Search PubMed⌕ Search

Biomedical subjects

B Wallace

Publications and source records attributed to B Wallace.

At least 73 records · Page 4Linked to original sources
PubMed1988

Surgical complications of thermal injury.

Aggressive control of intragastric pH in the burn patient has essentially eliminated upper gastrointestinal bleeding. The recent spectrum of complications in the thermally injured patient has shifted. Vascular occlusion and missed associated injury were the most frequent early complications in this review. Those complications occurring late in the course were attributed to sepsis originating in the burn wound. The common diagnostic error was to blame the burn injury for the patient's signs and symptoms. A high index of suspicion of an occult process must be exercised when caring for the burn patient who has burn shock with a decreasing hematocrit value or a compartment syndrome that does not respond to escharotomy or fasciotomy or the septic patient with a clean burn wound.

Adolescent↗
PubMed1988

Conditioning the behavior of Drosophila melanogaster by means of electric shocks.

Eighty male Drosophila melanogaster were observed individually for extended periods (1-2 hr) as they moved about in a small chamber consisting of a narrow, clear plastic ring whose vertical walls were thin epoxy plates with electric grids by means of which an 80-V shock could be delivered to the fly. Males (whether initially subjected to 0, 1, 2, or 3 electric shocks) that were observed for 10 consecutive 5-min sessions, given a supplemental electric shock (followed by a 2-min rest), and then observed for 5 additional 5-min sessions spent only 88.9% as much time on the grids after the supplemental shock as they had been spending earlier. This avoidance of the potentially electrified grids corresponds to that observed in tests involving the exposure of flies to 0, 1, 2, or 3 electric shocks preceding the 10 5-min sessions. The results reveal (i) an extreme variation in the normal behavior among unshocked (control) males and (ii) an exponential decline in the length of time spent on the grids immediately after receiving 1, 2, or 3 shocks. These data confirm earlier reports on the conditioning of behavior in Drosophila by means of electric shocks; in addition, they remove an ambiguity inherent in the earlier studies, which relied on a presumed exposure of each of 150 or more flies to each shock as it was delivered.

Animals↗
PubMed1988

Hypnotic susceptibility, visual distraction, and reports of Necker cube apparent reversals.

Subjects, either susceptible (n = 50) or resistant (n = 50) to hypnotic suggestion, were asked to report on frequency of apparent reversals (ARs) to the Necker cube illusion. Such reports were made in the presence or absence of various types of visual, geometric surrounds (squares, triangles, crosses, or parallelograms). In agreement with a number of previous experiments, susceptible subjects reported perceiving more ARs than did resistant subjects. This difference held whether visual surrounds were present or absent. The presence of surrounds did serve to reduce AR reports regardless of hypnotic susceptibility level. The results are examined in terms of the ability of subjects to selectively attend when confronted with potential visual distractors.

Attention↗
PubMed1988

Adaptive mechanisms in perceptual-motor coordination: components of prism adaptation.

Aftereffect measures of visual shift and proprioceptive shift were obtained for prism exposure conditions in which, at the end of a sagittal pointing movement, most of the arm was visible (concurrent exposure) or only the first finger joint was visible (terminal exposure). Intermediate exposure conditions permitted view of the hand or the first two finger joints. Under the concurrent exposure condition, proprioceptive shift was greater than visual shift but, as view of the pointing hand decreased, the relative magnitude of the two components gradually reversed so that, under the terminal exposure condition, visual shift was greater than proprioceptive shift. These results are discussed in terms of a model of perceptual-motor organization (Redding, Clark, & Wallace, 1985) in which the direction of coordinative linkage between eye-head and hand-head systems determines the locus of discordance and adaptive recalibration.

Journal Article↗
PubMed1988

Education against AIDS.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Heterogeneity of B-cell growth factor receptor reactivity in healthy donors and in patients with chronic lymphatic leukemia: relationship to B-cell-derived lymphokines.

Twenty-five long-term B-cell lines were studied for B-BCGF activity. The cell lines were cultured in the presence or absence of the new tumor promoter teleocidin, and control and teleocidin-treated derived supernatants were cocultured with purified B cells obtained from healthy donors and patients with B chronic lymphatic leukemia (B-CLL), in the presence of anti-mu. In attempt to delineate the role of other B-cell lymphokines in promoting proliferation of activated B cells, the supernatants were also studied for interleukin 1 (IL-1), interleukin 2 (IL-2), and interferon gamma (IFN-gamma). The effect of B-cell-derived lymphokines on the proliferation of activated B cells obtained from the 14 donors was heterogeneous, and three types of response were observed: In four healthy donors there was induction of B-cell proliferation by B-cell lymphokines derived from both control cells and teleocidin-treated cells. In cells obtained from the other five healthy donors there was induction of B-cell proliferation by B-cell lymphokines derived from teleocidin-treated cells. In the five B-CLL patients, B-cell proliferative response to B-cell lymphokines derived from both control cells and teleocidin-activated cells was absent. Comparison of B-BCGF reactivity to T-BCGF reactivity demonstrated that B-CLL B lymphocytes did not respond to either B-BCGF or T-BCGF, whereas normal B cells responded to T-BCGF and may proliferate upon stimulation with B-cell-derived IL-2 and/or B-BCGF. These results suggest heterogeneity of B-BCGF receptor reactivity in B lymphocytes derived from healthy donors, and lack of both B-BCGF and T-BCGF receptor reactivities in B lymphocytes derived from B-CLL patients; B-cell-derived lymphokines influence normal B-cell response but not leukemic B cells; B-BCGF optimal effect is in large part due to other B-cell lymphokines, especially B-cell-derived IL-2; the possible existence of various B-BCGFs.

