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Biomedical subjects

D H Schroeder

Publications and source records attributed to D H Schroeder.

At least 19 recordsLinked to original sources
PubMed1996

The development of visual preferences in art-trained and non-art-trained schoolchildren.

Measures of four dimensions of visual preference (preferences for symmetry, simplicity, uniformity, and expressiveness) and a standardized test of visual-arts achievement were administered to art-trained and non-art-trained children in kindergarten, Grade 3, Grade 7, and high school. The art and non-art groups were matched at the school level on family income, English-language and ethnic backgrounds, school attendance, and school neighborhoods. The results showed effects for age and instruction, but the effects for instruction did not increase after Grade 3. The relative independence of the visual-preference dimensions from visual arts learning suggests they may measure individual differences that take shape early in development and are related to visual arts performance.

Achievement↗
PubMed1995

Carbamazepine but not valproate induces bupropion metabolism.

Bupropion (BUP) may be less likely than other antidepressants to cause switches into mania and rapid cycling, suggesting utility in bipolar disorder. The combination of BUP with the mood-stabilizing anticonvulsants carbamazepine (CBZ) or valproate (VPA) is a strategy that might further lessen the risk of mania. CBZ induces, and to a lesser extent VPA inhibits the hepatic metabolism of various medications, but their effects on BUP have not been previously studied. Inpatients with mood disorders had pharmacokinetic profiles of BUP and metabolites assessed after single, oral, 150-mg doses of BUP while receiving placebo (N = 17) or during chronic blind CBZ (N = 12) or VPA (N = 5) monotherapy. CBZ but not VPA therapy decreased BUP peak concentrations (Cmax) by 87% (p < 0.0001) and 24-h area under the curve (AUC) by 90% (p < 0.0001), threohydrobupropion Cmax by 81% (p <0.0009) and AUC by 86% (p < 0.002), and erythropydrobupropion Cmax by 86% (p < 0.05) and AUC by 96% (p < 0.05). CBZ increased hydroxybupropion (H-BUP) Cmax by 71% (p < 0.007) and AUC by 50% (p < 0.09) and H-BUP AUC by 94% (p < 0.02). Thus, CBZ markedly decreased BUP and increased H-BUP concentrations, whereas VPA did not affect BUP but increased H-BUP concentrations. Further studies are required to determine how these differential effects of CBZ and VPA on BUP pharmacokinetics influence the tolerability and efficacy of combination therapies with these agents.

Adult↗
PubMed1993

Gender, laterality, learning difficulties and health problems.

This paper examines the association between self-reported laterality, learning difficulties and health problems. Responses to questionnaire data were obtained from 3829 males and 3631 females. Males reported increased cardiovascular disease, ulcers, and diabetes. Learning problems were increased in males, nonright-handers and those with a left eye preference. The highest proportion of difficulty learning to read was in males who were nonright-handed and right-eyed. Mixed dominance, however, did not fully explain the results since nonright-handers with left eye preferences had the next highest rate.

Adolescent↗
PubMed1993

Excretion of bupropion in breast milk.

OBJECTIVE: To measure the excretion of bupropion and its metabolites in breast milk. A secondary objective was to determine whether the drug accumulated in the nursing infant. CASE SUMMARY: Milk and plasma samples were collected from a woman taking bupropion 300 mg/d in divided doses who was breastfeeding her 14-month-old son. A single plasma sample was collected from the infant. RESULTS: After a 100-mg dose, the peak bupropion breast milk concentration measured at two hours was 0.189 micrograms/mL. Milk-to-plasma ratios ranged from 2.51 to 8.58 over a six-hour interval. Two of three metabolites also were measured in milk. Bupropion and its metabolites were not detected in the single plasma sample obtained from the infant. CONCLUSIONS: Bupropion accumulates in human breast milk in concentrations much higher than in maternal plasma. Two metabolites are also excreted into the milk. Neither bupropion nor its metabolites were detected in the infant's plasma, indicating that accumulation did not occur in this infant.

Adult↗
PubMed1989

Toward a departmental bottom-line perspective.

In the absence of developing a relationship between price paid and cost expended, health care management has no basis for setting financial objectives much less subsequent evaluation. Departmental P&Ls bring the cost-price relationship into perspective.

