Search PubMed⌕ Search

Biomedical subjects

J M Bailey

Publications and source records attributed to J M Bailey.

At least 73 records · Page 4Linked to original sources
PubMed1995

Systemic activation of 15-lipoxygenase in heart, lung, and vascular tissues by hypercholesterolemia: relationship to lipoprotein oxidation and atherogenesis.

There is evidence that oxidized lipoproteins are a major contributing factor in atherosclerosis. 15-Lipoxygenase is the principal mammalian enzyme that can oxidize polysaturated fatty acids present in intact lipoproteins, and in membrane phospholipids in situ. We, and others, have reported previously that levels of the enzyme are increased in aortas of cholesterol-fed and spontaneously atherosclerotic WHHL rabbits. In the present study, rabbits were fed an atherogenic diet containing 1% cholesterol for 14 weeks, and levels of [14C]arachidonate metabolizing enzymes in the excised tissues were measured by HPLC analysis. 15-Lipoxygenase levels in heart, aortic adventitia, and lung, but not in liver, were increased up to 100-fold above controls, without major significant changes in prostaglandin endoperoxide synthases or the 5- and 12-lipoxygenases. The induced 15-lipoxygenase activity in the aortic adventitia was approximately 15 times greater than that found in the vessel wall. Hypercholesterolemia and elevated 15-lipoxygenase were associated with a 40% lowering of blood hematocrit. The hemolytic agent phenylhydrazine duplicated the effects of hypercholesterolemia on hematocrit, and induced up to 100-fold increases in 15-lipoxygenase activity in tissues within 7 days. The induced 15-lipoxygenase activities in heart and lung were 4 and 8 times greater, respectively, than in reticulocytes, previously the richest known source of the enzyme. Direct measurements of hemoglobin content also demonstrated that contaminating reticulocytes were not the source of the tissue enzyme. A similar tissue-specific activation of 15-lipoxygenase was observed in rat heart and lung, but also not in liver. It is concluded that the elevated level of 15-lipoxygenase activity previously reported in atherosclerotic aorta is symptomatic of a generalized and massive induction of the enzyme in cardio-pulmonary tissues by hypercholesterolemia, which may be related to the membrane perturbation and increased hemolysis that is induced by cholesterol feeding.

Animals↗
PubMed1995

Aggressiveness, competitiveness, and human sexual orientation.

Previous research has suggested that homosexual men are less aggressive than heterosexual men, but limitations of available studies prevent them from being conclusive. The empirical evidence is even more mixed regarding the relation of aggressiveness to female sexual orientation. We examined the relation between self-reported physical and verbal aggressiveness, interpersonal competitiveness, and sexual orientation in both men and women. The aggressiveness and competitiveness scales yielded significant sex differences, with men being more aggressive and competitive. Consistent with past findings, heterosexual men were more physically aggressive than were homosexual men; no other within-sex relationship was significant. We discuss the implications of our findings for developmental theories of sexual orientation, aggressiveness, and competitiveness.

Adult↗
PubMed1995

Spatial ability, handedness, and human sexual orientation.

We investigated the relations among mental rotations and spatial perception abilities, handedness, and sexual orientation in both men and women. The present study included a relatively large sample and attempted to control statistically for important covariates such as general intelligence. Significant sex differences were obtained for mental rotations and spatial perception, but not for handedness. None of these measures was significantly related to sexual orientation within either sex.

Adult↗
PubMed1995

A comparison of transesophageal and transthoracic echocardiographic assessment of left ventricular function in pediatric patients with congenital heart disease.

OBJECTIVE: To determine the quantitative utility of transesophageal echocardiographic assessments of left ventricular function in pediatric patients with congenital heart disease by evaluating the variability between observers and between echocardiographic windows. DESIGN: Retrospective, blinded analysis. SETTING: University-associated pediatric hospital. PARTICIPANTS: Transthoracic and transesophageal echocardiographic images of 25 pediatric patients with congenital heart disease were reviewed. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: End-diastolic area, end-systolic area, and fractional area change were measured from short-axis images of the left ventricle at the midpapillary level by two separate investigators. These measurements were compared by the method of Bland and Altman and Sheiner and Beal. Significant differences in measurements of end-diastolic and end-systolic area by different observers were noted, but they were systematic. A similar situation was noted for the comparison of transthoracic and transesophageal measurements of end-diastolic and end-systolic area. In the comparison of fractional area change between observers or windows, bias and absolute prediction error were lower, with 95% confidence limits of bias or absolute prediction error of 10% or less. CONCLUSIONS: The potential error in the measurement of fractional area change in 10% under optimal conditions. This would suggest that the assessment of ventricular function in the operating room or intensive care unit, under less than optimal conditions, should be viewed as a qualitative, rather quantitative, measurement. There may be significant interobserver and interwindow variability.

Bias↗
PubMed1995

The effects of milrinone on platelets in patients undergoing cardiac surgery.

Although amrinone produces thrombocytopenia, no information is available regarding the acute effects of milrinone on platelets. Therefore, we evaluated the effects of milrinone on platelet number and function in cardiac surgical patients. Twenty-seven patients were studied during cardiac surgery requiring cardiopulmonary bypass (CPB). Patients were randomized to receive no milrinone (n = 10), or milrinone (n = 17) at a loading dose of 50-75 micrograms/kg in the CPB circuit followed by 0.5-0.75 micrograms.kg-1.min-1 for 12-24 h. Bleeding times and blood samples for coagulation studies were obtained prior to induction, and at 2 and 24 h after CPB. In both groups, platelet counts decreased significantly from the baseline at 2 and 24 h after CPB, and bleeding time increased significantly from the baseline at 2 and 24 h after CPB. No significant thromboelastoplasty (TEG) changes were observed in either group, and there were no significant differences in platelet aggregation or chest tube drainage between the groups. Acute milrinone administration did not cause significant changes in platelet number or function in patients undergoing cardiac operations requiring CPB, beyond the usual adverse effects of cardiac surgery and CPB.

