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Biomedical subjects

D J Schroeder

Publications and source records attributed to D J Schroeder.

At least 19 recordsLinked to original sources
PubMed1996

Organochlorine contaminants in double-crested cormorants from Green Bay, WI: I. Large-scale extraction and isolation from eggs using semi-permeable membrane dialysis.

A 41.3-kg sample of double-crested cormorant (Phalacrocorax auritus) egg contents was extracted, yielding over 2 L of egg lipid. The double-crested cormorant (DCC) egg extract, after clean-up and concentration, was intended for use in egg injection studies to determine the embryotoxicity of the organic contaminants found within the eggs. Large-scale dialysis was used as a preliminary treatment to separate the extracted contaminants from the co-extracted sample lipids. The lipid was dialyzed in 80x5 cm semi-permeable membrane devices (SPMDs) in 50-ml aliquants. After the removal of 87 g of cholesterol by freeze-fractionation, the remaining lipid carryover (56 g) was removed by 100 routine gel permeation chromatography (GPC) operations. A 41,293-g sample was thus extracted and purified to the extent that it could easily be placed at a volume of 5 ml, the volume calculated to be necessary for the egg injection study. Analyses were performed comparing contaminant concentrations in the final purified extract to those present in the original egg material, in the extract after dialysis and cholesterol removal, and in the excluded materials. Recoveries of organochlorine pesticides through dialysis and cholesterol ranged from 96% to 135%. Total polychlorinated biphenyls in the final extract were 96% of those measured in the original egg material. Analysis of excluded lipid and cholesterol indicated that 92% of the polychlorinated dibenzo-dioxins and -furans were separated into the final extract.

Animals↗
PubMed1995

Nicotine therapy in patients with Alzheimer's disease.

Further studies are needed to determine the long-term effects nicotine may have in patients with Alzheimer's disease. In addition, one must consider the risks of using a chemical that is considered a health hazard to treat a patient with Alzheimer's disease. It would be beneficial to develop a compound similar to but less toxic than nicotine to study and possibly treat patients with Alzheimer's disease. Until alternatives are developed, a trial of nicotine administered transdermally may provide hope and a greater understanding of Alzheimer's disease.

Administration, Cutaneous↗
PubMed1995

Psyllium in hypercholesterolemia.

In summary, within a controlled study situation, psyllium seems to be effective in lowering total and LDL cholesterol by 4-8% and 6-13%, respectively. Compared with conventional antilipidemic agents such as lovastatin, which lowers total cholesterol 30%, LDL cholesterol 40%, and triglycerides 20%, the effect of psyllium on lipids is minimal, and its use as a form of drug therapy in patients with moderate-to-severe hypercholesterolemia is not recommended. As an adjunct to AHA step 1 diet therapy, however, psyllium can be useful. The NCEP recently has stressed diet therapy as a first-line primary intervention in patients not a high risk from multiple risk factors or very high LDL cholesterol concentrations. Men ( < or = 45 y) and premenopausal women with no other risk factors and moderately high LDL cholesterol concentrations (4.1-5.7 mmol/l) are at relatively low risk for coronary events in the near future, and would therefore be suitable for diet therapy combined with adjunctive psyllium therapy. Psyllium is well tolerated with minor transient adverse effects (abdominal distention, excessive gas, flatulence) and has a good compliance record ( > or = 90%). It would be a useful adjunct to dietary intervention in low-risk patients with mild-to-moderate hypercholesterolemia. Further research is needed to evaluate psyllium's effect in women and its efficacy in long-term use.

Cholesterol, LDL↗
PubMed1991

Relationships of anxiety scores to screening and training status of air traffic controllers.

