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Biomedical subjects

H F Clarke

Publications and source records attributed to H F Clarke.

At least 19 recordsLinked to original sources
PubMed2006

Cognitive inflexibility after prefrontal serotonin depletion is behaviorally and neurochemically specific.

We have previously demonstrated that prefrontal serotonin depletion impairs orbitofrontal cortex (OFC)-mediated serial discrimination reversal (SDR) learning but not lateral prefrontal cortex (PFC)-mediated attentional set shifting. To address the neurochemical specificity of this reversal deficit, Experiment 1 compared the effects of selective serotonin and selective dopamine depletions of the OFC on performance of the SDR task. Whereas serotonin depletions markedly impaired performance, OFC dopamine depletions were without effect. The behavioral specificity of this reversal impairment was investigated in Experiment 2 by examining the effect of OFC serotonin depletion on performance of a modified SDR task designed to distinguish between 3 possible causes of the impairment. The results showed that the reversal deficit induced by prefrontal serotonin depletion was not due to a failure to approach a previously unrewarded stimulus (enhanced learned avoidance) or reduced proactive interference. Instead, it was due specifically to a failure to inhibit responding to the previously rewarded stimulus. The neurochemical and behavioral specificity of this particular form of cognitive inflexibility is of particular relevance to our understanding of the aetiology and treatment of inflexible behavior apparent in many neuropsychiatric and neurodegenerative disorders involving the PFC.

5,7-Dihydroxytryptamine↗
PubMed2005

Prefrontal serotonin depletion affects reversal learning but not attentional set shifting.

Recently, we have shown that serotonin (5-HT) depletion from the prefrontal cortex (PFC) of the marmoset monkey impairs performance on a serial discrimination reversal (SDR) task, resulting in perseverative responding to the previously correct stimulus (Clarke et al., 2004). This pattern of impairment is just one example of inflexible responding seen after damage to the PFC, with performance on the SDR task being dependent on the integrity of the orbitofrontal cortex. However, the contribution of 5-HT to other forms of flexible responding, such as attentional set shifting, an ability dependent on lateral PFC (Dias et al., 1996a), is unknown. The present study addresses this issue by examining the effects of 5,7-dihydroxytryptamine-induced PFC 5-HT depletions on the ability to shift attention between two perceptual dimensions of a compound visual stimulus (extradimensional shift). Monkeys with selective PFC 5-HT lesions, despite being impaired in their ability to reverse a stimulus-reward association, were unimpaired in their ability to make an extradimensional shift when compared with sham-operated controls. These findings suggest that 5-HT is critical for flexible responding at the level of changing stimulus-reward contingencies but is not essential for the higher-order shifting of attentional set. Thus, psychological functions dependent on different loci within the PFC are differentially sensitive to serotonergic modulation, a finding of relevance to our understanding of cognitive inflexibility apparent in disorders such as obsessive-compulsive disorder and schizophrenia.

5,7-Dihydroxytryptamine↗
PubMed2004

Cognitive inflexibility after prefrontal serotonin depletion.

Serotonergic dysregulation within the prefrontal cortex (PFC) is implicated in many neuropsychiatric disorders, but the precise role of serotonin within the PFC is poorly understood. Using a serial discrimination reversal paradigm, we showed that upon reversal, selective serotonin depletion of the marmoset PFC produced perseverative responding to the previously rewarded stimulus without any significant effects on either retention of a discrimination learned preoperatively or acquisition of a novel discrimination postoperatively. These results highlight the importance of prefrontal serotonin in behavioral flexibility and are highly relevant to obsessive-compulsive disorder, schizophrenia, and the cognitive sequelae of drug abuse in which perseveration is prominent.

5,7-Dihydroxytryptamine↗
PubMed1998

Comox Valley Nursing Centre: from collaboration to empowerment.

The Comox Valley Nursing Centre was initiated as a two year demonstration project by the Registered Nurses Association of British Columbia (RNABC) and funded by the Ministry of Health. The purpose of the project was to demonstrate innovative nursing practice in a primary health care context. Findings from the project were expected to inform provincial health care planning, nursing scope of practice, and health and nursing policy development. A free standing nursing center was planned and implemented through a collaborative effort by RNABC, nurses and community residents. An external team of researchers evaluated the project using a variety of methods, including participatory action research. During the project an innovative nursing practice, based on principles of collaboration, developed and has continued during the extended provincial and regional funding of the Centre. Drawing from the evaluation findings, case studies and using Henneman, Lee and Cohen's (1995) concept analysis of collaboration, this paper describes how the principles of collaboration were actualized or suppressed. The paper examines how collaboration impacted empowerment for nurses, clients and the community. Lessons learned about the reciprocal relationships between collaboration and empowerment, implications for nursing practice, and how the approach can contribute to a better understanding of the impact of collaborative practice approaches on health care delivery are discussed.

British Columbia↗
PubMed1998

Reducing cervical cancer among First Nations women.

First Nations women in British Columbia have a four to six times higher mortality rate from cancer of the cervix than do women in the general population. Their participation in the provincial Cervical Cytology Screening Program (CCSP) is less regular and less frequent than other women in B.C. Likewise, they have more difficulty in obtaining culturally suitable health care services from respectful and consistent professionals. These issues should be of critical concern to nurses, as nurses provide the majority of health services to First Nations people.