Adult↗
PubMed1995

Technique for quantifying the duration of intravenous anesthetic effect.

BACKGROUND: Several recent studies have analyzed the relationship between pharmacokinetic parameters and the rate of decrease in concentration after discontinuation of a continuous drug infusion. Although these studies have clarified our understanding of those aspects of pharmacokinetics most relevant to anesthesia practice, they do not directly address the issue of the duration of drug effect, which will be a function of both pharmacokinetic and pharmacodynamic variables. This paper extends these concepts by presenting a method to unify pharmacokinetics and pharmacodynamics in a measure of duration of drug effect that is applicable when the drug effect is assessed in a binary, response/no response fashion. METHODS: The parameter proposed to quantify duration of drug effect is the area under the curve expressing probability of drug effect as a function of time after the agent is discontinued. This parameter is denoted the mean effect time. It is calculated using the logistic (or Hill) equation to relate the probability of drug effect to drug concentration, which in turn can be calculated as a function of time by pharmacokinetic simulation. Mean effect times were calculated for sufentanil, alfentanil, propofol, and midazolam using the logistic equation describing recovery and by assuming that drug blood concentrations during maintenance of anesthesia were sufficient to reduce the probability of responsiveness to surgical stimulation to 10% (C90). Published pharmacokinetic and pharmacodynamic parameters were used for these calculations. These results were compared to the relevant decrement times (as defined in this paper, the time required for the concentration to decrease from C90 to the concentration at which 50% of patients are responsive and/or able to maintain adequate ventilation, denoted C50). It was assumed that C90 and C50 were independent variables. RESULTS: Mean effect times for midazolam and propofol, for which the steepness parameter delta for recovery (responsiveness and adequate ventilation) is less than 4, are significantly greater than the decrement time. Mean effect times for sufentanil and alfentanil (delta = 6 and 10, respectively) are close to decrement times. The discrepancy between mean effect time and decrement time becomes greater as the duration of drug administration increases. The incorporation of pharmacokinetic variability into the calculations had little effect on the results. CONCLUSIONS: Context-sensitive half-times or other decrement times have been shown to be the most useful measures of the kinetics of drug concentrations. Mean effect time may be a useful concept for understanding the recovery from drug effects.

Anesthesia Recovery Period↗
PubMed1995

A biologic perspective on sexual orientation.

Sexual orientation may be defined as the sustained erotic attraction to members of one's own gender, the opposite gender, or both--homosexual, heterosexual, or bisexual, respectively. Interest in sexual orientation is as old as the science of psychology, yet many fundamental issues remain unresolved. This article reviews research in the development and psychopathology of sexual orientation as well as the results of family and twin studies. Research in genetic linkage, sex hormones, and brain differences also is discussed.

Adolescent↗
PubMed1994

A two-domain structure for the two subunits of NAD(P)H:quinone acceptor oxidoreductase.

NAD(P)H:quinone acceptor oxidoreductase (EC 1.6.99.2) (DT-diaphorase) is a FAD-containing reductase that catalyzes a unique 2-electron reduction of quinones. It consists of 2 identical subunits. In this study, it was found that the carboxyl-terminal portion of the 2 subunits can be cleaved by various proteases, whereas the amino-terminal portion cannot. It was also found that proteolytic digestion of the enzyme can be blocked by the prosthetic group FAD, substrates NAD(P)H and menadione, and inhibitors dicoumarol and phenindione. Interestingly, chrysin and Cibacron blue, 2 additional inhibitors, cannot protect the enzyme from proteolytic digestion. The results obtained from this study indicate that the subunit of the quinone reductase has a 2-domain structure, i.e., an amino-terminal compact domain and a carboxyl-terminal flexible domain. A structural model of the quinone reductase is generated based on results obtained from amino-terminal and carboxyl-terminal protein sequence analyses and electrospray mass spectral analyses of hydrolytic products of the enzyme generated by trypsin, chymotrypsin, and Staphylococcus aureus protease. Furthermore, based on the data, it is suggested that the binding of substrates involves an interaction between 2 structural domains.

Amino Acid Sequence↗
PubMed1994

A technique for calculating the mean time for equilibration of drug distribution using minimal structural assumptions.

Disposition decomposition analysis is used as a framework to derive a parameter for the description of drug distribution kinetics. This parameter, denoted td, is a measure of the mean time for equilibration of distribution in the absence of metabolic drug elimination. The derivation requires only the assumption that distribution is linear, and is generally valid as long as any nonlinearity is due to central nonlinear elimination. The mean time for equilibration of distribution, td, is evaluated in terms of the moments of the distribution function, h(t), derived by disposition decomposition analysis. Estimates of td for several drugs are presented.

Models, Chemical↗
PubMed1994

Effects of gender and sexual orientation on evolutionarily relevant aspects of human mating psychology.

Sexual selection theory provides a powerful model for the analysis of psychological sex differences. This research examined (a) tests of several sex differences in mating psychology predicted from sexual selection theory, (b) broad developmental hypotheses about sex differences in mating psychology--through the relationship of mating psychology to sexual orientation, and (c) the structure of within-sex differences in mating psychology. Scales measuring aspects of mating psychology were administered to heterosexual and homosexual Ss of both sexes. The structure of scale intercorrelations was similar across groups. All scales yielded sex differences consistent with sexual selection theory. Homosexual Ss generally obtained scores similar to those of same-sex heterosexual Ss, though several scales were significantly related to sexual orientation. Findings constrain hypotheses concerning the origins of sex differences.

Adult↗