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Biomedical subjects

B H Gray

Publications and source records attributed to B H Gray.

At least 73 records · Page 4Linked to original sources
PubMed1983

Radioprotection by polyethylene glycol-protein complexes in mice.

Polyethylene glycol of about 5000 D was activated with cyanuric chloride, and the activated compound was complexed to each of three proteins. Polyethylene glycol-superoxide dismutase and polyethylene glycol-catalase were each radioprotectants when administered prophylactically to female B6CBF1 mice before irradiation. The dose reduction factor for these mice was 1.2 when 5000 units of polyethylene glycol-catalase was administered before 60Co irradiation. Female B6CBF1 mice administered prophylactic intravenous injections of catalase, polyethylene glycol-albumin, or heat-denatured polyethylene glycol-catalase had survival rates similar to phosphate-buffered saline-injected control mice following 60Co irradiation. Polyethylene glycol-superoxide dismutase and polyethylene glycol-catalase have radioprotective activity in B6CBF1 mice, which appears to depend in part on enzymatic activities of the complex. However, no radioprotective effect was observed in male C57BL/6 mice injected with each polyethylene glycol-protein complex at either 3 or 24 hr before irradiation. The mechanism for radioprotection by these complexes may depend in part on other factors.

Animals↗
PubMed1982

Superoxide dismutase activity in the cochlea.

It was found that superoxide dismutase (SOD) exhibits a higher specific activity in a fraction of the cochlea that contains the organ of Corti than in most other neural tissues. SOD may comprise as much as 4.3% of the soluble protein in this fraction. Approximately 74% of this SOD is cyanide-inhibitable, indicating that it is the Cu/Zn isoenzyme usually found in the cytoplasm. SOD activity was also found in a fraction containing the stria vascularis. Two enzymes that regulate peroxide concentrations, catalase and glutathione peroxidase, were also prominent in both of these fractions.

Animals↗
PubMed1978

Research involving human subjects.

This article reports a study of the activities and performance of institutional review boards to protect human research subjects. Researchers and institutional review board members were generally supportive of the review system, although substantial criticisms were also heard. Institutional review boards had some direct impact on half of the proposals reviewed by requiring either modification of or additional information about proposed research. The data, however, raise questions about the effectiveness of some review board actions, for example, with regard to informed consent. Some policy implications of the study are presented.

Attitude↗
PubMed1977

The functions of human subjects review committees.

After summarizing the literature on the functioning of committees set up to review research involving human subjects, the author describes three latent or emerging functions of these committees. These include using the committees to protect institutions, to judge proposed research in terms of possible social policy impact, and to consider proposed research from the standpoint of "community acceptability". The author expresses concern about the possible politicization of review committee decisions.

Ethical Review↗
PubMed1975

An assessment of institutional review committees in human experimentation.

A study of the functioning of an institutional review committee, when combined with the Barber et al. survey data on 300 institutions, allows for a useful provisional assessment of the strengths and weaknesses of existing procedures for protecting human research subjects. The evidence shows that there is an important role for such committees; however, most committees are relatively permissive. While on committees' performance showed that such committees can have an impact on proposed research, the absence of effective monitoring procedures and lack of feedback from research subjects limits the impact of the review procedure on the actual conduct of research. The question is also raised whether the review procedure, because of its legitimizing functions, may have some regressive consequences for the protection of human subjects.

Clinical Trials as Topic↗
PubMed1973

Phycobilisomes from a blue-green alga Nostoc species.

Phycobilisomes were isolated from a Nostoc sp. strain Mac in phosphate buffer (pH 7.0) by treatment with 1% Brij 56 and centrifugation on discontinuous sucrose gradients (2.0, 1.0, 0.5, and 0.25 M in the proportions 6:4:4:10 ml, respectively). Absorption spectra of isolated phycobilisomes showed the presence of phycoerythrin, phycocyanin, and allophycocyanin. The phycobilisome pigments were partially resolved by electrophoresis on acrylamide gels. Stained gels demonstrated that each main protein band corresponded to a pigmented region. The phycobilisomes appeared compact with a rounded surface and flattened base (about 40-nm diameter) at the attachment site to the photosynthetic lamellae. Fixation in glutaraldehyde caused a significant reduction in total pigment absorption, as well as shifts in the absorption maxima, particularly that of phycoerythrin.

