Monovalent antibody design and mechanism of action of onartuzumab, a MET antagonist with anti-tumor activity as a therapeutic agent.

Binding of hepatocyte growth factor (HGF) to the receptor tyrosine kinase MET is implicated in the malignant process of multiple cancers, making disruption of this interaction a promising therapeutic strategy. However, targeting MET with bivalent antibodies can mimic HGF agonism via receptor dimerization. To address this limitation, we have developed onartuzumab, an Escherichia coli-derived, humanized, and affinity-matured monovalent monoclonal antibody against MET, generated using the knob-into-hole technology that enables the antibody to engage the receptor in a one-to-one fashion. Onartuzumab potently inhibits HGF binding and receptor phosphorylation and signaling and has antibody-like pharmacokinetics and antitumor activity. Biochemical data and a crystal structure of a ternary complex of onartuzumab antigen-binding fragment bound to a MET extracellular domain fragment, consisting of the MET Sema domain fused to the adjacent Plexins, Semaphorins, Integrins domain (MET Sema-PSI), and the HGF ß-chain demonstrate that onartuzumab acts specifically by blocking HGF α-chain (but not ß-chain) binding to MET. These data suggest a likely binding site of the HGF α-chain on MET, which when dimerized leads to MET signaling. Onartuzumab, therefore, represents the founding member of a class of therapeutic monovalent antibodies that overcomes limitations of antibody bivalency for targets impacted by antibody crosslinking.

The Influences of Health Beliefs and Identity on Adolescent Marijuana and Tobacco Co-Use.

Among youth, the co-use of marijuana and tobacco is highly prevalent, yet a considerable gap remains in the drug-prevention literature pertaining to such co-use. In particular, the prevention field lacks research exploring how adolescents understand the health implications of smoking these two substances in combination. In this article, we draw on qualitative interviews with adolescents from three communities in British Columbia, Canada, and describe the health beliefs and social identities that they associated with smoking marijuana and tobacco. We argue that smoking prevention and cessation initiatives targeting adolescents must address both marijuana and tobacco. Such initiatives must also be designed to identify and address how adolescents frame the potential health harms associated with smoking these substances.

Weeding out the information: an ethnographic approach to exploring how young people make sense of the evidence on cannabis.

BACKGROUND: Contradictory evidence on cannabis adds to the climate of confusion regarding the health harms related to use. This is particularly true for young people as they encounter and make sense of opposing information on cannabis. Knowledge translation (KT) is in part focused on ensuring that knowledge users have access to and understand best evidence; yet, little attention has focused on the processes youth use to weigh scientific evidence. There is growing interest in how KT efforts can involve knowledge users in shaping the delivery of youth-focused public health messages. To date, the youth voice has been largely absent from the creation of public health messages on cannabis. METHODS: This ethnographic study describes a knowledge translation project that focused on engaging young people in a review of evidence on cannabis that concluded with the creation of public health messages generated by youth participants. We facilitated two groups with a total of 18 youth participants. Data included transcribed segments of weekly sessions, researcher field notes, participant research logs, and transcribed follow-up interviews. Qualitative, thematic analysis was conducted. RESULTS: Group dynamics were influential in terms of how participants made sense of the evidence. The processes by which participants came to understand the current evidence on cannabis are described, followed by the manner in which they engaged with the literature for the purpose of creating an individual public health message to share with the group. At project end, youth created collaborative public health messages based on their understanding of the evidence illustrating their capacity to "weed out" the information. The content of these messages reflect a youth-informed harm reduction approach to cannabis use. CONCLUSIONS: This study demonstrates the feasibility of involving young people in knowledge translation initiatives that target peers. Youth participants demonstrated that they were capable of reading scientific literature and had the capacity to engage in the creation of evidence-informed public health messages on cannabis that resonate with young people. Rather than simply being the target of KT messages, they embraced the opportunity to engage in dialogue focused on cannabis.

Development of a two-part strategy to identify a therapeutic human bispecific antibody that inhibits IgE receptor signaling.

The development of bispecific antibodies as therapeutic agents for human diseases has great clinical potential, but broad application has been hindered by the difficulty of identifying bispecific antibody formats that exhibit favorable pharmacokinetic properties and ease of large-scale manufacturing. Previously, the development of an antibody technology utilizing heavy chain knobs-into-holes mutations and a single common light chain enabled the small-scale generation of human full-length bispecific antibodies. Here we have extended the technology by developing a two-part bispecific antibody discovery strategy that facilitates proof-of-concept studies and clinical candidate antibody generation. Our scheme consists of the efficient small-scale generation of bispecific antibodies lacking a common light chain and the hinge disulfides for proof-of-concept studies coupled with the identification of a common light chain bispecific antibody for large-scale production with high purity and yield. We have applied this technology to generate a bispecific antibody suitable for development as a human therapeutic. This antibody directly inhibits the activation of the high affinity IgE receptor FcepsilonRI on mast cells and basophils by cross-linking FcepsilonRI with the inhibitory receptor FcgammaRIIb, an approach that has strong therapeutic potential for asthma and other allergic diseases. Our approach for producing human bispecific full-length antibodies enables the clinical application of bispecific antibodies to a validated therapeutic pathway in asthma.