The present study assessed the relationship between anxiety, as measured by the State-Trait Personality Inventory (STPI), and success of post-strike air traffic control specialist (ATCS) trainees at the FAA Academy and during field training. The STPI was administered to students who entered the FAA Academy between June 1984 and September 1985. Academy test scores were obtained for 1,790 students in the en route option. Criterion data included the field training status of the Academy graduates as of July 1988. Statistical analyses determined the relationships between ATCS student scores on the STPI measures and a) normative data and b) Academy screening and field training results. ATCS students reported significantly lower state (current level) and trait (proneness) levels of anxiety than did either college students or military recruits. Trainees who had relatively high scores (for ATCSs) on a combined index of the trait and state measures of anxiety exhibited significantly higher a) percentages of Academy failures/withdrawals, b) percentages of option switches in the field, and c) overall field attrition, than did trainees with low scores. Results support the operation of some personality-related self-selection among ATCS applicants regarding anxiety and the importance of this low anxiety characteristic for ATCS job success.

Aerospace Medicine↗
PubMed1985

Self-awareness and self-confrontation: effects of self-focused attention on members of a clinical population.

Research in the area of self-awareness theory has indicated that self-focused attention consistently produces both an increase in perceived intensity of affect and enhanced accuracy of self-reports. The present studies consider these effects in relation to the technique of self-confrontation as used in psychotherapy. In the first study, members of two different clinical populations (alcoholics and general psychiatric patients) either were or were not made self-aware and then were asked to self-report on their psychiatric problems and their mood states. Results indicated that self-awareness did increase the negative mood states for the psychiatric patients, and it also apparently increased the accuracy with which both patient groups reported on their history of hospitalization. In the second study self-awareness once again exacerbated the reported negative affect of a group of depressed psychiatric patients and enhanced the accuracy with which they reported on their hospitalizations. Additional analyses indicated that although the psychiatric patients generally felt worse when self-aware, they were also more accurate in their self-reports, including descriptions of their problems. The effects of self-awareness on members of clinical population are discussed and related to self-confrontation techniques.

Adult↗
PubMed1985

The effect of a purified water-soluble fraction of a Fusarium roseum 'Graminearum' culture on reproduction of white Leghorn females.

White Leghorn females (36 weeks old) in egg production were individually fed a purified water-soluble fraction residue remaining from the water extract and a crude culture of Fusarium roseum 'Graminearium'. Each fraction was fed at 3% of the diet for 6 weeks followed by 2 weeks with a control diet. Hens were inseminated weekly with .05 ml of pooled semen from males given control diets. The purified water-soluble fraction increased feed consumption during the test periods. During the posttest period, hens fed test diets consumed less feed than those fed a control diet. All test diets did not affect body weight change during the test periods. There was a significant increase in body weight of hens on the diet containing 3% crude culture and a marked decrease in body weight of hens fed the purified water-soluble fraction during the posttest period. Egg production and egg weight were not affected by treatments during the test and posttest periods. Fertility was reduced by the crude culture of F. roseum 'Graminearum' during the 6-week test. Hatchability of fertile eggs was significantly reduced by the purified water-soluble fraction and the crude culture of F. roseum 'Graminearum'. Hatchability rapidly increased when these toxic diets were replaced with control diets. The majority of embryo mortality occurred during 5 days of incubation. The major mycotoxins responsible for reduced hatchability of fertile eggs appeared to be water soluble components of F. roseum 'Graminearum' and not trichothecenes or zearalenone.

Animal Feed↗
PubMed1985

Effects of some motion sickness suppressants on static and dynamic tracking performance.

Two studies examined the influence of three established antimotion sickness drugs on tracking performance in static (stationary) and dynamic (angular acceleration) conditions and on visual fixation ability during motion. In Study I, 40 young men were randomly assigned in equal numbers to either a control (lactose placebo), dimenhydrinate (50 mg), promethazine hydrochloride (25 mg), or mixture (25 mg promethazine plus 10 mg d-amphetamine) group. Study II used 30 new subjects equally divided into control, dimenhydrinate (100 mg), and promethazine (50 mg) groups. Following practice, tests were conducted prior to, and 1, 2, and 4 h after drug ingestion. The depressant drugs had little effect on static tracking, but impaired dynamic tracking performance and reduced ability to maintain visual fixation on a localizer/glide slope instrument due to increased ocular nystagmus. The mixture of promethazine plus d-amphetamine produced none of these deleterious effects.

