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Biomedical subjects

R R Holt

Publications and source records attributed to R R Holt.

At least 19 recordsLinked to original sources
PubMed2001

Chocolate procyanidins decrease the leukotriene-prostacyclin ratio in humans and human aortic endothelial cells.

BACKGROUND: Polyphenolic phytochemicals inhibit vascular and inflammatory processes that contribute to disease. These effects are hypothesized to result from polyphenol-mediated alterations in cellular eicosanoid synthesis. OBJECTIVE: The objective was to determine and compare the ability of cocoa procyanidins to alter eicosanoid synthesis in human subjects and cultured human aortic endothelial cells. DESIGN: After an overnight fast, 10 healthy subjects (4 men and 6 women) consumed 37 g low-procyanidin (0.09 mg/g) and high-procyanidin (4.0 mg/g) chocolate; the treatments were separated by 1 wk. The investigation had a randomized, blinded, crossover design. Plasma samples were collected before treatment and 2 and 6 h after treatment. Eicosanoids were quantitated by enzyme immunoassay. Endothelial cells were treated in vitro with procyanidins to determine whether the effects of procyanidin in vivo were associated with procyanidin-induced alterations in endothelial cell eicosanoid synthesis. RESULTS: Relative to the effects of the low-procyanidin chocolate, high-procyanidin chocolate induced increases in plasma prostacyclin (32%; P<0.05) and decreases in plasma leukotrienes (29%; P<0.04). After the in vitro procyanidin treatments, aortic endothelial cells synthesized twice as much 6-keto-prostaglandin F(1alpha) (P<0.01) and 16% less leukotriene (P<0.05) as did control cells. The in vitro and in vivo effects of procyanidins on plasma leukotriene-prostacyclin ratios in culture medium were also comparable: decreases of 58% and 52%, respectively. CONCLUSION: Data from this short-term investigation support the concept that certain food-derived flavonoids can favorably alter eicosanoid synthesis in humans, providing a plausible hypothesis for a mechanism by which they can decrease platelet activation in humans.

Adult↗
PubMed2000

Epicatechin in human plasma: in vivo determination and effect of chocolate consumption on plasma oxidation status.

Diets that are rich in plant foods have been associated with a decreased risk for specific disease processes and certain chronic diseases. In addition to essential macronutrients and micronutrients, the flavonoids in a variety of plant foods may have health-enhancing properties. Chocolate is a food that is known to be rich in the flavan-3-ol epicatechin and procyanidin oligomers. However, the bioavailability and the biological effects of the chocolate flavonoids are poorly understood. To begin to address these issues, we developed a method based on HPLC coupled with electrochemical (coulometric) detection to determine the physiological levels of epicatechin, catechin and epicatechin dimers. This method allows for the determination of 20 pg (69 fmol) of epicatechin, which translates to plasma concentrations as low as 1 nmol/L. We next evaluated the absorption of epicatechin, from an 80-g semisweet chocolate (procyanidin-rich chocolate) bolus. By 2 h after ingestion, there was a 12-fold increase in plasma epicatechin, from 22 to 257 nmol/L (P < 0.01). Consistent with the antioxidant properties of epicatechin, within the same 2-h period, there was a significant increase of 31% in plasma total antioxidant capacity (P < 0.04) and a decrease of 40% in plasma 2-thiobarbituric acid reactive substances (P < 0.01). Plasma epicatechin and plasma antioxidant capacity approached baseline values by 6 h after ingestion. These results show that it is possible to determine basal levels of epicatechin in plasma. The data support the concept that the consumption of chocolate can result in significant increases in plasma epicatechin concentrations and decreases in plasma baseline oxidation products.

Adult↗
PubMed2000

A dose-response effect from chocolate consumption on plasma epicatechin and oxidative damage.

Evidence from epidemiological studies suggests that a diet high in plant foods and rich in polyphenols is inversely associated with a risk for cardiovascular and other chronic diseases. Chocolate, like red wine and green tea, is a polyphenol-rich food, primarily containing procyanidin polyphenols. These polyphenols are hypothesized to provide cardioprotective effects due to their ability to scavenge free radicals and inhibit lipid oxidation. Herein, we demonstrate that 2 h after the ingestion of a procyanidin-rich chocolate containing 5.3 mg total procyanidin/g, of which 1.3 mg/g was (-)-epicatechin (epicatechin), plasma levels of epicatechin increased 133 +/- 27, 258 +/- 29 and 355 +/- 49 nmol/L in individuals who consumed 27, 53 and 80 g of chocolate, respectively. That the rise in plasma epicatechin levels was functionally significant is suggested by observations of trends for dose-response increases in the plasma antioxidant capacity and decreases in plasma lipid oxidation products. The above data support the theories that in healthy adults, 1) a positive relationship exists between procyanidin consumption and plasma procyanidin concentration and 2) the rise in plasma epicatechin contributes to the ability of plasma to scavenge free radicals and to inhibit lipid peroxidation.

