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Biomedical subjects

D Callahan

Publications and source records attributed to D Callahan.

At least 37 records · Page 2Linked to original sources
PubMed1991

Evaluating the Oregon priority plan.

The Oregon priority plan represents an innovative method of reforming its Medicaid program. It would replace the present system of limiting the number of people in the program with one that would, after setting priorities, limit treatment benefits. The strength of the plan is that it would provide all the poor with health care coverage; its potential drawback is that it might put expectant mothers and children at a disadvantage and possibility make some forms of needed care inaccessible to other groups as well. Despite the drawbacks and uncertainties of the priority plant, it deserves to be given a chance to prove itself.

Evaluation Studies as Topic↗
PubMed1990

Must the old and young compete for health care resources?

The number of older persons in our society is increasing as the number of younger persons decreases. Expenditures on the young are decreasing and those on the elderly are increasing. Questions relating to the decisions that may be made in the process of allocation of resources for these competing groups are examined in detail. The goal of meeting all individual needs may well require setting "reasonable" limits and fashioning a broader societal perspective.

Aging↗
PubMed1990

Current trends in biomedical ethics in the United States.

Enormous growth of medical activities and issues in the 1960s and 1970s stimulated birth of the field of contemporary biomedical ethics. Nevertheless, when one examines recent trends within the field in the United States, one is struck with how many significant transformations and developments have occurred since that time. This presentation examines recent developments in five areas--those of patient rights and autonomy, termination of life, manipulation of Nature, health care resource allocation, and decision-making by the general public. The author also notes that although bioethical issues have become politicized as major interest groups and the general public have become increasingly involved, the quest for consensus remains a central one for health care ethics in the United States.

Bioethical Issues↗
PubMed1989

Quantitative immunofluorescence assay for cyclobutyldithymidine dimers in individual mammalian cells.

An indirect immunofluorescence procedure was developed for the measurement of cyclobutyl dithymidine dimers in DNA of individual Syrian hamster embryo cells using a specific monoclonal antibody. A fluorescein-labeled secondary antibody and a fluorochrome which binds to DNA were used to measure the photoproduct and total DNA in the same nucleus. Fluorescence intensity was quantitated with a computer-assisted microfluorometric system which was calibrated with a uranyl oxide impregnated glass slide. Similar dose-response curves, i.e. normalized fluorescence intensity plotted as a function of dose of germicidal irradiation, were obtained with two different cell types. Normalized fluorescence intensity per nucleus was related to thymidine dimer content with a competitive enzyme-linked immunosorbent assay using DNA isolated from cells given doses of germicidal irradiation identical to those used in the immunofluorescence assay. Thymidine dimer levels produced by 10 J/m2 of germicidal irradiation (approximately 8 x 10(5)/nucleus) and which allow for 15-30% cell survival can readily be detected. The specific monoclonal antibody was labeled with tritium and used in the immunofluorescence assay to relate the number of antibodies bound to the number of thymidine dimers per cell. The data revealed that approximately 45% of the thymidine dimers in cells exposed to 100 J/m2 of germicidal irradiation and essentially all the T mean value of T in cells receiving 20 J/m2, were being detected in the indirect immunofluorescence assay. This technique can provide a sensitive means for measuring various types of DNA damage in individual cells given that the appropriate probes are available. It can be especially useful for monitoring occupationally or environmentally exposed populations where usually only small samples of cells or tissues are available.

Animals↗
PubMed1988

New transurethral system for interstitial radiation of prostate cancer.

Direct endoscopic implantation of radioactive materials for carcinoma of the prostate without an open operation was accomplished by the use of modified existing transurethral instrumentation and techniques. The closed approach seems applicable particularly to the geriatric population, which is afflicted more commonly but is frequently not treated because of concurrent diseases or because the patient had transurethral resection of the prostate as a diagnostic procedure. Eleven patients were implanted using the transurethral route. Implantations were accomplished successfully with extremely low morbidity. Along with more conventional dosimetry studies, computer tomography was used to assess the placement of seeds. The direct visualization of the method suggests a potential for greater precision of seed placement as illustrated by computer tomography. In addition, this new instrumentation and method offers a low-risk procedure for carcinoma of the prostate that can be performed on an outpatient basis for selected patients.

Aged↗