Yvan Leduc

Structural and functional analysis of poly(ADP ribose) polymerase: an immunological study

Poly(ADP ribose) polymerase (EC 2.4.2.30) was studied using monoclonal antibodies for three different epitopes on the enzyme. The epitopes were mapped in relation to the functional domains of the protein and the inhibitory properties of the antibodies. The intranuclear and interspecies immunoreactivity of the enzyme was also investigated. The epitope of antibody 2 was mapped to the 17 kDa fragment generated by chymotryptic digestion of the C-terminal 54 kDa NAD-binding domain. Antibody 9 binds to the N-terminal 29 kDa fragment of the DNA binding domain and inhibits the enzyme activity by 80%. This antibody was used to purify poly(ADP ribose) polymerase by immunoaffinity chromatography. The third antibody binds to a central 36 kDa fragment that possesses part of the DNA-binding domain and the automodification domain. This antibody increases the enzymatic activity by 30%. An analysis of the species cross-reactivity of the antibodies was carried out by immunoblot analysis of nuclear proteins. Antibody 10 binding was detected in rat FR3T3 cells, Chinese hamster ovary cells (CHO) and epidermoid carcinoma lung human cells (CALU-1). The other two antibodies are specific for the human and bovine enzymes. Western blot analysis showed the association of poly(ADP ribose) polymerase with residual nuclear material obtained after nuclease treatment and high-salt extraction. Immunofluorescence studies with the three different monoclonals demonstrated that accessibility of the epitopes varies in the nucleus.

Prediction of health professionals' intention to screen for decisional conflict in clinical practice.

Objective  To identify the determinants of the intention of physicians to screen for decisional conflict in clinical practice.

Users' perspectives of key factors to implementing electronic health records in Canada: a Delphi study.

BackgroundInteroperable electronic health record (EHR) solutions are currently being implemented in Canada, as in many other countries. Understanding EHR users’ perspectives is key to the success of EHR implementation projects. This Delphi study aimed to assess in the Canadian context the applicability, the importance, and the priority of pre-identified factors from a previous mixed-methods systematic review of international literature.MethodsA three-round Delphi study was held with representatives of 4 Canadian EHR user groups defined as partners of the implementation process who use or are expected to use EHR in their everyday activity. These groups are: non-physician healthcare professionals, health information professionals, managers, and physicians. Four bilingual online questionnaire versions were developed from factors identified by the systematic review. Participants were asked to rate the applicability and the importance of each factor. The main outcome measures were consensus and priority. Consensus was defined a priori as strong (≥ 75%) or moderate (≥ 60-74%) according to user groups’ level of agreement on applicability and importance, partial (≥ 60%) when participants agreed only on applicability or importance, or as no consensus (< 60%). Priority for decision-making was defined as factors with strong consensus with scores of 4 or 5 on a five-point Likert scale for applicability and importance.ResultsThree Delphi rounds were completed by 64 participants. Levels of consensus of 100%, 64%, 64%, and 44% were attained on factors submitted to non-physician healthcare professionals, health information professionals, managers, and physicians, respectively. While agreement between and within user groups varied, key factors were prioritized if they were classified as strong (≥ 75% from questionnaire answers of user groups), for decision-making concerning EHR implementation. The10 factors that were prioritized are perceived usefulness, productivity, motivation, participation of end-users in the implementation strategy, patient and health professional interaction, lack of time and workload, resources availability, management, outcome expectancy, and interoperability.ConclusionsAmongst all factors influencing EHR implementation identified in a previous systematic review, ten were prioritized through this Delphi study. The varying levels of agreement between and within user groups could mean that users’ perspectives of each factor are complex and that each user group has unique professional priorities and roles in the EHR implementation process. As more EHR implementations in Canada are completed it will be possible to corroborate this preliminary result with a larger population of EHR users.

Patient, primary care physician and specialist expectations of primary care physician involvement in cancer care.