Accounting↗
PubMed1987

Pharmacological significance of the species differences in bupropion metabolism.

Bupropion provided a dose-dependent prevention of tetrabenazine-induced sedation in mice but not rats. Bupropion was extensively metabolized in mice, rats, dogs and man. About 85% of the dose was excreted in urine of rats and man. The predominant metabolites in rat urine were side chain cleavage products of bupropion (m-chlorobenzoic acid) with a minor fraction consisting of basic side chain hydroxylated metabolites. Mice, dogs and man form a major side chain hydroxylated product (BW 306U) which appeared in higher concentration than bupropion in plasma of these species but not rats. The relatively high plasma levels of BW 306U in mice but not rats may account for the species difference in pharmacological response observed with bupropion.

Animals↗
PubMed1984

Influence of life event stress on physical illness: substantive effects or methodological flaws?

This study tests the hypothesis that the reported relationship between life event stress and physical illness is primarily a function of criterion and other content contamination in the stress measure. In particular, conventional life event measures include events related to physical health, which overlap with the criterion; events related to neuroticism, which influences the criterion; and events that are vague or subjective and could be affected by individual differences in psychological distress, response sets, and retrospective bias. In this study 386 adult males and females completed standard measures of life events and physical illness. Illness was significantly related to event subscales containing, respectively, health-related events, neuroticism-related events, and subjective events, but not to an "uncontaminated" event subscale. These results support the hypothesis of contamination and suggest that alternative approaches to the conceptualization and measurement of stress may need to be developed.

Adult↗
PubMed1983

Radioimmunoassay for bupropion in human plasma: comparison of tritiated and iodinated radioligands.

We evaluated the potential usefulness of 125I-labeled p-hydroxybupropion in a direct radioimmunoassay for bupropion in human plasma as compared with a currently used [3H]bupropion dextran-coated charcoal method. In both radioimmunoassay methods succinoylpropylbupropion antiserum was used that was highly specific for unchanged drug, cross reactivities with known bupropion metabolites being less than 0.3%. However, the use of 125I-labeled p-hydroxybupropion afforded greater sensitivity (0.3 microgram/L vs 0.6 microgram/L with [3H]bupropion) and was readily adaptable to the more convenient polyethylene glycol separation method. Between-assay CVs were 3.8 to 12.2% (mean 7.6%) with the 125I-based radioimmunoassay and 5.1 to 11.5% (mean 7.5%) with the 3H-based assay. Agreement between the two radioimmunoassay determinations of buproprion in human plasma samples collected over a 60-h period after oral drug administration was excellent (slope = 1.086, r = 0.989). We find the 125I-based assay a convenient and suitable alternative to the [3H]bupropion assay in pharmacokinetic studies in humans.

Adult↗
PubMed1983

Metabolism and kinetics of bupropion.

Studies of bupropion in rats, dogs, and normal volunteers showed that bupropion was rapidly and completely absorbed, widely distributed in tissues, and metabolized extensively prior to its excretion. Metabolism in rats and dogs appeared to be predominantly by side chain oxidative cleavage, while reduction of the intact parent aminoketone to an aminoalcohol was an additional major pathway in man. Most of the metabolites were excreted in urine. Bupropion, but not its metabolites, was concentrated in many tissues, with a brain to plasma ratio of about 25:1. Plasma protein binding of bupropion (75%-80%) did not seem to limit its tissue distribution. Bupropion was found to be a weak to moderate inducer of drug metabolism.

Animals↗
PubMed1983

Clinical pharmacokinetics of bupropion: a review.

Bupropion is absorbed rapidly after single-dose oral administration of tablets, capsules, or aqueous solution of the hydrochloride salt. Peak bupropion plasma concentrations are generally attained within 2 hours, followed by a biphasic decline. The half-life of the initial (alpha) phase is approximately 1.5 hours and that of the second (beta) phase is approximately 14.0 hours. An oral dose of bupropion is subjected to extensive first-pass metabolism. The ratio between plasma clearance and fraction absorbed (approximately 2 L/hr/kg) is consistent within the 50-250 mg single dose range.

Administration, Oral↗
PubMed1981

Reputation, training, fee, and androgyny: their comparative effects on impressions of therapist credibility.

