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Biomedical subjects

C Worthington

Publications and source records attributed to C Worthington.

At least 19 recordsLinked to original sources
PubMed2000

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗
PubMed1998

Community pharmacist perspectives on HIV/AIDS and interventions for injection drug users in Canada.

In several countries, community pharmacies play a major role in the provision of HIV prevention services to injection drug users (IDUs). In this study, results from a national Canadian Survey of Community Pharmacies and HIV/AIDS Prevention are used to describe pharmacists' perspectives on HIV/AIDS and services to IDUs, and explore the relationship between personal and organizational characteristics and the level of support for HIV/AIDS prevention initiatives. A mailed questionnaire was directed to a random sample of 2,017 pharmacist owner-managers. The response rate was 84.6%. Results suggest that current services to IDUs primarily are limited to discretionary needle and syringe sales to non-diabetics, with almost three-quarters supportive. Staff safety was an important consideration in the provision of this service (77%), while remuneration was the lowest (27%). Community pharmacists were most comfortable with the provision of counselling, advice and literature (X = 2.6) and environmental and technological interventions (X = 2.4) and least supportive of provision of services as part of a programme (X = 1.6) and legalization of drugs or prescription of methadone (X = 1.9). Female pharmacists were more likely to support preventive measures such as the provision of counselling or advice, and males were more likely to promote legislative change. Pharmacists appear generally willing to expand their services in the fight against HIV/AIDS. However, it is not feasible to expect uniform programmes to be immediately introduced. While organizational, educational and policy changes may facilitate programme development, individual pharmacy and pharmacist discretion remains important.

Canada↗
PubMed1997

Comparison of functional magnetic resonance imaging for language localization and intracarotid speech amytal testing in presurgical evaluation for intractable epilepsy. Preliminary results.

A comparison is made between the results of standard intracarotid speech amytal testing and a new methodology, echoplanar blood-oxygen-level-dependent functional magnetic resonance imaging (BOLD fMRI), in patients undergoing presurgical evaluation for intractable epilepsy. Of the 15 patients entered in the study, all had fMRIs while performing a verbal fluency task. Twelve of these patients also underwent standard intracarotid sodium amytal testing for speech and memory. Results of the fMRIs as compared to the intracarotid speech amytal testing are discussed, including agreement and disagreement between studies. Potential reasons for poor concordance are discussed, including complexity of the verbal fluency task, and motion and technical issues in MRI scan acquisition and data analysis.

Adolescent↗
PubMed1996

The role of policy in community pharmacies' response to injection-drug use: results of a nationwide Canadian survey.

The response rate to this survey reflects the salience of the topic and the professional concern about and interest in issues presented by HIV. The HIV/AIDS epidemic has presented pharmacists with one of the greatest challenges to their professional training, ethics, and practice. It further expedites a current re-examination that is occurring among community pharmacies concerning their roles in community health practices. In response to HIV there have been dramatic and unprecedented changes in pharmacy policy and practices. Clearly, some community pharmacies have led the way and influenced policy and practices. In view of the recent introduction of many of these policies and practices, it is likely that change will continue. Survey respondents were, in general, very comfortable with an expanded role involving counseling, health promotion, and disease prevention, consistent with a broader role for community pharmacies in general that has been recently advocated. Community pharmacies serve all areas of the country, in communities large and small; many are open seven days a week, and some provide extended hours of service. Community pharmacies may provide an important complement to community outreach programs as a source of clean needles and syringes for IDUs in most communities, and as an alternative service in some communities where more elaborate programs are not feasible. Safer needle use, as part of a health-promotion approach, is divergent from conventional practice. While major changes have occurred, it appears that there has been some polarization of attitudes and response. The explanation for this is not simple, and further analysis is required to determine the full impact from several ethical perspectives that include professional, business, and public health viewpoints. We have highlighted the role that policy has in moving toward preventive and harm-reduction approaches. From a policy perspective, we have found that support from the federal government, regulatory bodies, and professional associations may be an important catalyst to pharmacists' participation in programs. Further, it does not appear to be possible to implement such policies without professional development and continuing education, and collaboration with the community. Based on data on knowledge and educational need, we believe that our study population's lowest levels of information were in such areas as the role of methadone in HIV prevention and the availability of needle-exchange programs. As with other health-promotion campaigns, additional skills training may be important. Movement forward with expanded preventive and harm-reduction strategies by pharmacies will require careful planning. It is anticipated that change in this area will be incremental in nature, and that it is necessary to introduce programs and services into community pharmacies gradually. Successful implementation will require extensive community development and collaboration with other health professionals, public health officials, police, groups who represent IDUs, and persons living with HIV/AIDS. Careful monitoring and evaluation of these programs will be necessary to enhance their effectiveness.

Canada↗
PubMed1995

The multiconstituency approach to organizational performance assessment: a Canadian mental health system application.

This papers applies a multiconstituency approach to assessing organizational performance in Canadian general hospital psychiatric units and provincial psychiatric hospitals. In the absence of reliable and valid outcome measures, researchers and administrators have increasingly considered the views of external constituencies as a means of both defining the criteria for effective performance and actually assessing organizational performance. Key constituencies included psychiatric unit staff, psychiatric hospital administrators, and directors of community agencies providing mental health and related services. Opinions about organizational roles were found to exist among constituencies and among professional groups. Perceptions of organizational performance were highest for primary roles and substantially lowest for roles of secondary importance to the constituency. Future analyses of this type could help to validate the use of both constituency measures and more traditional performance measures. While constituency views may be seen as subjective, they are nevertheless key to building effective mental health service delivery systems.