Opportunities to learn and barriers to change: crack cocaine use in the Downtown Eastside of Vancouver.

In 2004, a team comprised of researchers and service providers launched the Safer Crack Use, Outreach, Research and Education (SCORE) project in the Downtown Eastside of Vancouver, British Columbia, Canada. The project was aimed at developing a better understanding of the harms associated with crack cocaine smoking and determining the feasibility of introducing specific harm reduction strategies. Specifically, in partnership with the community, we constructed and distributed kits that contained harm reduction materials. We were particularly interested in understanding what people thought of these kits and how the kits contents were used. To obtain this information, we conducted 27 interviews with women and men who used crack cocaine and received safer crack kits. Four broad themes were generated from the data: 1) the context of crack use practices; 2) learning/transmission of harm reduction education; 3) changing practice; 4) barriers to change. This project suggests that harm reduction education is most successful when it is informed by current practices with crack use. In addition it is most effectively delivered through informal interactions with people who use crack and includes repeated demonstrations of harm reduction equipment by peers and outreach workers. This paper also suggests that barriers to harm reduction are systemic: lack of safe housing and private space shape crack use practices.

The construction of hepatitis C as a chronic illness.

The purpose of the article is to present one aspect of the findings of a descriptive, exploratory investigation of the self-care decision making of 33 adults diagnosed with chronic hepatitis C (Hep C), specifically how they experienced living with this disease as a chronic illness. The findings were interpreted from a social constructivist perspective in which Hep C was viewed as both a biomedical entity and a social construction. The authors will suggest that although Hep C is constructed by people with the disease as a chronic illness, the care of this disease is often based on an acute model that acknowledges its chronicity only in terms of the persistence of the virus. The article points to the need for a model of Hep C care that incorporates the dimensions of the chronic illness experience.

Sun protection as a family health project in families with adolescents.

This study examined sun protection in families with adolescents from an action-theoretical perspective. Interview data were collected from 20 families about their attitudes and behaviors around sunbathing and sun protection. The data support the understanding of project as joint goal-directed action over time as the basis on which these behaviors are organized in families. Families used the language of goal-directed action to discuss family sun protection. Differences between families with focused and diffuse sun-protection projects are identified. Sun protection in families as one part of an array of family goal-directed actions and projects has implications for health promotion.

Fibroblast growth factor 19 increases metabolic rate and reverses dietary and leptin-deficient diabetes.

Hormonal control of metabolic rate can be important in regulating the imbalance between energy intake and expenditure that underlies the development of obesity. In mice fed a high-fat diet, human fibroblast growth factor 19 (FGF19) increased metabolic rate [1.53 +/- 0.06 liters O(2)/h.kg(0.75) (vehicle) vs. 1.93 +/- 0.05 liters O(2)/h.kg(0.75) (FGF19); P < 0.001] and decreased respiratory quotient [0.82 +/- 0.01 (vehicle) vs. 0.80 +/- 0.01 (FGF19); P < 0.05]. In contrast to the vehicle-treated mice that gained weight (0.14 +/- 0.05 g/mouse.d), FGF19-treated mice lost weight (-0.13 +/- 0.03 g/mouse.d; P < 0.001) without a significant change in food intake. Furthermore, in addition to a reduction in weight gain, treatment with FGF19 prevented or reversed the diabetes that develops in mice made obese by genetic ablation of brown adipose tissue or genetic absence of leptin. To explore the mechanisms underlying the FGF19-mediated increase in metabolic rate, we profiled the FGF19-induced gene expression changes in the liver and brown fat. In brown adipose tissue, chronic exposure to FGF19 led to a gene expression profile that is consistent with activation of this tissue. We also found that FGF19 acutely increased liver expression of the leptin receptor (1.8-fold; P < 0.05) and decreased the expression of acetyl coenzyme A carboxylase 2 (0.6-fold; P < 0.05). The gene expression changes were consistent with the experimentally determined increase in fat oxidation and decrease in liver triglycerides. Thus, FGF19 is able to increase metabolic rate concurrently with an increase in fatty acid oxidation.

Tobacco dependence: adolescents' perspectives on the need to smoke.

