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Biomedical subjects

R K Morgan

Publications and source records attributed to R K Morgan.

16 recordsLinked to original sources
PubMed2001

Single-participant research design. Bringing science to managed care.

The ongoing transition to managed health care continues to have repercussions for health care providers, perhaps the most important of which is an emphasis on accountability for demonstrating the usefulness of clinical interventions. This requirement places a premium on intervention research and highlights the historically strained relationship between psychological research and professional practice. In the midst of this challenge, researchers have increasingly criticized the logic and practice of traditional null hypothesis significance testing. This article describes the history, epistemology, and advantages of single-participant research designs for behavioral scientists and professionals in clinical settings. Although its lack of correspondence with the Fisherian tradition has precluded widespread adoption, the single-participant alternative features a design power and flexibility well suited to both basic science and applied research.

Behaviorism↗
PubMed1998

Bioethics education in a clinical pastoral education program.

Notes that contemporary health care delivery and the interface of clinical professionals with patients and families are marked by complexity and pluralism and that within this modern matrix patients, families, professionals, and administrators frequently struggle with difficult ethical issues. Observes that these realities have significant implications for chaplains and for chaplains-in-training, a factor which has received the attention of the Bioethics Committee of the Professional Chaplains Association through its Bioethics Committee and resulting in a set of guidelines for the chaplain's appropriate roles in bioethical issues and for their role on bioethics committees. Describes the establishment of a bioetchics modulate at the Cleveland Clinic Foundation (CCF) in which chaplain residents are enabled to function as professional peers with other healthcare professionals and as competent chaplains with patients and families in bioethical decision making. Reports on the methods and the results of a pilot study based on the model described.

Chaplaincy Service, Hospital↗
PubMed1994

Viscoelastic-related glaucomas.

The routine surgical use of viscoelastic substances has revolutionized many anterior segment procedures. All of the currently available agents may be responsible for causing or exacerbating a transient, but occasionally significant, postoperative IOP elevation. In spite of differences in physical properties such as molecular weight, concentration, and viscosity, none of the various viscoelastics has consistently shown a decreased likelihood of producing ocular hypertension. Moreover, any newly introduced product must be evaluated carefully for this potential complication. Lavage of viscomaterial from the anterior chamber and administration of ocular antihypertensives may be helpful in averting or controlling the increased IOP. The surgeon should be cognizant of any pre-existing optic nerve damage and adjust the aggressiveness of postoperative glaucoma therapy accordingly. In the future, the development of new substances or simultaneous use of degrading enzymes may reduce or eliminate the incidence of viscoelastic-induced ocular hypertension.

Animals↗
PubMed1991

Statpac 2 glaucoma change probability.

We compared the traditional intuitive criterion (fixed at 5 dB) with the variable Statpac 2 criterion of the Humphrey Field Analyzer for identifying visual deterioration at individual points within a visual field. The separation of depressed from stable points in 123 follow-up fields of 17 patients, when all points within a field were considered, was reasonably equivalent between the two methods (kappa = 0.55 +/- 0.027 [+/- SE]). Centrally located points within the field demonstrated a stronger agreement (kappa = 0.68 +/- 0.028), because the fixed criterion more often labeled the edge points as having progressed than did the Statpac 2 algorithm. The glaucoma change probability printout is more simply obtained than the manual comparison required for intuitive interpretation with a fixed criterion, and it is potentially more accurate because of its reliance on a database that permits a variable criterion to be applied.

Aged↗
PubMed1990

Psychological symptoms in primary fibromyalgia syndrome: relationship to pain, life stress, and sleep disturbance.

Twenty-five subjects with primary fibromyalgia syndrome and 22 subjects with rheumatoid arthritis were compared on measures of psychological distress, pain, health status, life stress, sleep disturbance, and coping strategies. Higher levels of psychological distress were found in the primary fibromyalgia syndrome group, but the degree of life stress was shown to be a significant covariate.

Adaptation, Psychological↗
PubMed1987

A comparative evaluation of heart rate reactivity during MATH and a standard mental arithmetic task.

Heart rate was monitored while 20 young males completed MATH, a computer-operated mental arithmetic task specifically designed for use in experiments involving subjects of heterogeneous numerical ability, and a standard mental arithmetic task used in this laboratory on several occasions. Both tasks elicited sizeable increases in heart rate, and comparison of subjects' reactivity scores revealed significant inter-task consistency of reaction.

Adult↗
PubMed1986

Graded mental arithmetic as an active psychological challenge.