Canada↗
PubMed1992

An examination of factors influencing the diagnosis and treatment of black patients in the mental health system.

The Civil Rights Movement, which began in the 1950s and lasted through the mid 1970s played a major role improving the quality of life for black Americans. Although much has changed since the 1950s the roots of racism are deep and change occurs slowly. Race exerts an overwhelming influence on popular ideology and medical thinking. Many researchers have speculated that a strong association exists between race and diagnosis. Understanding the sociocultural background of the patient would aid in the distinguishing culturally bound behavior from behavior that reflects actual psychopathology. This review examines the professional literature on racial and ethnic factors as they pertain to the diagnosis and treatment of black patients in the mental health system.

Adolescent↗
PubMed1991

Dynamic stereotactic radiosurgery using a linear accelerator.

We describe a system for stereotactic radiosurgery with a linear accelerator. This technique allows treatment of small (less than 40 mm diameter) intracranial lesions, including vascular malformations, and primary and metastatic tumors that are deep within the brain or in areas not amenable to open surgery. A beam of ionizing radiation (1800 to 2500 cGy) is focused on the center of the lesion, which is determined by stereotactic localization. "Dynamic rotation" of the linac gantry and table continuously about this predetermined point ensures that only the lesion receives the full radiation dose, while the normal structures in the head receive minimal amounts of radiation. The system combines, for the first time in one place, elements of radiosurgical technique developed at various centers. Testing for accuracy compares favorably with results at other centers using linac-based systems as well as comparing favorably with the gamma knife.

Brain Neoplasms↗
PubMed1990

The nature and extent of hospital competition in a government-funded health system.

A national study of Canadian hospitals assessed the perceived level and types of competition and the strategies pursued by these hospitals. Questionnaire data were obtained from chief executive officers in 715 hospitals, yielding a national response rate of 68%. Respondents indicated the perceived level of competition in the environment, the content of competition, and stated hospital strategies. Additional data were obtained on market share and hospital type. Close to half of the respondents indicated little or no competition in their environment, while 30% indicated substantial levels of competition. This represents a significant deviation from conventional wisdom about the Canadian health services environment. Respondents in hospitals with more than 75% of the market share were less likely to perceive competition than those with a smaller market share. CEOs in teaching hospitals and in hospitals located in larger communities reported higher levels of competition. Hospitals competed mostly for capital, programs, and staff; about a third of hospitals competed for patients and no differences were found by type of institution. Those hospitals in more competitive environments were more likely to indicate the use of diversification and horizontal integration as organizational strategies.

Canada↗
PubMed1989

Economic evaluations in the Canadian Mental Health System. I: Theory behind economic evaluation.

Economic evaluation is becoming an increasingly important part of the evaluation of health and mental health services. Current models for conducting economic evaluation, including cost-effectiveness analysis, cost-benefit analysis, and cost-utility analysis, have great potential for improving the quality of decision-making and for making mental health programs more effective and efficient. This paper presents the basic economic theory underlying the various forms of economic evaluation and provides general guidelines for developing and conducting an economic analysis of a health program.

Canada↗
PubMed1989

Economic evaluations in the Canadian Mental Health System. II: From theory to practice in mental health care.

This paper follows from a previous paper which described the basic approaches to economic evaluation of health programs. The discussion in this paper builds and discusses the theoretical and practical concerns felt by practitioners and analysts about economic evaluations in mental health care. Two examples of economic evaluations that compare the costs of hospital care and community-based care are presented to illustrate some of the limitations of economic evaluation. Discussion also focuses on the difficulties involved in developing and conducting economic analyses in the mental health field, as well as problems faced in trying to generalize from one study setting to others.

Canada↗
PubMed1987

Stereotaxic biopsy and positron emission tomography correlation of cerebral gliomas.

Computer-directed stereotaxis was used to obtain tissue diagnosis in two cases of cerebral glioma, one low grade, and the other high grade. Both lesions had a similar computed tomographic appearance. Positron emission tomography was performed in each case using [18F]fluorodeoxyglucose. A correlation was made in each case between the metabolic activity of the tumor as measured by positron emission tomography, the radiographic appearance, and the tumor histology.

Adult↗
PubMed1986

Superselective intracerebral chemotherapy of malignant tumours with BCNU. Neuroradiological considerations.

Early experience shows that: Superselective intra-arterial catheterization above the ophthalmic artery minimizes the orbital complications. Catheterization in a distal branch may lead to the non-infusion of a part of the tumor territory. A much higher concentration of the drug is achieved by superselective intra-arterial infusion than by intravenous injection. Longer infusions seem more efficacious than bolus injection. Early trapping of the drug appears to be essential for therapeutic efficacy.

Blood-Brain Barrier↗
PubMed1986

Pharmacokinetics of superselective intra-arterial and intravenous [11C]BCNU evaluated by PET.

The pharmacokinetics of i.v. and superselective intra-arterial carbon-11 1,3-bis-(2-chloroethyl)-1-nitrosourea ([11C]BCNU) were directly compared for the first time in ten patients with recurrent gliomas using positron emission tomography (PET). Intra-arterial administration of [11C]BCNU achieved concentrations of the drug in the tumor that averaged 50 times higher than with a comparable i.v. dose. These preliminary results suggest that the degree of early metabolic trapping of BCNU in tumor correlates with the clinical response to this chemotherapy.

Adult↗