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51.
Stephanie Moriceau Tania L. Roth Terri Okotoghaide Regina M. Sullivan 《International journal of developmental neuroscience》2004,22(5-6):415-422
In many altricial species, fear responses such as freezing do not emerge until sometime later in development. In infant rats, fear to natural predator odors emerges around postnatal day (PN) 10 when infant rats begin walking. The behavioral emergence of fear is correlated with two physiological events: functional emergence of the amygdala and increasing corticosterone (CORT) levels. Here, we hypothesize that increasing corticosterone levels influence amygdala activity to permit the emergence of fear expression. We assessed the relationship between fear expression (immobility similar to freezing), amygdala function (c-fos) and the level of corticosterone in pups in response to presentation of novel male odor (predator), littermate odor and no odor. CORT levels were increased in PN8 pups (no fear, normally low CORT) by exogenous CORT (3 mg/kg) and decreased in PN12 pups (express fear, CORT levels higher) through adrenalectomy and CORT replacement. Results showed that PN8 expression of fear to a predator odor and basolateral/lateral amygdala activity could be prematurely evoked with exogenous CORT, while adrenalectomy in PN12 pups prevented both fear expression and amygdala activation. These results suggest that low neonatal CORT level serves to protect pups from responding to fear inducing stimuli and attenuate amygdala activation. This suggests that alteration of the neonatal CORT system by environmental insults such as alcohol, stress and illegal drugs, may also alter the neonatal fear system and its underlying neural control. 相似文献
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53.
Helen Tager-Flusberg Kate Sullivan 《Journal of autism and developmental disorders》1994,24(5):577-586
Compared the performance of autistic and mentally retarded subjects, all of whom had passed a standard first-order test of false belief, on a new second-order belief task 12 autistic and 12 mentally retarded subjects, matched on verbal mental age (assessed by PPVT and a sentence comprehension subtest of the CELF) and full-scale IQ were given two trials of a second-order reasoning task which was significantly shorter and less complex than the standard task used in all previous research. The majority of subjects in both groups passed the new task, and were able to give appropriate justifications to their responses. No group differences were found in performance on the control or test questions. Findings are interpreted as evidence for the role of information processing factors rather than conceptual factors in performance on higher order theory of mind tasks.This study was supported by a grant from the National Institute of Deafness and Other Communication Disorders (1RO1 DC 01234). We thank Jason Barker for his extensive help with this study. We are also very grateful to the schools where the study was conducted including the League School, and the public school systems in the following towns in Massachusetts: Hanover, Hanson, Hingham, Milton, Plymouth, and Rockland. We offer special thanks to Alan Dewey, Mary Dollar, Sandy D'Giacomo, Herman Fishbein, William Griffin, Nancy Kearns, Judy Monahan, Debbie Newhall, Cay Riley, Robert Sherman, and Kathy Staska for their continued support of our research. 相似文献
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55.
Patrick Sullivan 《Canadian Medical Association journal》1995,152(2):253-255
Potential changes to registered retirement savings plan (RRSP) regulations “continue to generate a huge amount of concern” among physicians, the Board of Directors was told at its December meeting. That anxiety explains why the RRSP issue and related lobbying will remain at the top of the CMA's priority list in 1995. The other major topic of concern during the 3-day meeting was the federal government's proposed gun-control legislation. If doctors are going to have a responsibility to report patients whose ownership of firearms may make them a danger to themselves or others, the CMA wants to ensure that physicians who make such reports are protected under the law. 相似文献
56.
Xiaohua He Edith V Sullivan Roger K Stankovic Clive G Harper Adolf Pfefferbaum 《Neuropsychopharmacology》2007,32(10):2207-2216
The relative roles of alcohol and thiamine deficiency in causing brain damage remain controversial in alcoholics without the Wernicke-Korsakoff syndrome. Experimental control over alcohol consumption and diet are impossible in humans but can be accomplished in animal models. This experiment was designed to differentiate the separate and combined effects on the macro- and ultrastructure of the corpus callosum of thiamine deficiency and voluntary alcohol consumption. Adult male alcohol-preferring (P) rats (9 chronically alcohol-exposed and 9 water controls) received a thiamine-deficient diet for 2 weeks. There were four groups: five rats previously exposed to alcohol were treated with pyrithiamine (a thiamine phosphorylation inhibitor); five rats never exposed to alcohol were treated with pyrithiamine; four alcohol-exposed rats were treated with thiamine; and four rats never exposed to alcohol were treated with thiamine. On day 14, thiamine was restored in all 18 rats; 2 weeks later the 10 pyrithiamine-treated rats received intraperitoneal thiamine. The rats were perfused 61 days post-pyrithiamine treatment at age 598 days. Brains were dissected and weight and volumes were calculated. Sagittal sections were stained to measure white matter structures. The corpus callosum was examined using transmission electron microscopy to determine density of myelinated fibers, fiber diameter, and myelin thickness. The corpus callosum in the alcohol/pyrithiamine group was significantly thinner, had greater fiber density, higher percentage of small fibers, and myelin thinning than in the alcohol/thiamine and water/thiamine groups. Several measures showed a graded effect, where the alcohol/pyrithiamine group had greater pathology than the water/pyrithiamine group, which had greater pathology than the two thiamine-replete groups. Across all 16 rats, thinner myelin sheaths correlated with higher percentage of small fibers. Myelin thickness and axon diameter together accounted for 71% of the variance associated with percentage of small fibers. Significant abnormalities in the alcohol/pyrithiamine group and lack of abnormality in the alcohol-exposed/thiamine-replete group indicate that thiamine deficiency caused white matter damage. The graded abnormalities across the dually to singly treated animals support a compounding effect of alcohol exposure and thiamine depletion, and indicate the potential for interaction between alcohol and thiamine deficiency in human alcohol-related brain damage. 相似文献
57.
