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Biomedical subjects

M Boyd

Publications and source records attributed to M Boyd.

At least 73 records · Page 4Linked to original sources
PubMed1991

Pyrazole analogues of the bispyrrolecarboxamide anti-tumour antibiotics: synthesis, DNA binding and anti-tumour properties.

Four bispyrazole compounds have been prepared as potentially more stable analogues of the DNA minor groove binding polypyrrole compounds netropsin and distamycin, which are susceptible to oxidative breakdown. These compounds bind less strongly to DNA, and show much lower specificity for binding to AT-rich DNA sequences in comparison with distamycin. N.m.r. studies show that two of these compounds cause a downfield shift of the DNA imino proton resonances on interaction with the oligonucleotide d(ATATATATAT)2, suggesting that these isomers can adopt low-energy conformations similar to that shown by distamycin in its DNA minor groove binding site. The benzoic acid mustard analogue of one of the minor groove binding bispyrazoles was prepared, and showed in vitro cytotoxicity comparable with that of the previously-reported distamycin mustard, but only a low level of activity in vivo.

Amides↗
PubMed1990

NMR studies of configuration and tautomeric equilibria in nitroacridine antitumor agents.

The solution configurations of the 1-nitroacridine nitracrine (a clinically used anticancer agent and experimental hypoxia-selective cytotoxin) and its nitro isomers were determined, an both free bases in CDCl3 and as monocations (chromophore free base) and dications in D2O, by high-resolution proton magnetic resonance spectroscopy. The free bases of the 1-, 2-, and 3-nitro isomers exist in the aminoacridine configuration in CDCl3, while the 4-nitro isomer appears to exchange slowly between the aminoacridine and iminoacridan configurations. As cations at pH 2 in D2O, all four isomers exist in the aminoacridine configuration. When the pH is increased to 7-8 to form the free bases of the nitroacridine chromophores, the 2- and 3-nitro isomers retain the aminoacridine configuration, but the 1- and 4-nitro isomers convert to the iminoacridan configuration. These results are relevant to the ongoing discussion of aminoacridine-iminoacridan tautomerism of these acridine derivatives in solution.

Aminoacridines↗
PubMed1990

Theory Z as a framework for the application of a professional practice model in increasing nursing staff retention on oncology units.

Recruitment and retention of nurses is the most significant issue facing nursing administrators, educators, researchers and clinicians in the ongoing nursing shortage in the United States today. It has been cited in the literature that American nurses feel that job satisfaction is a major issue in retaining qualified nurses in hospitals. Satisfaction occurs when nurse expectations are matched with the hospital's vision and values. It is for this purpose that the authors have chosen theory Z as a hospital management model to coincide with the institution of the Marker Professional Practice Model to increase job satisfaction (autonomy) in hospital-based nurses. There are four 'hidden' challenges in health care today. They are: (a) fundamental changes occurring within the profession and practice of nursing; (b) the expanded role of women in management; (c) ethical dilemmas related to advances in medical technologies; and (d) the difficulty for health care managers in the United States to make changes related to the above three challenges. The authors feel that it is inherent to the nursing profession to combine existing theories and models to enhance the retention of nurses to the profession.

Hospital Units↗
PubMed1989

Cervical spinal deformity following craniotomy and upper cervical laminectomy for posterior fossa tumors in children.

Spinal deformity is not usually regarded as a potential complication of posterior fossa tumor resection. After cervical subluxation had been recognized in 2 children following removal of posterior fossa tumors, a review was carried out to determine the incidence of this complication. Of the 72 children who had undergone resection of a posterior fossa tumor, 4 patients, including the original 2, developed a cervical spinal deformity. Factors that predisposed to this complication included laminectomy of C2 or lower, local wound complications and possibly post-operative neck weakness. It is important to be aware that cervical subluxation can occur after resection of posterior fossa tumors, when laminectomy extending below C1 has been performed. Patients at risk should be followed closely.

Brain Neoplasms↗
PubMed1989

Family and personal networks in international migration: recent developments and new agendas.

Family, friendship, and community networks underlie much of the recent migration to industrial nations. Current interest in these networks accompany the development of a migration system perspective and the growing awareness of the macro and micro determinants of migration. This article presents an overview of research findings on the determinants and consequences of personal networks. In addition, it calls for greater specification of the role of networks in migration research and for the inclusion of women in future research.