Antigens, Surface↗
PubMed1986

Tyrosine 3-hydroxylase in rat brain and adrenal medulla: hybridization histochemistry and immunohistochemistry combined with retrograde tracing.

Rat brain and adrenal gland were analyzed by hybridization histochemistry using an RNA probe complementary to mRNA for tyrosine 3-hydroxylase (TyrOHase; tyrosine 3-monooxygenase, EC 1.14.16.2), by immunohistochemistry using TyrOHase antiserum, and by retrograde tracing using the fluorescent compound Fast blue. Cell bodies in the ventral mesencephalon contained mRNA for TyrOHase, and these cells were also TyrOHase immunoreactive. After injection of Fast blue into the striatum, such double-labeled cells in addition contained the retrograde tracer, showing that these cells send axonal projections to the injection site. These results show that hybridization histochemistry can be used to identify transmitter-specific neuron populations and that their projections can be established.

Adrenal Medulla↗
PubMed1986

Genetic changeover in Drosophila populations.

Three populations of Drosophila melanogaster that were daughter populations of two others with histories of high, continuous radiation exposure [population 5 (irradiated, small population size) gave rise to populations 17 (small) and 18 (large); population 6 (irradiated, large population size) gave rise to population 19 (large)] were maintained for 1 year with no radiation exposure. The frequency with which random combinations of second chromosomes taken from population 19 proved to be lethal changed abruptly after about 8 months, thus revealing the origin of a selectively favored element in that population. (This "element" may or may not have been the cause of the lethality.) A comparison of the loss of lethals in populations 17 and 18 with a loss that occurred concurrently in the still-irradiated population 5 suggests that a second, selectively favored element had arisen in that population just before populations 17 and 18 were split off. This element was on a nonlethal chromosome. The result in population 5 was the elimination of many lethals from that population, followed by a subsequent increase as mutations occurred in the favored nonlethal chromosome. Populations 17 and 18, with no radiation exposure, underwent a loss of lethals with no subsequent increase. The events described here, as well as others to be described elsewhere, suggest that populations may be subject to episodic periods of rapid gene frequency changes that occur under intense selection pressure. In the instances in which the changeover was revealed by the elimination of preexisting lethals, earlier lethal frequencies were reduced by approximately one-half; the selectively favored elements appear, then, to be favored in the heterozygous--not homozygous--condition.

Animals↗
PubMed1986

Latency and frequency reports to the Necker cube illusion: effects of hypnotic susceptibility and mental arithmetic.

An experiment (N = 32) was conducted to assess latency of first apparent reversal (AR) and AR frequency while observing the Necker cube illusion. Subjects who were either high in hypnotic susceptibility (susceptibles) or low in hypnotic susceptibility (resistant subjects) observed the cube either while performing or not performing mental addition problems. Susceptibles reported perceiving the first AR more quickly and a greater frequency of ARs than did resistant subjects. Also, latency of the first AR was negatively correlated with AR frequency. These results were interpreted in terms of the ability of susceptibles to allocate concentrative or selective attention in a manner that was conducive to faster performance, when faced with competing tasks.

Attention↗
PubMed1986

Eidetic-like imagery in hypnosis: rare but there.

The production of eidetic-like imagery during hypnosis in subjects with high but not low hypnotizability was supported in three separate experiments using nonfakable stereograms (Julesz, 1971; Gummerman, Gray, & Wilson, 1972). In Experiment 1, 6 (25%) of 24 stringently chosen, high hypnotizables were able to perceive one of the superimposed stereograms (presented monocularly) during conditions of standard hypnosis or hypnotic age regression, or under both conditions, but not during waking. In Experiments 2 and 3, low and high hypnotizables were presented stereograms in an alternating, monocular fashion (one-half to each eye). In Experiment 2, 10% of the high hypnotizables perceived one or more stereograms in hypnosis or age regression, but not during waking. In Experiment 3, none of the 17 low hypnotizables reported correct stereograms, but 6 of the 23 high hypnotizables (26%) did. Relationships between imagery performance and visuo-spatial abilities were investigated. Results support the general hypothesis that hypnosis enhances imaginal processing of information to be remembered that is a literal or untransformed representation.

Eidetic Imagery↗
PubMed1985

Hypnotic susceptibility, interference, and alternation frequency to the Necker cube illusion.

Two experiments (N = 60) were conducted to determine the effects of hypnotic susceptibility and interference on frequency of Necker cube apparent reversals (ARs). Interference was induced in Experiment 1 by having subjects respond to orally administered double-digit arithmetic (addition) problems while observing the Necker cube. In Experiment 2, counting backward by 3s served as interference. In both experiments, interference reduced ARs. Hypnotic susceptibility level also influenced ARs, with those scoring high on this attribute reporting more ARs than those scoring low. Attentional factors may have played a major role in producing the reported results.

Attention↗