Aerospace Medicine↗
PubMed1983

The adjective generation technique: consistency of self-description in psychiatric patients.

There has been considerable controversy about whether human behavior is consistent across situations and time. Using the adjective generation technique (AGT), Allen and Potkay (1973, 1977a) found that subjects' self-favorability was quite variable and concluded that this did not support Bem and Allen's (1974) position that the consistency would be greater if idiographic assessment techniques were utilized. Bem (1977) criticized this conclusion, making the points that the AGT is not idiographic and that the favorability value of each day should be considered as a single item in a larger test rather than be considered independently. The present study was designed to address both the consistency of behavior across time and also the controversy regarding the AGT. Eleven psychiatric inpatients completed the AGT for 30 consecutive days. The results indicated that while AGT values are highly variable on a day-to-day basis, these values are quite consistent when averaged across even short periods of time. These results are very similar to those reported by Epstein (1979).

Adult↗
PubMed1982

Comparative evaluation of two MMPI short forms with chemical abusing inpatients.

Studied several novel analyses of the correspondence between two popular MMPI short forms and the full MMPI, including multivariate profile analyses and analyses of change scores. Pre- and posttreatment MMPIs were collected from 100 veterans in a treatment program for alcohol and drug problems. Scores for the Faschingbauer Abbreviated MMPI and the MMPI-168 were extracted from full MMPI protocols. Each short form was compared separately with the full form in several individual-case-oriented and group-data-oriented analyses. Significant differences between full and both short form profiles were found. It was concluded that neither short form is recommended for individual case descriptions, that significant problems arise in using these short forms for group descriptive or comparative research, and that these short forms show moderately acceptable correspondence with full MMPIs over time. It appears that short MMPIs continue to show serious deficits in reliability, i.e., in correspondence with full MMPIs, in spite of recent attempts to demonstrate validity somewhat independent of the full MMPI.

Adult↗
PubMed1982

Factors related to patient attrition from alcoholism treatment programs.

This study focused on an examination of a number of factors which might explain dropout from Veterans Administration inpatient alcoholism treatment programs. The investigation included 137 closed treatment groups that were used at this hospital over a 12-year span. These programs involved five different treatment modalities which varied in treatment length as well as in size of the treatment group. Program directors need to be aware that if their treatment approach involves closed treatment groups, the size of the group, its composition, and the length of the program can influence the dropout rate. According to these results the optimal group size is around five individuals and should not include a large percentage of individuals who are of high intelligence. Dropout rates declined as program length was shortened.

Adult↗
PubMed1982

A comparison of some effects of three antimotion sickness drugs on nystagmic responses to angular accelerations and to optokinetic stimuli.

While the basic efficacy of antimotion sickness drugs is rooted in the reduction of motion sickness symptoms, adverse side effects are important practical considerations of their usage in aviation. This study examined the influence of three established antimotion sickness drugs on nystagmic eye movement responses to angular acceleration (whole-body movement) with vision either permitted or denied, and to optokinetic stimulation (visual field movement). Dimenhydrinate and promethazine hydrochloride, particularly at higher dose levels, reduced optokinetic nystagmus, thereby making less accurate the following ability of the eye. During whole-body motion in darkness, there was little placebo-drug difference in the vestibular response under alert conditions; under relaxed conditions, dimenhydrinate and promethazine hydrochloride produced significant declines in the vestibular eye movements. These same drugs also interfered with the ability of the individual to fixate adequately on a visual task during motion. Subjects who received a combination of promethazine plus d-amphetamine were able to suppress vestibular eye movements and maintain good visual fixation under the task condition. Thus, the effect of a drug on nystagmus may be a poor indicator of its value in preventing motion sickness. Moreover, assessments of antimotion sickness drugs for many practical situations should include, as a possible adverse side effect, the inability to maintain visual fixation during motion.

Acceleration↗