The Leicester semi-automated olfactory threshold test--a psychophysical olfactory test for the 21st century.

Objective: Develop a useful and cost-effective olfactometer for routine clinical use by providing a standardised threshold test for patients with olfactory disorders presenting in the ENT clinic.

Method Of Study: A prospective study of olfactory thresholds in 48 healthy volunteers on 2 consecutive occasions, undergoing quantitative testing with an olfactometer. Further studies of 10 subjects performing 20 tests and 100 subjects performing a single test were performed.

Does odour cross contamination alter olfactory thresholds in certain odours?

Objectives: To determine if 1) there is cross contamination between odours tested on thresholds achieved, 2) a delay period is necessary between testing different odours.

Methods: Thirty-five subjects underwent threshold testing with phenethyl alcohol (PEA), ethylmercaptan (MER), acetic acid (ACE), and eucalyptol (EUC) using serial logarithmic dilutions. On separate occasions subjects were exposed to high concentrations of PEA, ACE and EUC in random order for two minutes, and thresholds for all four odours re-tested.

The superosmic phenomenon.

Background: Olfaction studies in the institution of Department of Otorhinolaryngology at Leicester Royal Infirmary have detected a previously unreported, variable phenomenon--'superosmia'--in which subjects' olfaction threshold concentrations are up to 100,000 smaller than the average value.

Objectives: The aim of this report is to define and quantify this phenomenon.

Methods: Two hundred and thirty subjects, who had been screened for active nasal pathology (age range 20-60 years), underwent individual olfactory threshold tests for phenylethyl alcohol or eucalyptol, using a computer-driven olfactometer in a controlled laboratory setting.

Olfactory clearance: what time is needed in clinical practice?

Objective: To determine olfactory adaptation and clearance times for healthy individuals, and to assess the effect of common variables upon these parameters.

Study Design And Setting: Fourteen healthy volunteers were recruited for a series of tests. Their initial olfactory threshold levels for phenethyl alcohol were determined.

Rational conversion of substrate and product specificity in a Salvia monoterpene synthase: structural insights into the evolution of terpene synthase function.

Terpene synthases are responsible for the biosynthesis of the complex chemical defense arsenal of plants and microorganisms. How do these enzymes, which all appear to share a common terpene synthase fold, specify the many different products made almost entirely from one of only three substrates? Elucidation of the structure of 1,8-cineole synthase from Salvia fruticosa (Sf-CinS1) combined with analysis of functional and phylogenetic relationships of enzymes within Salvia species identified active-site residues responsible for product specificity. Thus, Sf-CinS1 was successfully converted to a sabinene synthase with a minimum number of rationally predicted substitutions, while identification of the Asn side chain essential for water activation introduced 1,8-cineole and alpha-terpineol activity to Salvia pomifera sabinene synthase.