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Biomedical subjects

C A Burgess

Publications and source records attributed to C A Burgess.

12 recordsLinked to original sources
PubMed1999

Brief modification of suggestibility and hypnotic analgesia: too good to be true?

A 10-minute training procedure, based on the Carleton Skill Training Program, has previously been reported to produce substantial increments in responsiveness to hypnotic suggestion. The authors attempted to replicate this effect and also assessed the impact of the training procedure on hypnotically suggested analgesia. Ninety-eight students who had been preselected for high, medium, and low levels of initial suggestibility were randomly assigned to experimental and control groups. Training failed to increase overall suggestibility scores or to enhance the effects of a suggestion for pain reduction. Suggested pain reduction was more highly correlated with posttreatment suggestibility scores than with pretreatment suggestibility and, in a regression analysis, only posttreatment suggestibility predicted pain reduction uniquely.

Female↗
PubMed1999

Attentional resources in hypnotic responding.

Theories of hypnotic responding differ regarding attentional processes. Predictions derived from neodissociation, dissociation control, response set, and ironic process theory were tested by administering suggestions with and without cognitive load to high suggestible participants and low suggestible simulators. Cognitive load interfered with responses to ideomotor and cognitive suggestions but not with responses to challenge suggestions. The effect of cognitive load on suggested amnesia depended on the assessment of that response. Although cognitive load decreased recall on the amnesia trial, it did so even more on recall trials before the amnesia suggestion was given and after it was canceled. These data indicate that attentional effort is required for both recall and memory suppression. Under conditions of low cognitive load, simulators displayed less recall than did nonsimulating participants during suggested amnesia, and they reported smaller subjective responses to ideomotor and challenge suggestions.

Adult↗
PubMed1994

Past-life identities, UFO abductions, and satanic ritual abuse: the social construction of memories.

People sometimes fantasize entire complex scenarios and later define these experiences as memories of actual events rather than as imaginings. This article examines research associated with three such phenomena: past-life experiences, UFO alien contact and abduction, and memory reports of childhood ritual satanic abuse. In each case, elicitation of the fantasy events is frequently associated with hypnotic procedures and structured interviews which provide strong and repeated demands for the requisite experiences, and which then legitimate the experiences as "real memories." Research associated with these phenomena supports the hypothesis that recall is reconstructive and organized in terms of current expectations and beliefs.

Adolescent↗
PubMed1992

Hypnosis, reporting bias, and suggested negative hallucinations.

We examined the role of reporting bias in hypnotic negative hallucinations by using a paradigm in which reporting bias was assessed independently of perceptual change. In Experiment 1, highly hypnotizable subjects reported significant loudness reductions when tested for hypnotic deafness. Later, however, these subjects biased their reported loudness reductions in the absence of perceptual change, and their reporting bias scores were almost as large as their hypnotic deafness reports. Subjects also biased their ratings of strategy use. In Experiment 2, ratings of blindness given in response to a hypnotic negative visual hallucination suggestion were significantly correlated with reporting bias scores obtained in this paradigm. Although hypnotic blindness and hypnotic deafness correlated significantly, the partial correlation between these variables was nonsignificant when reporting bias scores were statistically controlled. Theoretical implications are discussed.

Adult↗
PubMed1992

Systemic hypertension and senile cataracts: an epidemiologic study.

A hospital-based case-control study was conducted at the Allen Park Michigan Veterans Administration Medical Center to determine whether a diagnosis of systemic hypertension was associated with increased risk for senile cataracts. Data from 136 cataract extraction patients were compared to 142 controls. Systemic hypertension was found to increase significantly the risk for posterior subcapsular cataracts. Diabetes mellitus was also associated with increased cataract risk. The use of nonsteroidal anti-inflammatory agents showed a significant protective effect only in the presence of a diagnosis of systemic hypertension.

Aged↗
PubMed1990

Assembly of dimeric myeloperoxidase during posttranslational maturation in human leukemic HL-60 cells.