A computer-operated mental arithmetic task is outlined which presents questions at a level of difficulty continuously determined by subjects' accuracy of response on the previous question. The programme incorporates 5 levels of difficulty, and all questions concern the addition or subtraction of two numbers which vary in digit-span according to the current level of difficulty. Response requirements are manual rather than verbal so that, in addition to monitoring heart rate, subjects' exhaled air may be collected throughout the task in order to determine oxygen consumption.

Computers↗
PubMed1985

Voluntary alteration of pattern visual evoked responses.

Pattern and flash visual evoked responses (VERs) were recorded from a large group of ophthalmologically normal subjects during two conditions: in one they were instructed to attend to the stimulus and in the other they were instructed to ignore the stimulus but maintain their gaze on the stimulus. Pattern VERs were recorded from 42 subjects. Fixation was constantly monitored during both attend and ignore conditions and no changes of fixation were noted at any time. The amplitude of the major positive wave of the pattern VERs produced by both 50- and 25-min checks was reduced significantly during the ignore condition. The implicit time of this positive wave did not differ significantly during the two conditions. The pattern VERs of eight subjects were extinguished and the VERs of another three subjects were unrecognizable during the ignore condition. Flash VERs produced by 10 flashes per second were recorded from 38 of the 42 subjects. There were no significant differences between the amplitudes recorded during the attend and ignore conditions.

Adult↗
PubMed1981

Bernard-Soulier disease: a study of four patients and their parents.

Two families with Bernard-Soulier disease, including four patients and three of their parents, were studied and detailed clinical summaries are presented. One patient in each family has suffered severe bleeding problems while the other affected sibling is less severely affected. There has been no excessive bleeding in any of the parents or other family members. The patients demonstrated the abnormalities characteristic for Bernard-Soulier disease: thrombocytopenia, giant platelets, prolonged bleeding time, abnormal platelet aggregation to human FVIIIvWF and ristocetin or bovine FVIIIvWF alone, defective ristocetin-induced binding of human 125I-FVIIIvWF multimers, decreased platelet lysis by a drug-dependent antibody and complement, and a decreased concentration of membrane glycoprotein I. The parents had normal platelet counts, bleeding times, and FVIII-mediated aggregation. However, the parents had abnormally large platelets decreased sensitivity to lysis by a drug-dependent antibody and complement, and a decreased concentration of membrane glycoprotein I. Therefore the heterozygous state for Bernard-Soulier disease is recognizable by platelet membrane abnormalities although there is no defect of platelet function and no excessive bleeding. Red cell membrane proteins of one patient were normal, suggesting that phenotypic expression of the Bernard-Soulier disease defect is restricted to platelets.

Adolescent↗
PubMed1981

Variation in haematological parameters among inbred strains of rat.

Haematological determinations were carried out on 7 inbred strains of rats using a standardized procedure. Significant genetic variation was found for many of the parameters although none of the strains had values which could be termed pathological. Measurements also varied significantly from day to day. Factorial analysis of variance is shown to be a powerful method for the investigation of variation in haematological parameters.

Analysis of Variance↗
PubMed1980

Membrane changes associated with platelet activation. Exposure of actin on the platelet surface after thrombin-induced secretion.

The effect of aggregation and secretion on membrane proteins was studied in washed human platelets. Reversible aggregation without secretion was stimulated by ADP and secretion without aggregation was stimulated by thrombin in the presence of EDTA. No loss of platelet surface glycoproteins occurred during reversible ADP-induced platelet aggregation, as measured by quantitative polyacrylamide gel electrophoresis analysis of platelets that were labeled with (125)I-diazotized diiodosulfanilic acid (DD(125)ISA) before ADP stimulation. Also, no new proteins became exposed on the platelet surface after ADP aggregation, as determined by DD(125)ISA labeling after stimulation. Thrombin-induced platelet secretion also caused no loss of platelet surface glycoproteins. However, after platelet secretion two new proteins were labeled by DD(125)ISA: (a) actin and (b) the 149,000-mol wt glycoprotein (termed GP-G), which is contained in platelet granules and secreted in response to thrombin. The identity of DD(125)ISA-labeled actin was confirmed by four criteria: (a) comigration with actin in three different sodium dodecyl sulfate-polyacrylamide gel electrophoresis systems, (b) elution from a particulate fraction in low ionic strength buffer, (c) co-migration with actin in isoelectric focusing, and (d) binding to DNase I. The identity of actin and its appearance on the platelet surface after thrombin-induced secretion was also demonstrated by the greater binding of an anti-actin antibody to thrombin-treated platelets, measured with (125)I-staphylococcal protein A.Therefore, major platelet membrane changes occur after secretion but not after reversible aggregation. The platelet surface changes occurring with secretion may be important in the formation of irreversible platelet aggregates and in the final retraction of the blood clot.

Actins↗