British Columbia↗
PubMed1997

Research in nursing and cultural diversity: working with first nations peoples.

The current Canadian demographic profile indicates a society that is ethnically, culturally, and racially plural (Masi, 1993). Such diversity in our population is likely to increase with broad-based immigration, the implications of which have not been well addressed in nursing and health care. While nurses and other health-care professionals must attend to understanding the cultural aspects of health and healing, there is little published valid and reliable research to assist with this, especially with respect to specific populations. Research approaches and designs must be culturally suitable to the specific populations, to generate valid knowledge about their culture and to develop theory, and to translate that into culturally suitable nursing and health care. In the past, many culturally diverse groups have been the subject of research that has been culturally inappropriate, patronizing, culturally threatening, and disempowering. This paper discusses critical ethnography as a culturally suitable research method and describes its application to studies involving First Nations (FN) peoples. Important issues in doing culturally suitable research, such as partnerships, ethical concerns, and ownership, are also discussed.

Canada↗
PubMed1996

Cervical cytology screening. How can we improve rates among First Nations women in urban British Columbia?

OBJECTIVE: To determine Pap smear screening rates among urban First Nations women in British Columbia; to identify facilitators and barriers; and to develop, implement, and evaluate specific interventions to improve Pap smear screening in Vancouver. DESIGN: Computer records of band membership lists and the Cervical Cytology Screening Program registry were compared to determine screening rates; personal interviews and community meetings identified facilitators and barriers to urban screening programs. A community advisory committee and the project team collaborated on developing specific interventions. SETTING AND PARTICIPANTS: Purposive sample of British Columbia First Nations women, focusing on women living in Vancouver. INTERVENTIONS: Poster, art card, and follow-up pamphlet campaign; articles in First Nations community papers; community meetings; and Pap smear screening clinics for First Nations women. MAIN OUTCOME MEASURES: Pap smear screening rates among BC First Nations women according to residence and reasons for not receiving Pap smears. RESULTS: Pap smear screening rates were substantially lower among First Nations women than among other British Columbia women; older women had even lower rates. No clear differences were found among First Nations women residing on reserves, residing in Vancouver, or residing off reserves elsewhere in British Columbia. Facilitators and barriers to screening were similar among women residing on reserves and in Vancouver. Many First Nations women are greatly affected by health care providers' attitudes, abilities to provide clear information, and abilities to establish trusting relationships. CONCLUSIONS: Family physicians are an important source of information and motivation for Pap smear screening among First Nations women.

Adolescent↗
PubMed1993

Vision for the future of public health nursing: a case for primary health care.

Canada has embraced the goal of the World Health Organization to achieve health for all. This has created a paradigm shift from a focus on direct care to include health promotion and community development, consistent with a primary health care approach. Nevertheless, a clearly articulated vision for the role of public health nurses (PHNs) is lacking. Despite the fact that PHNs make up the largest group of health care workers in the community, their collective opinions and ideas regarding their own practice are seldom sought in a systematic manner. We conducted a survey of public health nurses in British Columbia. Using a two-wave Delphi approach, PHNs were asked to define issues for the future of public health nursing, and to state publicly their preferences for change and transformation. The responses were rank ordered, analyzed, and compared with recent nursing and health care literature to interpret their content. The PHNs' visions for tomorrow agree with concepts of primary health care and community development, and have implications for community health nursing's practice and education.

Attitude of Health Personnel↗
PubMed1993

Public health nurses' vision of their future reflects changing paradigms.

Health care over the past decade has undergone important changes that have implications for public health nursing. The focus of public health has expanded, as a result of the World Health Organization establishing the goal of "Health for All by the Year 2000," with its strategy of primary health care. To be active participants in this expansion, public health nurses must be more explicit about their current contributions to health care systems; develop nursing frameworks consistent with the systems' changing goals; and articulate their visions of the future. It is clear that the medical paradigm of health care services needs to change to one of primary health care. Based on results of a recent public health nursing research study, a conceptual framework for the future practice of public health nursing was developed.

Canada↗
PubMed1992

Barriers to cervical cytology screening in native women in British Columbia.

The British Columbia (BC) Cervical Cytology Screening Programme (CCSP), implemented since 1955, has resulted in a 75% decrease in both the mortality from and incidence of invasive squamous cervical carcinoma. However, despite this effect, the Native Indian population still present an overall mortality rate four times higher than that of the non-Native population. A demonstration project was initiated in four Native Indian Band communities of BC to determine the reasons underlying these findings. The participation patterns to the CCSP were investigated and revealed that the overall percentage of participation to the CCSP among Native Indian women was 30% lower than that of the non-Native population. Reasons for the under-participation to the CCSP were explored. A total of 36 women, 9 in each of the 4 communities, including current users, ex-users and never users, were interviewed. Reasons for not participating in the CCSP were due mainly to (1) the lack of knowledge about the Pap test and about its importance; (2) feelings of embarrassment and shamefulness; (3) lack of continuity of care due to the high turnover of physicians in the Native communities. Based on the study findings, a pilot CCSP clinic will be implemented in each community. In addition to taking cervical smears, this pilot project will include education sessions, notification about the results of the test, and recall for annual check up.

British Columbia↗