In Canada, many health authorities recommend that primary care physicians (PCP) stay involved throughout their patients’ cancer journey to increase continuity of care. Few studies have focused on patient and physician expectations regarding PCP involvement in cancer care. To compare lung cancer patient, PCP and specialist expectations regarding PCP involvement in coordination of care, emotional support, information transmission and symptom relief at the different phases of cancer. Canadian survey of lung cancer patients, PCPs and cancer specialists A total of 395 patients completed questionnaires on their expectations regarding their PCP participation in several aspects of care, at different phases of their cancer. Also, 45 specialists and 232 community-based PCP involved in these patients’ care responded to a mail survey on the same aspects of cancer care. Most specialists did not expect participation of the PCP in coordination of care in the diagnosis and treatment phases (65% and 78% respectively), in contrast with patients (83% and 85%) and PCPs (80% and 59%) (p < 0.0001). At these same phases, the best agreement among the 3 groups was around PCP role in emotional support: 84% and more of all groups had this expectation. PCP participation in symptom relief was another shared expectation, but more unanimously at the treatment phase (p = 0.85). In the advanced phase, most specialists expect a major role of PCP in all aspects of care (from 81% to 97%). Patients and PCP agree with them mainly for emotional support and information transmission. Lung cancer patient, PCP and specialist expectations regarding PCP role differ with the phase of cancer and the specific aspect of cancer care. There is a need to reach a better agreement among them and to better define PCP role, in order to achieve more collaborative and integrated cancer care.BackgroundIn Canada, many health authorities recommend that primary care physicians (PCP) stay involved throughout their patients’ cancer journey to increase continuity of care. Few studies have focused on patient and physician expectations regarding PCP involvement in cancer care.ObjectiveTo compare lung cancer patient, PCP and specialist expectations regarding PCP involvement in coordination of care, emotional support, information transmission and symptom relief at the different phases of cancer.DesignCanadian survey of lung cancer patients, PCPs and cancer specialistsParticipantsA total of 395 patients completed questionnaires on their expectations regarding their PCP participation in several aspects of care, at different phases of their cancer. Also, 45 specialists and 232 community-based PCP involved in these patients’ care responded to a mail survey on the same aspects of cancer care.ResultsMost specialists did not expect participation of the PCP in coordination of care in the diagnosis and treatment phases (65% and 78% respectively), in contrast with patients (83% and 85%) and PCPs (80% and 59%) (p < 0.0001). At these same phases, the best agreement among the 3 groups was around PCP role in emotional support: 84% and more of all groups had this expectation. PCP participation in symptom relief was another shared expectation, but more unanimously at the treatment phase (p = 0.85). In the advanced phase, most specialists expect a major role of PCP in all aspects of care (from 81% to 97%). Patients and PCP agree with them mainly for emotional support and information transmission.ConclusionLung cancer patient, PCP and specialist expectations regarding PCP role differ with the phase of cancer and the specific aspect of cancer care. There is a need to reach a better agreement among them and to better define PCP role, in order to achieve more collaborative and integrated cancer care.

Family Physician Involvement in Cancer Care Follow-up: The Experience of a Cohort of Patients With Lung Cancer

PURPOSE There has been little research describing the involvement of family physicians in the follow-up of patients with cancer, especially during the primary treatment phase. We undertook a prospective longitudinal study of patients with lung cancer to assess their family physician’s involvement in their follow-up at the different phases of cancer. METHODS In 5 hospitals in the province of Quebec, Canada, patients with a recent diagnosis of lung cancer were surveyed every 3 to 6 months, whether they had metastasis or not, for a maximum of 18 months, to assess aspects of their family physician’s involvement in cancer care. RESULTS Of the 395 participating patients, 92% had a regular family physician but only 60% had been referred to a specialist by him/her or a colleague for the diagnosis of their lung cancer. A majority of patients identified the oncology team or oncologists as mainly responsible for their cancer care throughout their cancer journey, except at the advanced phase, where a majority attributed this role to their family physician. At baseline, only 16% of patients perceived a shared care pattern between their family physician and oncologists, but this proportion increased with cancer progression. Most patients would have liked their family physician to be more involved in all aspects of cancer care. CONCLUSIONS Although patients perceive that the oncology team is the main party responsible for the follow-up of their lung cancer, they also wish their family physicians to be involved. Better communication and collaboration between family physicians and the oncology team are needed to facilitate shared care in cancer follow-up.

