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Biomedical subjects

G Maynard

Publications and source records attributed to G Maynard.

10 recordsLinked to original sources
PubMed2005

Absolute time-resolved x-ray laser gain measurement.

We present the first direct measurement of the time evolution of the gain of a soft x-ray laser amplifier. The measurement is based on the injection of a seed pulse, obtained by high-order harmonic generation, into an x-ray laser medium. Strong amplification occurs when the seed pulse is synchronized with the gain period. By precisely varying the delay between the x-ray laser plasma creation and the seed pulse injection, the actual temporal evolution of the soft x-ray amplifier gain is obtained with a subpicosecond resolution.

Journal Article↗
PubMed1998

A role for histamine and substance P in immediate allergic responses in guinea pig airways: characterization of MDL 108,207DA, a dual H1/NK-1 receptor antagonist.

BACKGROUND: Histamine is a critical mediator of immediate hypersensitivity reactions. Sensory neuropeptides, such as substance P (SP), may also contribute to acute inflammatory responses. A compound which antagonizes both H1 and NK-1 receptors, such as MDL 108,207DA, may present a significant therapeutic advantage over pure antihistamines. METHODS: The binding affinity of MDL 108,207DA for H1 and NK-1 receptors was evaluated and its potency of antagonism evaluated in vitro. The in vivo antagonism of SP- or histamine-induced microvascular leakage in guinea pig airways was examined. A role for these mediators in antigen-induced microvascular leakage in ovalbumin-sensitized guinea pig airways was examined using MDL 108,207DA as well as the NK-1-selective antagonist FK888 and the H1-selective antagonist pyrilamine alone or in combination. RESULTS: The affinity of MDL 108,207DA for H1 and NK-1 receptors is similar to that of receptor-selective antagonists. The compound inhibits both receptors in vitro and in vivo with comparable potencies for each. The efficacy of FK888 in combination with pyrilamine and MDL 108,207DA on antigen-induced microvascular leakage in sensitized guinea pig airways supports a role for both SP and histamine in early allergic responses. CONCLUSION: The contribution of both SP and histamine to immediate hypersensitivity reactions supports the utility of NK-1 and H1 receptor antagonist therapy. MDL 108,207DA incorporates both activities into the same compound and, as a result, may be useful in the treatment of allergic diseases.

Animals↗
PubMed1995

Medical staff consolidation issues and concerns.

In the past decade there have been increases in health care consolidations. While the literature on hospital mergers is abundant, there is little on mergers of medical staffs. In this study, we interviewed senior administrators in 22 midwestern medical institutions that had consolidated between 1987 and 1990. Our study is an exploration of topics of concern that administrators have encountered during processes of medical staff consolidation. Administrators stated that the medical staff was most concerned about relationships with nursing and support staff, "turf" issues, and a sense of loss. They recommended that increased attention be paid to specific local issues and that there be active involvement and communication between medical staff and administrators at all phases of the consolidation process.

Communication↗
PubMed1981

Philophthalmus gralli: chemosensitivity of miracidia.

The responses of Philophthalmus gralli miracidia to various chemicals stimulative to other miracidial species were tested by contact and return (CR) to agar blocks containing chemicals and aggregation near a point inoculum in phi-chambers. Of a series of amino acids, glutamic and aspartic acid elicited the greatest responses in both tests, which were similar to that observed with snail-conditioned water. Sialic, acetic, hydrochloric, and sulfuric acids gave high percent CR at all concentrations tested but required higher levels to stimulate a significant miracidial response in phi-chambers. Miracidia were slightly responsive to Mg++ and ammonia in CR tests but only showed a significant reaction to 1.0 mM ammonia in phi-chambers. Attachment responses to the agar blocks by miracidia were noted at the higher concentrations of all chemicals tested except MgSO4 and NH4Cl. At 25 and 50 mM H2SO4 and HCl, contact with the agar block proved lethal to the miracidia. Miracidial behavior was klinokinetic rather than chemotactic in both test systems.

Amino Acids↗