To address the need for a better understanding of the perspective of Canadian youths on tobacco dependence, a qualitative study using ethnographic techniques was conducted to describe the patterns of language that they use to describe tobacco dependence and the meaning that it has for them. The study was comprised of three inter-related phases: (1) A secondary analysis of 47 individual unstructured interviews with adolescents was completed to identify the words and phrases they use to explain tobacco dependence; (2) contrast and structural questions focusing on tobacco dependence were developed and used in open-ended interviews with 13 adolescents. Data analysis of the transcribed interviews resulted in a set of 60 key phrases that represented the primary ways youths describe the need to smoke; and (3) interviews were conducted with 14 adolescents that involved an open card sort using the set of 60 key phrases. All card sorts and transcribed interview data were analyzed to identify domains representing types of tobacco dependence and sub-types within each domain. From their descriptions about the need to smoke, five aspects of tobacco dependence were identified: social, pleasurable, empowering, emotional, and full-fledged. This study provides a step in elucidating the construct of tobacco dependence among the young. Further research is required to extend this understanding and to develop appropriate measures.

Synchronizing clinician engagement and client motivation in telephone counseling.

Health care increasingly incorporates telephone counseling, but the interactions supporting its delivery are not well understood. The authors' clinical trial of a tailored, nurse-administered smoking cessation intervention for surgical patients included a telephone counseling component and provided an opportunity to describe the interaction dynamics of proactive telephone counseling over the course of 4 months. Tape-recorded telephone counseling calls for 56 consecutively enrolled individuals randomized to the intervention group resulted in a data set of 368 calls, which were transcribed and analyzed using constant comparative methods. The findings revealed varying interaction dynamics depending on the nurse's level of engagement with participants and participants' motivation to stop smoking. The authors identified four interaction dynamics: affirming/working, chasing/skirting, controlling/withdrawing, and avoiding commitment. Shifts in interaction dynamics were common and influenced the provision of support both positively and negatively. The findings challenge many assumptions underlying telephone counseling and suggest strategies to improve its delivery.

Adolescent constructions of nicotine addiction.

The purpose of this qualitative study was to extend our understanding of how adolescents view nicotine addiction. This secondary analysis included 80 open-ended interviews with adolescents with a variety of smoking histories. The transcribed interviews were systematically analyzed to identify salient explanations of nicotine addiction. These explanations presuppose causal pathways of nicotine exposure leading to addiction and include repeated use, the brain and body "getting used to" nicotine, personal weakness, and family influences. A further explanation is that some youths pretend to be addicted to project a "cool" image. These explanations illustrate that some youths see themselves as passive players in the formation of nicotine addiction. The findings can be used in the development of programs to raise youth awareness about nicotine addiction.

In the shadow of a new smoke free policy: A discourse analysis of health care providers' engagement in tobacco control in community mental health.

BACKGROUND: The prevalence of tobacco use among individuals with mental illness remains a serious public health concern. Tobacco control has received little attention in community mental health despite the fact that many individuals with mental illness are heavy smokers and experience undue tobacco-related health consequences. METHODS: This qualitative study used methods of discourse analysis to examine the perceptions of health care providers, both professionals and paraprofessionals, in relation to their roles in tobacco control in the community mental health system. Tobacco control is best conceptualised as a suite of policies and practices directed at supporting smoke free premises, smoking cessation counselling and limiting access to tobacco products. The study took place following the establishment of a new policy that restricted tobacco smoking inside all mental health facilities and on their grounds. Ninety one health care providers participated in open-ended interviews in which they described their role in tobacco control. The interview data were analyzed discursively by asking questions such as: what assumptions underlie what is being said about tobacco? RESULTS: Five separate yet overlapping discursive frames were identified in which providers described their roles. Managing a smoke free environment emphasised the need to police and monitor the smoke free environment. Tobacco is therapeutic was a discourse that underscored the putative value of smoking for clients. Tobacco use is an individual choice located the decision to smoke with individual clients thereby negating a role in tobacco control for providers. It's someone else's role was a discourse that placed responsibility for tobacco control with others. Finally, the discourse of tobacco control as health promotion located tobacco control in a range of activities that are used to support the health of clients. CONCLUSIONS: This study provides insights into the complex factors that shape tobacco control practices in the mental health field and reinforces the need to see practice change as a matter that extends beyond the individual. The study findings highlight discourses structured by power and powerlessness in environments in which health care providers are both imposing and resisting the smoke free policy.

Relief-oriented use of marijuana by teens.

