血液与非血液灌流行缺血预处理鼠心的电生理实验研究

本实验研究血液与非血液灌流条件下缺血预处理（ＩＰ）对心肌的保护作用。应用离体大鼠Ｌａｎｇｅｎｄｏｒｆ灌流模型，分血液灌流ＩＰ组、非血液（ＫｒｅｂｓＨｅｎｓｅｌｅｉｔ液，ＫＨ液）灌流ＩＰ组及相应的对照组。测量心肌电生理特性等指标。结果与ＫＨ液灌流心脏相似，用血液灌流的大鼠心脏经ＩＰ后，在随后的停灌和复灌期间，心室颤动阈升高，心律失常发生率明显降低。实验结论为在用血液灌流离体大鼠心脏模型上，ＩＰ对心肌的保护作用与用生理溶液灌流的模型基本相同。     

Ultra wide field fundus biomicroscopy with the Volk Quadraspheric lens

Fundus biomicroscopy as a clinical technique has been enhanced significantly by the addition of indirect view condensing lenses. The combination of this type of lens with a corneal contact element allows higher power and better stability so that a wider field can be obtained. The Panfunduscope of Schlegel and the Mainster retinal lens are examples of this design that have been successfully applied to both examination and to pan-retinal photocoagulation. Volk has recently introduced a new aspheric design indirect contact lens system which is higher in power and provides a wider field of view (125 degrees) than previously obtainable. This article describes the optical properties and use of the Quadraspheric lens.     

FEASIBILITY OF CONDUCTING CARDIOVASCULAR OUTCOME RESEARCH IN AUSTRALIAN GENERAL PRACTICE: RESULTS FROM THE ANBP2 PILOT STUDY

1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.     

Comparison of energy expenditure estimated in healthy infants using the doubly labelled water and energy balance methods

The doubly labelled water method was used to estimate energy expenditure in 20 formula-fed infants (10 aged 1 month and 10 aged 4 months). We then compared the energy expenditure values with energy balance values calculated from energy intake and energy cost of growth. Our purpose was to compare various published equations for calculating CO2 expiration rates (and thus energy expenditure values) from the isotopic data. Those equations in which we used measured values for 18O and 2H isotope dilution spaces and estimated or measured values for insensible water losses yielded energy expenditure values (69.7 +/- 8.4 kcal/kg/d) that agreed most closely with energy balance data (70.3 +/- 11.9 kcal/kg/d). Equations in which we used a constant ratio of 1.03 between the 2H and 18O isotope dilution spaces resulted in energy expenditure values (66.3 +/- 10.2 kcal/kg/d) lower than those predicted by the energy balance data. Data analysis by nonlinear curve fitting compared to logarithmic transformation did not alter the estimates of energy expenditure obtained in these infants.     

Historical perspective of optometrists' and other health professionals' involvement in hospitals

For a number of years, optometrists have had informal working and referral relationships with many hospitals. Many hospitals were requesting diagnostic and treatment services from community optometrists while many optometrists were also requesting official recognition. With changes in the medical staff standard of the Joint Commission on Accreditation of Hospitals (JCAH)a that allowed independently licensed practitioners to be on staff, a number of optometrists have been requesting clinical privileges and to be on the Medical Staff. Practicing in a hospital can augment one's practice and can allow the optometrist greater opportunities to interact with other professionals and utilize the hospital's diagnostic facilities.     

Contact angles of substances used for internal tamponade in retinal detachment surgery

In order to ascertain the tamponade effect of air and silicone oil we examined the contact angles subtended by ex vivo human retina, Teflon and Perspex to find a suitable experimental material which would mimic the surface properties of the retina at a three-phase interface. Using the captive bubble technique to measure the contact angle, it was found that air subtended a larger contact angle (38.8°) with the retina than did silicone oil (18.2°). On coating the Perspex surface with protein (PCP), it was observed that the surface properties were modified such that PCP subtended contact angles with air (43.0°) and silicone oil (16.4°) similar to those subtended by ex vivo human retina. Using PCP as an experimental material that mimics ex vivo human retina, spherical chambers were employed in order to examine qualitatively and to quantify the arc of contact obtained with air and silicone oil. It was found that air gave a greater arc of contact for the same percentage fill than silicone oil.     

Peak velocities of visually and nonvisually guided saccades in smooth-pursuit and saccadic tasks

 Smooth pursuit typically includes corrective catch-up saccades, but may also include such intrusive saccades away from the target as anticipatory or large overshooting saccades. We sought to differentiate catch-up from anticipatory and overshooting saccades by their peak velocities, to see whether the higher velocities of visually rather than nonvisually guided saccades in saccadic tasks may be found also in saccades in pursuit. In experiment 1, 12 subjects showed catch-up, anticipatory, and overshooting saccades to comprise 70.4% of all saccades in pursuit of periodic, 30°/s constant-velocity targets. Catch-up saccades were faster than the others. Saccadic tasks were run as well, on 19 subjects, including the 12 whose pursuit data were analyzed, with target-onset, target-remaining (saccade to the remaining target when the other three extinguish), and antisaccade tasks. For 17 of the 19 subjects, antisaccade velocities were lower than for either target-onset or target-remaining tasks. Velocities for the target-remaining task were near those for target onset, indicating that target presence, not its onset, defines visually guided saccades. Error and reaction-time data suggest greater cognitive difficulty for target remaining than for target onset, so that the cognitive difficulty of typical nonvisually guided saccade tasks is not sufficient to produce their lowered velocity. To produce reliably, in each subject, catch-up and anticipatory saccades with comparable amplitude distributions, nine new subjects were asked in experiment 2 to make intentional catch-up and anticipatory saccades in pursuit, and were presented with embedded target jumps to elicit catch-up saccades, all with periodic target trajectories of 15°/s and 30°/s. Velocities of intentional anticipatory saccades were lower than velocities of intentional catch-up saccades, while velocities of intentional and embedded catch-up saccades were similar. Target-onset and remembered-target saccadic tasks were run, showing the expected higher velocity for the target-onset task in each subject. Both experiments demonstrate higher peak velocities for catch-up saccades than for anticipatory saccades, suggesting that cortical structures preferentially involved in nonvisually guided saccades may initiate the anticipatory and overshooting saccades in pursuit. Received: 1 December 1995 / Accepted: 25 February 1997