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Biomedical subjects

C Weijer

Publications and source records attributed to C Weijer.

At least 55 records · Page 3Linked to original sources
PubMed1997

Bioethics for clinicians: 10. Research ethics.

Medical research involving human subjects raises complex ethical, legal and social issues. Investigators sometimes find that their obligations with respect to a research project come into conflict with their obligations to individual patients. The ethical conduct of research rests on 3 guiding principles: respect for persons, beneficience, and justice. Respect for persons underlies the duty to obtain informed consent from study participants. Beneficence demands a favourable balance between the potential benefits and harms of participation. Justice requires that vulnerable people not be exploited and that eligible candidates who may benefit from participation not be excluded without good cause. Studies must be designed in a way that ensures the validity of findings and must address questions of sufficient importance to justify the risks of participation. In any clinical trial there must be genuine uncertainty as to which treatment arm offers the most benefit, and placebo controls should not be used if effective standard therapies exist. Researchers have a responsibility to inform themselves about the ethical, legal and policy standards that govern their activities. When difficulties arise, they should consult the existing literature and seek the advice of experts in research ethics.

Beneficence↗
PubMed1997

Twisted scroll waves organize Dictyostelium mucoroides slugs.

Cellular slime moulds (Dictyosteloids) are characterised by at least two different modes of slug migration. Most species, e.g. Dictyostelium mucoroides, produce a stalk continuously during slug migration, while a few species, e.g. Dictyostelium discoideum are characterised by stalk-less slug migration and only produce a stalk upon culmination. Experiments on D. discoideum and theoretical model calculations have shown that D. discoideum slugs are organized by a cAMP scroll wave in the tip which produces planar waves in the back. These waves guide cell movement in slugs: spiralling in the tip and forward movement parallel to the slug axis in the back. Simple changes in model parameters can lead to the formation of a twisted scroll wave which extends throughout the slug. In order to investigate whether such twisted scroll waves occur naturally we have analysed the movement of fluorescently labelled single cells in migrating D. mucoroides slugs. The results show that cells in the prespore zone of D. mucoroides slugs move in a spiral path. Although the velocity of single cells in D. mucoroides is faster than in D. discoideum, the net forward component of their movement is less due to their spiral trajectories. As a result D. mucoroides slugs move more slowly than D. discoideum slugs. The entire D. mucoroides slug also describes a spiralling path leaving corkscrew shaped stalks behind. Based on these observations we propose that cell movement in D. mucoroides slugs is controlled by a propagating twisted scroll wave of cAMP which extends throughout the length of the slug.

Animals↗
PubMed1997

Do patients with breast cancer participating in clinical trials receive better nursing care?

PURPOSE/OBJECTIVES: To examine differences in nursing care received by patients with breast cancer enrolled in clinical trials and those not enrolled in clinical trials. DESIGN: Retrospective review of clinic charts. SETTING: Oncology outpatient department of a tertiary-care hospital. SAMPLE: 90 women with early stage breast cancer. The mean age of the women was 53 years. More than half of the women (51 of 90) were treated in a clinical trial. METHODS: Retrospective chart review of all the nurse-patient clinic encounters for a six-month period from date of cancer diagnosis. The content of each encounter was coded using a modified version of the Nursing Action Classification System. MAIN RESEARCH VARIABLES: Nursing interventions (i.e., assessment, medical scheduling, psychosocial scheduling, reassurance, and teaching) and phone calls. FINDINGS: Women enrolled in clinical trials had more phone interactions with nursing staff (p = 0.003) and received teaching (p < 0.001) and reassurance (p = 0.005) from nursing staff more often than women not enrolled in clinical trials. Controlling for age and stage of disease, teaching (p < 0.001), and reassurance (p = 0.10) were the primary differences in nursing care between the patients enrolled in clinical trials and those not enrolled. CONCLUSION: Differences in nursing care received exist between patients with breast cancer enrolled in clinical trials and those not enrolled. IMPLICATIONS FOR NURSING PRACTICE: Both teaching and reassurance are important components of caring for patients with cancer and are associated with treatment compliance. If the results of this study are confirmed, measures must be employed to ensure that all patients receive optimal care.

Adult↗
PubMed1996

What difference does it make to be treated in a clinical trial? A pilot study.