BACKGROUND: There are indications that marijuana is increasingly used to alleviate symptoms and for the treatment of a variety of medical conditions both physical and psychological. The purpose of this study was to describe the health concerns and problems that prompt some adolescents to use marijuana for therapeutic reasons, and their beliefs about the risks and benefits of the therapeutic use of marijuana. METHODS: As part of a larger ethnographic study of 63 adolescents who were regular marijuana users, we analyzed interviews conducted with 20 youth who self-identified as using marijuana to relieve or manage health problems. RESULTS: Thematic analysis revealed that these teens differentiated themselves from recreational users and positioned their use of marijuana for relief by emphasizing their inability to find other ways to deal with their health problems, the sophisticated ways in which they titrated their intake, and the benefits that they experienced. These teens used marijuana to gain relief from difficult feelings (including depression, anxiety and stress), sleep difficulties, problems with concentration and physical pain. Most were not overly concerned about the risks associated with using marijuana, maintaining that their use of marijuana was not 'in excess' and that their use fit into the realm of 'normal.' CONCLUSION: Marijuana is perceived by some teens to be the only available alternative for teens experiencing difficult health problems when medical treatments have failed or when they lack access to appropriate health care.

Structure-function studies of two synthetic anti-vascular endothelial growth factor Fabs and comparison with the Avastin Fab.

In the quest to discover new research tools and to develop better agents in the fight against cancer, two antibodies, G6 and B20-4, were isolated from synthetic antibody phage libraries. Unlike the AVASTINtrade mark antibody, a recently approved agent for the treatment of patients with colorectal cancer, B20-4 and G6 bind and block both human and murine vascular endothelial growth factor (VEGF). Here we have analyzed and compared the binding epitopes on VEGF for these three antibodies using alanine-scanning mutagenesis and structural analyses. The epitopes recognized by both synthetic antibodies are conserved between human and mouse VEGF, and they match closely to the receptor epitopes both structurally and functionally. In contrast, the Avastin epitope overlaps minimally with the receptor binding surface and centers around a residue that is not conserved in mouse. Our structural and functional analyses elucidate the cross-species reactivity of all three antibodies and emphasize the potential advantages of antibody generation using phage display as the resulting antibodies do not depend on sequence differences across species and preferentially target natural protein-protein interaction surfaces.

Enhanced surveillance of newly acquired hepatitis C virus infection in Canada, 1998 to 2004.

The purpose of this study was to determine trends in disease incidence and recent patterns of hepatitis C virus (HCV) transmission in Canada, using the Enhanced Hepatitis Strain Surveillance System (EHSSS). Demographic, clinical, and potential risk factor information on newly acquired HCV infection, from 1998 to 2004, was collected using standardized questionnaires. During this time period, the reported incidence of newly acquired HCV infection declined by 36.4% from 3.3 cases per 100,000 in 1998, to 2.1 cases per 100,000 in 2004. The disease incidence peaked at 15 to 39 y of age, confirming injecting drug use as the most frequently reported route of transmission. The proportion of cases attributed to health care-acquired HCV infection decreased over this time period. Although the incidence of newly acquired HCV infection in the EHSSS was found to be declining, hepatitis C remains an important public health threat to Canadians. Prevention efforts for HCV should focus on injection drug use, especially for people aged 15 to 39 y.

Exploring the development of sun-tanning behavior: a grounded theory study of adolescents' decision-making experiences with becoming a sun tanner.

A grounded theory study was undertaken to describe how adolescents make decisions about sunbathing during the transition from childhood to adolescence and to propose an explanation for the relationships among factors affecting the adoption of sun tanning. In-depth interviews (n = 40) were conducted separately with adolescents (aged 12 to 16 years) and their parents. Constant comparative analysis of adolescents' accounts identified two methods that adolescents described as a means of getting a suntan: intentional sun tanning and incidental sun tanning. The process of adolescents' decision-making about getting a suntan can be understood by examining the following sequence: becoming motivated to get a tan, experimenting with sun tanning, and establishing self as an intentional tanner or incidental tanner. Implications for developing strategies to prevent the adoption of sun-tanning habits among adolescents are presented.

Efficacy of a smoking-cessation intervention for elective-surgical patients.

We tested an intervention to help smokers abstain (fast) from smoking before surgery, maintain abstinence postoperatively, and achieve long-term cessation. A randomized experiment included 237 patients admitted for presurgical assessment who smoked. The intervention included counseling and nicotine replacement therapy. Treatment group participants (73.0%) were more likely to fast than were controls (53.0%): chi(2)(1, N = 228) = 8.89, p =.003, and more likely to be abstinent 6 months after surgery (31.2% vs. 20.2%). There was no significant difference in the abstinence rates at 12 months after surgery, chi(2)(1, N = 169) <.001, p = 1.00. Encouraging patients to fast from smoking before surgery and postoperative support are efficacious ways to reduce preoperative and immediate post-operative tobacco use.