Adult↗
PubMed2000

Ground reaction force after a sideways push as a measure of balance in recovery from stroke.

OBJECTIVE: To investigate if measuring ground reaction force after a sideways push at the hips gives a measure of standing balance in stroke subjects. METHODS: Fifteen control subjects and 13 right hemiparetic subjects who were able to stand independently stood with their feet on a single forceplate. Horizontal sideways pushes of 3% body weight were delivered to each side of the pelvis with the subjects held firmly in a semi-rigid belt. Measurements were made of lateral pelvic displacement (sway) and the lateral sheer component of ground reaction force (GRF). RESULTS: Right hemiparetic subjects showed significantly greater sway after a sideways push (p < 0.01) and later onset of GRF (p < 0.01) when pushed to their weak side compared with control subjects. There was also a positive correlation between sway after a sideways push and the onset latency of GRF in both strokes (0.41) and controls (0.61). The hemiparetic subjects swayed more (p < 0.01) when pushed to their weak side compared with their stronger side and their GRF latency was longer, but this latter measurement failed to reach statistical significance. No difference was seen between sides in sway or GRF latency in controls. CONCLUSIONS: The latency of GRF onset after a push at the hips in controls and in stroke subjects is related to sway and both measurements increase after a stroke. This test offers a method of measuring balance after a stroke, and serial testing of an individual after a stroke may prove a useful measure of an individual's recovery of balance.

Adolescent↗
PubMed1987

Effects of modified instructions on the Washington University Sentence Completion Test of Ego Development.

This research project was designed to investigate the possibility that asking subjects to respond in a mature manner when they take the Washington University Sentence Completion Test of Ego Development (WUSCTED) would result in higher test scores and improve the test-retest reliability of the measure. The results showed that there was a significant increase in Total Protocol Ratings (TPRs) and item sums in the experimental group (n = 32) over the control group (n = 32). In addition, the experimental group spent more time and used significantly more words in its response than did the control group. The question of improved test-retest reliability remains only tentatively resolved. The item sum scores showed a significantly higher correlation for the experimental instruction than for the control, although the test-retest agreement between TPR levels was insignificantly different in the two instructional groups.

Adolescent↗
PubMed1986

The development of primary process in children's Rorschachs.

Three cohorts of normal Italian schoolchildren, 55 boys and 47 girls, were given Rorschachs at ages 6, 7, and 8; 9, 10, and 11; and 12 and 13. Regardless of sex or score, primary process (scored by Holt's method) tends to diminish with age; but significantly among the boys only for the sums of all primary process, of Level 2 responses, and of content. Measures of control showed similar developmental trends, mean form level advancing significantly in the total sample and among girls. Even stronger trends within cohorts were confounded by retest effects.

Adolescent↗
PubMed1986

Clinical and statistical prediction: a retrospective and would-be integrative perspective.

One of the early participants in the clinical-statistical controversy describes his effort to mediate the dispute and to direct attention to the underlying issues, to most of which the box scores were irrelevant. A previously undiscussed undercurrent of the controversy is the conflict between different metaphysical world views, the history of which for the past few hundred years is quickly sketched. The mechanist metaphysics of behaviorism, which has long been dominant in American mainstream psychology, favors objective and statistical approaches and discourages interest in judgement, an issue that nevertheless refuses to go away. Systems philosophy is proposed as an integrative alternative.

Behaviorism↗
PubMed1975

Symposium on The Ego and the Id after fifty years. The past and future of ego psychology.

Having six roots in ordinary observation and introspection, ego psychology has a long pre-Freudian history, which influenced Freud's first usages of Ich. His works before 1923 contain much that is substantively ego psychology; The Ego and the Id was not a paradigm change but a consolidation of pre-existing ideas. The structural theory replaced a model (topographic) which Freud actually used very little, especially clinically, and he failed to remedy its gravest methodological faults. The ego-id model is an integral part of metapsychology, and will pass out of use as the latter dies, with no detriment to clinical psychoanalysis.

Cognition↗