral is the major source of new patients, together with general community reputation and practice location.
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Dentists participating in a health screening at the 1983 ADA annual session were asked to complete a brief questionnaire concerning their attitudes and methods of managing anxious patients. Most dentists see patient fear as an extremely important dimension of their practice and believe it to be the most important impediment to patient satisfaction. Behavioral methods such as "talking" appear to be the most frequently used methods of dealing with fearful patients. Finally, most dentists appear to learn their behavioral management methods through informal means.