Immunoelectron microscopical distribution of poly(ADP-ribose)polymerase in the mammalian cell nucleus.

The ultrastructural distribution of poly(ADP-ribose)polymerase has been studied using a specific antibody and immunocytochemistry with immunogold markers. In situ localization in synchronized Chinese hamster ovary cells reveals the antibody associated with mitotic chromosomes, and later with condensed chromatin and perichromatin regions in G1 phase. During S and G2, the label occurs mostly on perichromatin regions where perichromatin fibrils are also observed. In the nucleolus, the label appears especially on the dense fibrillar component and to a minor extent on the granular component. Immunolabeled spread active chromatin preparations from exponentially growing cultured mouse P815 cells indicate preferential association of the antibody with nascent nonribosomal RNP fibrils compared to inactive chromatin. The results, suggesting a relationship between the poly(ADP-ribose)polymerase occurrence and RNA (or RNP) formation, are discussed in view of the present knowledge about possible relations between poly(ADP-ribosylation) and synthesis of RNA and DNA.

Multi-level analysis of electronic health record adoption by health care professionals: a study protocol.

BackgroundThe electronic health record (EHR) is an important application of information and communication technologies to the healthcare sector. EHR implementation is expected to produce benefits for patients, professionals, organisations, and the population as a whole. These benefits cannot be achieved without the adoption of EHR by healthcare professionals. Nevertheless, the influence of individual and organisational factors in determining EHR adoption is still unclear. This study aims to assess the unique contribution of individual and organisational factors on EHR adoption in healthcare settings, as well as possible interrelations between these factors.MethodsA prospective study will be conducted. A stratified random sampling method will be used to select 50 healthcare organisations in the Quebec City Health Region (Canada). At the individual level, a sample of 15 to 30 health professionals will be chosen within each organisation depending on its size. A semi-structured questionnaire will be administered to two key informants in each organisation to collect organisational data. A composite adoption score of EHR adoption will be developed based on a Delphi process and will be used as the outcome variable. Twelve to eighteen months after the first contact, depending on the pace of EHR implementation, key informants and clinicians will be contacted once again to monitor the evolution of EHR adoption. A multilevel regression model will be applied to identify the organisational and individual determinants of EHR adoption in clinical settings. Alternative analytical models would be applied if necessary.ResultsThe study will assess the contribution of organisational and individual factors, as well as their interactions, to the implementation of EHR in clinical settings.ConclusionsThese results will be very relevant for decision makers and managers who are facing the challenge of implementing EHR in the healthcare system. In addition, this research constitutes a major contribution to the field of knowledge transfer and implementation science.

Monoclonal Antibodies Against Poly(ADP-Ribose) Polymerase: Epitope Mapping, Inhibition of Activity and Interspecies Immunoreactivity

Poly(ADP-ribose) polymerase from different species appears to be structurally conserved in eucaryotes with regard to molecular mass, amino acid composition and enzyme activity as detected by gel electrophoresis (1–3). In addition, analysis of the antigenic structure by immunoblotting with polyclonal antibodies (4, 5) provides evidence that some epitopes are common to various animal cells. We have recently developed monoclonal antibodies against the main functional domains of calf thymus poly(ADPribose) polymerase (6). The purified monoclonal antibodies have been used to map three epitopes along the domains described by Kameshita et al. (7), to examine the presence of these epitopes in the enzyme from different species by immunoblot analysis, and to inhibit enzyme activity in vitro.