Biomedical subjects

J D Ryan

Publications and source records attributed to J D Ryan.

3 recordsLinked to original sources

PubMed2003

Propofol target-controlled infusions for sedation--a safe technique for the non-anaesthetist?

OBJECTIVE: As an alternative to general anaesthesia for dentistry.attention has been focused on other, apparently safer, methods of pain and anxiety control. We have undertaken a study to evaluate the safety and efficacy of intravenous sedation using propofol target-controlled infusions. DESIGN: We describe a retrospective observational analysis of propofol conscious sedation as an adjunct to local anaesthesia for patients undergoing simple or surgical exodontia. All the patients were assessed,selected and treated according to standardized hospital sedation protocols. Experienced anaesthetists used a standard regimen, with ECG, pulse oximetry and non-invasive blood pressure monitoring. A standard sedation record was completed for each patient. The initial target plasma propofol concentration was set at 1.5 microg ml(-1), adjusted thereafter to achieve the desired level of sedation. Any adverse events were recorded. SETTING: Birmingham Dental Hospital. SUBJECTS: Three hundred consecutive sedation episodes in adult dental phobic patients requiring exodontia under local anaesthesia. RESULTS: Sedation and treatment were satisfactorily completed in 297 patients. The mean target propofol concentration required was 2.1 microg ml(-1), (SD = 0.47 microg ml(-1), range 1 - 4 microg ml(-1)). General anaesthesia occurred in two cases (target concentration (TC) 2 microg ml(-1)), over sedation in 11 cases(TC 1 - 3 microg ml(-1)), and transient hypoxaemia in 7 cases (TC 1.8 - 2.5 microg ml(-1)). CONCLUSION: Intravenous sedation with target-controlled propofol infusions is effective. However, significant adverse effects may occur at target concentrations below 2.1 microg ml(-1). Only anaesthetists working in an appropriate environment should practise this technique.

Adolescent↗

PubMed2000

Amnesia is a deficit in relational memory.

Eye movements were monitored to assess memory for scenes indirectly (implicitly). Two eye movement-based memory phenomena were observed: (a) the repetition effect, a decrease in sampling of previously viewed scenes compared with new scenes, reflecting memory for those scenes, and (b) the relational manipulation effect, an increase in viewing of the regions where manipulations of relations among scene elements had occurred. In normal control subjects, the relational manipulation effect was expressed only in the absence of explicit awareness of the scene manipulations. Thus, memory representations of scenes contain information about relations among elements of the scenes, at least some of which is not accessible to verbal report. But amnesic patients with severe memory impairment failed to show the relational manipulation effect. Their failure to show any demonstrable memory for relations among the constituent elements of scenes suggests that amnesia involves a fundamental deficit in relational (declarative) memory processing.

Adult↗

PubMed1990

Determination of the degree of methyl esterification of pectins in small samples by selective reduction of esterified galacturonic acid to galactose.

A procedure for the determination of the degree of methyl esterification of pectin in virtually any sample is described. Samples were dissolved or suspended in 1 M imidazole buffer, pH 7.0, cooled on ice, and reduced with sodium borohydride. Quantitative reduction of samples was accomplished after 1 h using at least 20 mg sodium borohydride/mg sample. The degree of methyl esterification was determined by either the increase in galactose content as determined by GLC of the sugar or by the change in galacturonic acid content by colorimetric uronic acid analyses. Sample requirements were at least as low as 100 micrograms per determination by GLC or 2 to 3 mg per determination by colorimetric uronic acid analysis compared to 5 mg or more per determination for other published procedures. The degrees of methyl esterification determined by the methods described have compared very favorably with those determined by established methods.

Chromatography, Gas↗