Communication↗
PubMed1988

Diffuse well-differentiated lymphocytic lymphoma: chemotherapy with BCNU, cyclophosphamide, vincristine, melphalan and prednisone.

Twenty patients with stage III and IV diffuse well-differentiated lymphocytic lymphoma were treated with combination chemotherapy consisting of BCNU, cyclophosphamide, vincristine, melphalan and prednisone (M-2). Treatment was given every 5 weeks for 11 cycles in responding patients. The median age of the patients was 62 years (range 45-76). There were 12 complete remissions and 6 partial remissions for an overall response rate of 90%. The median duration of remission was 24 months (range 12-79 months) and was identical for complete responders and partial responders. All but 2 responding patients have been subsequently retreated for relapse. The median survival was 84 months (range 1-108 months). Myelosuppression was mild. Nausea/vomiting, neuropathy, alopecia and gastrointestinal symptoms from prednisone were seen in the minority of patients. One patient expired from sepsis/neutropenia during the first cycle of therapy. The M-2 protocol produces effective remissions in diffuse well-differentiated lymphocytic lymphoma. The relapse and survival pattern are similar to the results achieved with other chemotherapy regimens in low-grade lymphoma.

Adult↗
PubMed1987

Microencapsulated tumor assay: new short-term assay for in vivo evaluation of the effects of anticancer drugs on human tumor cell lines.

A new in vivo has been developed for evaluating the antitumor activity of chemotherapeutic drugs. The assay is based on a microencapsulation technology developed by Damon Biotech, Inc., Boston, MA, which makes it possible to encapsulate human tumor cells in small (about 1 mm in diameter) microcapsules with semipermeable membranes. Microcapsules containing human tumor cells were injected i.p. into nude or C57BL/6 mice and drugs were administered i.v. The microcapsules were recovered at various intervals following treatment and determinations of drug effects were made based on the differences in the number of tumor cells recovered from the treated and nontreated animals. Using this assay we found that (a) encapsulated tumor cells grew better in the in vivo system than in vitro under the conditions tested; (b) drugs crossed the capsular membrane and killed or inhibited the proliferation of tumor cells; and (c) the antitumor effect was consistent with the relative therapeutic efficacy of drugs or level of resistance of tumor cells detected by other in vitro or in vivo tests. The tumor microencapsulation assay offers several properties which make it attractive for use in new drug development: (a) the antitumor activity of drugs can be tested against human tumor cells under conditions which provide for three-dimensional growth and in vivo supply of nutrients; (b) the sensitivity of tumor cells can be assessed following exposure to drugs at concentrations which are achievable in vivo; (c) compounds requiring in vivo metabolic activation can be tested; (d) the effect of each drug injection can be quickly evaluated; (e) inhibition of tumor cell proliferation versus cytoreductive effects of drugs can be discriminated; (f) the test is applicable to virtually all histological types of human tumor cells; and (g) the tumor microencapsulation assay is a short-term, simple, and relatively inexpensive assay.

Animals↗
PubMed1986

Temporary workers in Canada: a multifaceted program.

"This article highlights important developments in the character of temporary worker flows to Canada between 1973 and 1985 through the use of unpublished data and new measures for analyzing this data. The number of employment authorizations are converted to person years to indicate the overall labor market impact of temporary worker flows and this measure is employed in an analysis of unpublished data from Employment and Immigration Canada. The analysis reveals that a significant and growing proportion of employment authorizations are exempted from governmental procedures which link the admission of temporary workers to the Canadian labor market." Reasons for these exemptions and policy implications are discussed

Americas↗
PubMed1981

Filterability and vascular disease--II. Red cell filterability after myocardial infarction.

Red cell filterability was measured in 51 patients after proven myocardial infarction. The filterability index (FI) falls to a minimum 7-16 h after the onset of symptoms. This early minimum value is a very good indicator of the patients' subsequent clinical course. The results of three different types of experiments all suggested that the changes in FI were principally due to a change in the plasma secondarily affecting the red cells.

Blood Viscosity↗
PubMed1981

The American emigrant in Canada: trends and consequences.

"This article discusses the nature of out-migration from the United States to Canada and assesses the consequences of such emigration for the two countries. It is concluded that, excluding the British born population, being foreign born is a handicap in Canada, not as asset, and the American born overcome this occupational disadvantage by virtue of their higher social origins and education."

Americas↗