Cell Membrane↗
PubMedDate not supplied

An automated analysis for superoxide dismutase enzyme activity.

The pyrogallol autoxidation assay for superoxide dismutase was adapted for analysis by centrifugal analyzer. The precision of the enzymatic assay was estimated using bovine blood superoxide dismutase. Specific activity determined for human erythrocyte superoxide dismutase by the procedure agreed with previously reported determinations. Recovery of bovine blood superoxide dismutase from hemolysates provided a measure of proportional analytic error. Difficulties inherent in attempting to spectrophotometrically assay an enzyme catalyzing a reaction requiring a free radical substrate cannot be eliminated by an automated method. However, the centrifugal analyzer method makes routine enzymatic analysis for superoxide dismutase in numerous samples technically feasible. Moreover, automated analysis can conveniently include a standard such as bovine blood superoxide dismutase when enzyme levels in tissue extracts are assayed. These advantages make the method for assay of superoxide dismutase enzyme activity a useful procedure.

Centrifugation↗
PubMedDate not supplied

Medical professionalism under managed care: the pros and cons of utilization review.

We contend that the full consequences of managed care for American medicine and health care professionals can be more fully understood if strategies for managing care are identified-in particular, strategies for the administrative oversight of professional decision making. In this paper we apply this perspective to the study of third-party utilization review, making use of a national survey of firms contracting to provide prior authorization for hospitalization in 1992. Survey data suggest that (1) existing approaches to utilization review differ greatly among review firms; (2) review practices that might improve agency and accountability seem to be overlooked by most review firms; and (3) a large number of review firms employ practices that undermine professional autonomy in seemingly inappropriate ways.

Data Collection↗
PubMedDate not supplied

Trust and trustworthy care in the managed care era.

Trust is essential to the doctor/patient relationship, but trust in physicians' fiduciary ethic has become less plausible as a protector of patients' interests. The rise of managed care often is seen as undermining the fiduciary ethic and lessening the trustworthiness of care. But can managed care enhance that trustworthiness? Four possible sources of trustworthiness in managed care are discussed: ethical standards in the managed care industry, nonprofit organizations, physician control, and performance monitoring by purchasers. Limitations on all of these fronts suggest the continuing importance of a strong fiduciary ethic on the part of physicians who make patient care decisions.

Codes of Ethics↗
PubMedDate not supplied

Conversion of HMOs and hospitals: what's at stake?

Because for-profit conversions of nonprofit organizations are regulated under trust law at the state level, their health policy implications have generally not been part of the process. This paper provides a health policy framework for assessing conversions of hospitals and health maintenance organizations (HMOs). It begins with basic differences in ownership forms and identifies considerations on both sides of the conversion question. The analysis turns on the extent of the social benefits of nonprofits: the regulatory tool provided by tax exemptions, trustworthiness in the presence of informational asymmetries, and community benefit activities. The analysis and the evidence suggest that the nonprofit form continues to hold significant advantages in health care that bear consideration by policymakers faced with conversion proposals.

Health Facility Merger↗
PubMedDate not supplied

Safety-net health plans: a status report.

This paper reports on a national survey of Medicaid managed care plans sponsored by safety-net provider organizations that have a mission of service to low-income populations. We identified ninety-nine safety-net plans and obtained data from eighty of them regarding their sponsorship, age and size, relationships to sponsors, managed care practices, and measures of success. Most plans engage in active managed care and have achieved at least some of their goals. However, 60 percent of plans lost money in 1997, and economic trends have been unfavorable.

Financial Management↗