OBJECTIVE: Pilot study to characterize treatment differences between patients treated in clinical trials and those treated in a clinical setting. Previous studies have shown higher survival rates for participants in trials of cancer therapy. This difference is observed even after rates are adjusted for important covariates such as age and stage of disease. DESIGN: Retrospective chart review. SETTING: Oncology outpatient department in a tertiary care hospital. PATIENTS: Ninety women 18 to 70 years of age with early-stage breast cancer who were diagnosed in 1990. Fifty-one of the women were treated through clinical trials and 39 were treated outside of clinical trials. OUTCOME MEASURES: Number of blood tests, telephone calls, clinic visits and imaging procedures as well as intensity of chemotherapy and use of radiation therapy. The age of the patient and the stage of disease were important covariates. RESULTS: After the analysis was controlled for patient age and stage of disease, patients treated through a clinical trial were more likely to receive standard-dose chemotherapy (p = 0.020, 95% confidence interval 1.20 to 200.73) and more frequent blood tests (p < 0.001, 95% confidence interval 1.02 to 1.13) than other patients treated in the clinic. CONCLUSIONS: Our results provide a plausible mechanism for the observed survival advantage for participants in clinical trials in oncology. Further study is called for. If these results are confirmed, they have important implications for informed consent to participate in clinical trials and for clinical practice.

Adolescent↗
PubMed1995

Monitoring clinical research: an obligation unfulfilled.

The revelation that data obtained for the US-based National Surgical Adjuvant Breast and Bowel Project (NSABP) from subjects enrolled at Hôpital Saint-Luc in Montreal was falsified has eroded public trust in research. Institutions can educate researchers and help prevent unethical research practices by establishing procedures to monitor research involving human subjects. Research monitoring encompasses four categories of activity: annual reviews of continuing research, monitoring of informed consent, monitoring of adherence to approved protocols and monitoring of the integrity of data. The authors describe characteristics of research projects that may call for monitoring procedures in each category. The form taken by such monitoring depends on the nature of the protocol. Although appropriate research monitoring requires substantial investment of personnel and financial resources, it is required under guidelines regulating research involving human subjects in Canada. Research monitoring is a step forward in re-establishing public confidence in medical research.

Canada↗
PubMed1995

The breast cancer research scandal: addressing the issues.

The three claims put forward by Dr. Roger Poisson to rationalize his enrollment of ineligible subjects in clinical trials do not justify research fraud. None the less, certain lessons for the conduct of clinical research can be learned from the affair: experimental therapies should be made available to technically ineligible subjects when no effective therapy exists for their disease; further research must investigate the possible benefits of clinical-trial participation; broadly based, pragmatic trials must be regarded as the ideal model; and each eligibility criterion in a clinical-trial protocol should be justified.

Bias↗
PubMed1994

Patterns of cell movement within the Dictyostelium slug revealed by cell type-specific, surface labeling of living cells.

There are cells scattered in the rear, prespore region of the Dictyostelium slug that share many of the properties of the prestalk cells and that are therefore called anterior-like cells (ALCs). By placing the gene encoding a cell surface protein under the control of an ALC-specific promoter and immunologically labeling the living cells, we analyze the movement of ALCs within the slug. There is a posterior to anterior cellular flow, and the ALCs change their movement pattern as they enter the prestalk zone. Prestalk cells are periodically shed from the migrating slug. They must be replaced if the correct ratio of prestalk to prespore cells is to be maintained, and we present evidence for the transdifferentiation of prespore into prestalk cells, with ALCs functioning as intermediates in the transition. The slug has, therefore, a surprisingly dynamic structure, both with respect to cellular differentiation and cell movement.

Amino Acid Sequence↗
PubMed1994

The duty to exclude: excluding people at undue risk from research.

The clinical trial is the major investigational tool of clinical medicine. Two recent reports highlight the fact that the most often quoted mechanisms for the protection of research subjects, viz., research ethics board review and eligibility criteria, are insufficient to achieve this end. In this paper, we argue that the prime mechanism for the protection of persons in clinical trials should be the clinical judgement of the physician-investigator. The clinical investigator has a duty to protect subjects from both harm and undue risk. It is argued that the clinical investigator has a duty to screen for, and exclude, potential research subjects who may be unduly vulnerable to the risks of a particular clinical trial. In order to fulfill this obligation, the investigator should personally screen each potential research subject at the time of accrual. In larger trials in which this is not feasible, this task could be delegated to another appropriately qualified health care professional, with the principal investigator retaining personal responsibility. To reinforce and make explicit this legal and moral duty, we propose that the investigator sign a statement, appended to each subject's consent form, to attest that this duty has been responsibly discharged.

Adult↗
PubMed1993

Case notes and charting of bioethical case consultations.

In summary, the usual elements of a typical health care ethics consultation note might reasonably accommodate the needs and expectations of relevant parties, and would therefore include: 1. identification of the relevant ethical issues, questions, or dilemmas; 2. reference to any relevant facts--medical, nursing, social, psychological, spiritual, legal, political, etc.; 3. a prioritized list of recommendations to improve coordinated care; 4. a clear and concise articulation of relevant arguments, wtih specific reference to the list of recommendations as well as to the institution's overall ethos; 5. a contextual statement, identifying the perceived degree of consensus or support for the recommendations and conclusions, as well as any inherent agendas.

Canada↗