Biomedical subjects

D Evert

Publications and source records attributed to D Evert.

6 recordsLinked to original sources

PubMed1998

[The effect of a two-week anti-orthostatic hypokinesia on the cardiac function and on the latter's regulation in monkeys].

Investigated were the effects of 2-week exposure of four Macaca mulattas to the head-end tilted downward at 10 degrees on contractility of the left myocardium and its controls basing on the data of functional loading tests on the tilting table and at two regimes of centrifugation. The experiment included registration of the left heart pressure, volumetric blood flow in the aorta, and EKG in order to determine stroke volume, maximal isovolumetric pressure, end-systolic and end-diastolic pressures, maximal contraction and relaxation velocities, end-systolic myocardial elasticity, and a constant of the isovolumetric relaxation. As was stated, HDT does not impair contractility of the left myocardium; however, sensitivity of the HR baroreflex control wakens.

Animals↗

PubMed1996

Longimicins A-D: novel bioactive acetogenins from Asimina longifolia (annonaceae) and structure-activity relationships of asimicin type of annonaceous acetogenins.

Bioactivity-directed fractionation of the ethanol extract of Asimina longifolia led to the isolation of four novel bioactive annonaceous acetogenins: longimicins A-D (1-4). Compounds 1-4 represent the asimicin type of acetogenins; however, the locations of the adjacent bis-tetrahydrofuran (THF) ring moieties are shifted along the aliphatic chains compared to the known compounds of this type. They are the first examples among this type of acetogenins with the placements of the ring systems altered. Compounds 1-4 showed bioactivities in several bioassays, but they are less active than their structural isomers. Study of their structure-activity relationships (SAR) reveals that the position of the adjacent bis-THF ring moiety is essential for maximization of the bioactivities among these asimicin type annonaceous acetogenins.

Animals↗

PubMed1996

Longifolicin, longicoricin, and gigantetroneninone, three novel bioactive mono-tetrahydrofuran annonaceous acetogenins from Asimina longifolia (Annonaceae).

Longifolicin (1), longicoricin (2) and (2,4-cis and trans)-gigantetroneninone (3), three novel bioactive mono-tetra-hydrofuran (THF) gamma-lactone acetogenins, were isolated from the leaves and twigs of Asimina longifolia (Annonaceae) by directing the fractionation with the brine shrimp lethality test (BST). The structures were elucidated based on spectroscopic and chemical methods. Compounds 1-3 showed selective and potent cytotoxicities to certain human tumor cell lines.

Animals↗

PubMed1995

Precue effects in visual search: data or resource limited?

Precuing an observer as to where a target is more likely to occur in a subsequent visual array can increase the detectability (d') of a target at that location. This is often attributed to the observer's increased allocation of some limited cognitive resource ("attention") to the cued location. Two experiments are reported which are difficult to interpret in this way even though they involve similar cue effects. The first involves postcuing a location well after the array but before the observer responds, so that the cue can influence the response but not the observation. The second involves precuing, but with slow sequential presentation of array elements prior to the response, so the observer need not share any limited resource while processing each element in turn. Enhanced detectability similar to that produced with precues and simultaneous presentation of elements is shown to occur in each experiment. An alternative data-limited (rather than resource-limited) interpretation of these effects is provided by a mathematical model in which the observer integrates equally noisy or degraded internal representations of the array elements, but gives more weight to cued elements in selecting a response. Theoretical parameters of the model are shown to provide separate measures of both an observer's overall sensitivity and precue effects in cost-benefit analyses of cuing data.

Adult↗

PubMed1993

Healthcare foodservice report 1993. Getting ready for reform. Interview by Mitchell Schechter.

Hospital foodservice directors & dietitians are facing the greatest challenge of their careers -- to prepare, along with their institutions, for the most thoroughgoing reform of America's healthcare system ever proposed. Healthcare institutions across the country are seeking the means to offer enhanced patient services & gain competitive advantages by forming new alliances, new patient-centered care systems & cost-reduction programs. To aid in these efforts, their foodservices are developing comprehensive cross-training schemes, inter-departmental teams with other service groups & new ways to cut operating subsidies. Here's how five hospital foodservice departments are using cost controls, revenue building, quality management processes & enhanced efficiencies to help their institutions prepare for the changes ahead.

Cost Control↗

PubMedDate not supplied

[Heart functions in monkeys during a 2-week antiorthostatic hypokinesia].

Dynamics of the left heart ventricular muscle contractility and compliance was studied in 4 monkeys in the head down position (antiorthostatic hypokinesia) with the body angle 10 during 2 weeks. Functional tests on a tilt table and under two conditions of centrifuge rotation were performed prior to and after the antiorthostatic hypokinesia. No changes in the left heart ventricular muscle contractility was found. However, the sensitivity level of the baroreflex control decreased. Compliance of the left heart myocardial fibre increased in the first hours and days of the antiorthostatic hypokinesia.

Animals↗