Myeloperoxidase is a major protein component of the azurophilic granules (specialized lysosomes) of normal human neutrophils and serves as part of a potent bactericidal system in the host defense function of these cells. In normal, mature cells, myeloperoxidase occurs exclusively as a dimer of Mr 150,000 while in immature leukemia cells, there are both monomeric (Mr 80,000) as well as dimeric species. Like other lysosomal enzymes, myeloperoxidase is synthesized as a larger glycosylated precursor (Mr 91,000) that undergoes processing through single-chain intermediates (Mr 81,000 and 74,000) to yield mature heavy (Mr 60,000) and light (Mr 15,000) subunits. To study the assembly of dimeric myeloperoxidase, azurophilic granules were isolated from either unlabeled or pulse-labeled ([35S]methionine/cysteine) HL-60 cells, and myeloperoxidase was extracted and separated into monomeric and dimeric forms by FPLC gel filtration chromatography. Steady-state levels of dimeric and monomeric myeloperoxidase were found to account for 67% and 33%, respectively, of the total peroxidase activity and were correlated with the levels of associated heme as measured by absorption at 430 nm. Labeled myeloperoxidase polypeptides were immunoprecipitated using a monospecific rabbit antibody and were identified and quantitated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis/fluorography and liquid scintillation counting. After a 2-h pulse, labeled myeloperoxidase species of Mr 74,000 and 60,000 were found in fractions coeluting with the monomeric form of myeloperoxidase.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, High Pressure Liquid↗
PubMed1990

Leukotriene B4 increases pulmonary transvascular filtration by a neutrophil-independent mechanism.

We examined the role of circulating granulocytes in the pulmonary microvascular response to leukotriene B4 (LTB4) by prior depletion of circulating granulocytes using hydroxyurea. LTB4 (2 micrograms/kg injection followed by infusion of 2 micrograms/kg over 15 min) produced transient increases in pulmonary arterial pressure and pulmonary vascular resistance, indicating that neutrophils were not required for the pulmonary hemodynamic effects of LTB4. Infusion of LTB4 in granulocyte-depleted sheep also resulted in transient increases in pulmonary lymph flow (QL) with no significant change in the lymph-to-plasma protein concentration ratio (L/P), findings similar to those in control animals. In vitro studies indicated that LTB4 (10(-7) or 10(-9) M) produced a transient adherence of neutrophils to cultured pulmonary artery endothelial monolayers. Maximal responses occurred at 10 min after the addition of LTB4 to the endothelial cell-neutrophil coculture system, and the adherence decreased to base line within 60 min. LTB4 infusion in sheep also produced a transient uptake of autologous 111In-oxine-labeled neutrophils. The results indicate that LTB4-mediated increase in pulmonary transvascular protein clearance (QL x L/P) is independent of circulating granulocytes.

Animals↗
PubMed1988

Pulmonary microvascular response to LTB4: effects of perfusate composition.

We examined the effects of leukotriene B4 (LTB4) on pulmonary hemodynamics and vascular permeability using isolated perfused guinea pig lungs and cultured monolayers of pulmonary arterial endothelial cells. In lungs perfused with Ringer solution, containing 0.5 g/100 ml albumin (R-alb), LTB4 (4 micrograms) transiently increased pulmonary arterial pressure (Ppa) and capillary pressure (Pcap). Pulmonary edema developed within 70 min after LTB4 injection despite a normal Pcap. The LTB4 metabolite, 20-COOH-LTB4 (4 micrograms), did not induce hemodynamic and lung weight changes. In lungs perfused with autologous blood hematocrit = 12 +/- 1%; protein concentration = 1.5 +/- 0.2 g/100 ml), the increases in Ppa and Pcap were greater, and both pressures remained elevated. The lung weight did not increase in blood-perfused lungs. In lungs perfused with R-alb (1.5 g/100 ml albumin) to match the blood perfusate protein concentration, LTB4 induced similar hemodynamic changes as R-alb (0.5 g/100 ml) perfusate, but the additional albumin prevented the pulmonary edema. LTB4 (10(-11)-10(-6) M) with or without the addition of neutrophils to the monolayer did not increase endothelial 125I-albumin permeability. Therefore LTB4 induces pulmonary edema when the perfusate contains a low albumin concentration, but increasing the albumin concentration or adding blood cells prevents the edema. The edema is not due to increased endothelial permeability to protein and is independent of hemodynamic alterations. Protection at higher protein-concentration may be the result of LTB4 binding to albumin.

Animals↗