Two hundred and forty-eight college students viewed a vignette from a therapy-analogue session. Before Ss viewed the vignette they all read a summary that described the vignette plus an additional description that stressed different aspects of the therapist. One-fifth of the Ss were told of the therapist's excellent reputation, one-fifth were told of the therapist's excellent training and credentials, one-fifth were told of the therapist's high fee, and one-fifth were told of the therapists' androgenous personality. The remaining one-fifth of the Ss, who served as controls, were told nothing further; they only received the standard description of the vignette. After the vignette, Ss completed measures designed to assess their perception of therapist credibility and attractiveness. The results indicate that the androgenous therapist was rated as most credible and attractive (whereas the high-fee-charging therapist was least credible and attractive.) Explanation for these results and implications are discussed.

Attitude↗
PubMed1981

Pharmacokinetics of bupropion, a novel antidepressant agent, following oral administration to healthy subjects.

The pharmacokinetics of bupropion hydrochloride, a structurally novel antidepressant agent, have been studied in healthy male and female subjects following administration of single oral doses of 50, 100 and 200 mg. Plasma drug concentrations were determined directly by a specific radioimmunoassay (r.i.a.), while urinary measurements required a prior solvent extraction to remove substances interfering in the assay. Bupropion appeared rapidly in the plasma, suggesting good absorption. Drug plasma concentration-time data were fitted well to a two-compartment open model of drug disposition by use of the computer program NONLIN. By comparison of AUC, Cmax and tmax values, the pharmacokinetics of bupropion were found to be linear across the 50-200 mg dose range in both sexes. When the data were normalized for subjects' body weights, no differences between pharmacokinetic parameters for male and female subjects were found. Mean disposition half-lives across treatments were 1.2-1.4 h for t1/2 alpha and 10.7-13.8 h for the t1/2 beta. Bupropion was extensively bound (85%) to human plasma proteins over a wide drug concentration range. Less than 1% of a 200 mg oral dose of bupropion hydrochloride appeared in the urine of 16 subjects as unchanged drug, indicating extensive metabolism of the parent compound.

Administration, Oral↗
PubMed1981

Radioimmunoassay and pharmacokinetic profile of bupropion in the dog.

A radioimmunoassay (RIA) procedure for the quantification of bupropion (dl-2-tert-butylamino-3'-chloropropiophenone) in biological fluids is described. Immunization of rabbits with conjugates of bovine serum albumin and p-succinoyl propylbupropion or p-carbomethoxybupropion resulted in the production of antisera which are capable of detecting less than 1 ng ml-1 (100 pg actual mass) of bupropion in the RIA, utilizing [6-3H] bupropion as radioligand. The antisera used in these studies have low cross-reaction (approximately 0.1% or less) with known side chain metabolites of bupropion, but exhibit significant cross-reaction with p-hydroxybupropion (30.3%). Excellent agreement was obtained between RIA and high-pressure liquid chromatography determinations of bupropion concentrations in human plasma samples, but plasma or serum from bupropion-treated dogs, rats and mice required extraction from basic medium to remove some interference before RIA. The assay was applied to a study of bupropion disposition in two beagles of each sex after i.v. and p.o. administrations of bupropion hydrochloride (100 mg). The pharmacokinetic profile in dogs was best described by an open two-compartment model after either route of drug administration. Peak plasma bupropion levels after oral dosing were highly variable, ranging from 12.9 to 63.5 ng ml-1 at 26 to 32 min after drug administration. The mean terminal phase half-life of bupropion was calculated to be 1.73 hr after either route and the absolute oral bioavailability of the drug varied from 2.0 to 6.5%.

Animals↗
PubMed1979

Attraction to therapy and therapist credibility as a function of therapy orientation.

Exposed male and female Ss (N = 96) to psychoanalytic, behavioral, client-centered, or gestalt therapy, in the form of a brief written description and a 5-minute videotaped simulation. Attraction to therapy and various dimensions of therapist credibility were measured. The psychoanalytic presentation generated the greatest attraction and the greatest perceived total credibility. The gestalt presentation was next highest on these variables, followed by the behavioral and client-centered presentation. No significant effects for sex of S or sex by therapy approach interaction were reported. Explanations for and implications of these findings are discussed.

Attitude↗