58.
M Mathru B Kleinman B Blakeman H Sullivan P Kumar D J Dries 《Critical care medicine》1992,20(10):1420-1425
OBJECTIVE: This study was designed to evaluate the oxygen transport adjustments and myocardial metabolic adaptation that occurs with different levels of hemodilution during normothermia after cardiopulmonary bypass. DESIGN: Prospective, nonrandomized study. SETTING: Operating room in a university hospital. PATIENTS: Eight patients with ejection fractions (> 40%) undergoing elective coronary artery bypass grafting. METHODS: Before the institution of cardiopulmonary bypass, blood was withdrawn from patients to a target hematocrit of 15%. After coronary artery bypass grafting, a catheter was inserted directly into the coronary sinus. After the patients were rewarmed to 37 degrees C, they were weaned from cardiopulmonary bypass. Hemodynamic indices were measured, as well as measurements of myocardial oxygen consumption (VO2) and myocardial metabolism (lactate extraction and coronary sinus hypoxanthine). Measurements were made at three different hematocrit values: 15%, 20%, and 25%. Hematocrit was increased by autologous blood transfusion. MEASUREMENTS AND MAIN RESULTS: The three levels of hemodilution (hematocrit: 17.4 +/- 3.4%; 23.0 +/- 3.7%; 27.8 +/- 4.8%) were significantly different from baseline (hematocrit 37 +/- 2.6%; p < .05). Oxygen delivery, which increased with autologous transfusion, exceeded 350 mL/min/m2 at each level of dilution. The myocardial VO2 increased significantly after autologous transfusion compared with the most dilute condition (7.0 +/- 3.7 mL/min at hematocrit 17.4% vs. 11.2 +/- 4.8 mL/min at hematocrit 23.0% and 12.4 +/- 4.0 mL/min at hematocrit 27.8%). This transfusion-induced increase was also true of myocardial oxygen extraction. Lactate extraction and hypoxanthine release were normal and unchanged at each level of hemodilution. Systemic oxygen extraction ratio increased with hemodilution and decreased with autologous transfusion. CONCLUSIONS: Hemodilution to a hematocrit of approximately 15% is tolerated in anesthetized humans after coronary artery bypass surgery. There was no evidence of myocardial ischemia, as demonstrated by absence of S-T depression on the electrocardiogram, lactate extraction, or hypoxanthine release. In selected patients, postoperative transfusion may be based on systemic physiologic end-points, such as oxygen extraction ratio, rather than set hematocrit values. 相似文献
59.
60.
K L Preston J T Sullivan E C Strain G E Bigelow 《The Journal of pharmacology and experimental therapeutics》1992,262(1):279-291
This study was conducted to determine whether the acute administration of bromocriptine, a dopamine agonist, modulates the acute pharmacologic effects of i.v. cocaine in humans. Eight current users of i.v. cocaine who were not seeking treatment for their cocaine abuse completed the study while they were inpatients on a research unit. Twelve drug conditions were tested in all subjects in randomized order under double-blind, double-dummy conditions and included cocaine (0, 12.5, 25 and 50 mg, i.v.) in combination with bromocriptine (0, 1.2 and 2.5 mg given orally 2 hr before the cocaine injection). Physiologic and subject- and observer-rated responses were measured. Cocaine alone significantly increased pupil diameter, heart rate and blood pressure, and ratings of drug effect, good effects, liking and rush. Bromocriptine alone significantly increased pupil diameter and heart rate, decreased blood pressure and had only minor effects on subjective measures. There were significant cocaine/bromocriptine interactions on diastolic and mean arterial blood pressure, with combinations producing significantly smaller increases compared to cocaine alone, and on heart rate, with combinations producing significantly larger increases compared to cocaine alone. The physiologic and subjective effects of cocaine were not modified by pretreatment with bromocriptine in any other way that might indicate either a therapeutic benefit or a safety concern. However, bromocriptine alone produced undesirable effects (fainting) that should be considered before administration to outpatient cocaine abusers. Any possible therapeutic benefits of acute administration of bromocriptine in cocaine abuse are not likely to be due directly to modulation of the acute effects of cocaine. 相似文献