Andreas G. Franke

Epitope characterization and crystal structure of GA101 provide insights into the molecular basis for type I/II distinction of CD20 antibodies

CD20 is a cell-surface marker of normal and malignant B cells. Rituximab, a monoclonal antibody targeting CD20, has improved the treatment of malignant lymphomas. Therapeutic CD20 antibodies are classified as either type I or II based on different mechanisms of killing malignant B cells. To reveal the molecular basis of this distinction, we fine-mapped the epitopes recognized by both types. We also determined the first X-ray structure of a type II antibody by crystallizing the obinutuzumab (GA101) Fab fragment alone and in complex with a CD20 cyclopeptide. Despite recognizing an overlapping epitope, GA101 binds CD20 in a completely different orientation than type I antibodies. Moreover, the elbow angle of GA101 is almost 30° wider than in type I antibodies, potentially resulting in different spatial arrangements of 2 CD20 molecules bound to a single GA101 or rituximab molecule. Using protein tomography, different CD20 complexes were found to be associated with the 2 antibodies, and confocal microscopy showed different membrane compartmentalization of these subpopulations of the cellular CD20 pool. Our findings offer a possible molecular explanation for the different cellular responses elicited by type I and II antibodies.

Randomized Response Estimates for the 12‐Month Prevalence of Cognitive‐Enhancing Drug Use in University Students

To estimate the 12‐month prevalence of cognitive‐enhancing drug use.

Use of illicit and prescription drugs for cognitive or mood enhancement among surgeons.

BackgroundSurgeons are usually exposed to high workloads leading to fatigue and stress. This not only increases the likelihood of mistakes during surgery but also puts pressure on surgeons to use drugs to counteract fatigue, distress, concentration deficits, burnout or symptoms of depression. The prevalence of surgeons taking pharmacological cognitive enhancement (CE) or mood enhancement (ME) drugs has not been systematically assessed so far.MethodsSurgeons who attended five international conferences in 2011 were surveyed with an anonymous self-report questionnaire (AQ) regarding the use of prescription or illicit drugs for CE and ME and factors associated with their use. The Randomized Response Technique (RRT) was used in addition. The RRT guarantees a high degree of anonymity and confidentiality when a person is asked about stigmatizing issues, such as drug abuse.ResultsA total of 3,306 questionnaires were distributed and 1,145 entered statistical analysis (response rate: 36.4%). According to the AQ, 8.9% of all surveyed surgeons confessed to having used a prescription or illicit drug exclusively for CE at least once during lifetime. As one would expect, the prevalence rate assessed by RRT was approximately 2.5-fold higher than that of the AQ (19.9%; 95% confidence interval (CI), 15.9% to 23.9%, N = 1,105). An even larger discrepancy between the RRT and AQ was observed for the use of antidepressants with a 6-fold higher prevalence (15.1%; 95% CI, 11.3% to 19.0%, N = 1,099) as compared to 2.4% with the AQ. Finally, logistic regression analysis revealed that pressure to perform at work (odds ratio (OR): 1.290; 95% CI, 1.000 to 1.666; P = 0.05) or in private life (OR: 1.266; 95% CI, 1.038 to 1.543; P = 0.02), and gross income (OR: 1.337; 95% CI, 1.091 to 1.640; P = 0.005), were positively associated with the use of drugs for CE or ME.ConclusionsThe use of illicit and prescription drugs for CE or ME is an underestimated phenomenon among surgeons which is generally attributable to high workload, perceived workload, and private stress. Such intake of drugs is associated with attempts to counteract fatigue and loss of concentration. However, drug use for CE may lead to addiction and to overestimation of one’s own capabilities, which can put patients at risk. Coping strategies should be taught during medical education.

Life context of pharmacological academic performance enhancement among university students - a qualitative approach

BackgroundAcademic performance enhancement or cognitive enhancement (CE) via stimulant drug use has received increasing attention. The question remains, however, whether CE solely represents the use of drugs for achieving better academic or workplace results or whether CE also serves various other purposes. The aim of this study was to put the phenomenon of pharmacological academic performance enhancement via prescription and illicit (psycho-) stimulant use (Amphetamines, Methylphenidate) among university students into a broader context. Specifically, we wanted to further understand students’ experiences, the effects of use on students and other factors, such as pressure to perform in their academic and private lives.MethodsA sample of 18 healthy university students reporting the non-medical use of prescription and illicit stimulants for academic performance enhancement was interviewed in a face-to-face setting. The leading questions were related to the situations and context in which the students considered the non-medical use of stimulants.ResultsBased on the resultant transcript, two independent raters identified six categories relating to the life context of stimulant use for academic performance enhancement: Context of stimulant use beyond academic performance enhancement, Subjective experience of enhancement, Timing of consumption, Objective academic results, Side effects, Pressure to perform.ConclusionsThe answers reveal that academic performance enhancement through the use of stimulants is not an isolated phenomenon that solely aims at enhancing cognition to achieve better academic results but that the multifaceted life context in which it is embedded is of crucial relevance. The participants not only considered the stimulants advantageous for enhancing academic performance, but also for leading an active life with a suitable balance between studying and time off. The most common reasons given for stimulant use were to maximize time, to increase motivation and to cope with memorizing. According to the interviews, there is a considerable discrepancy between subjective experiences and objective academic results achieved.

Attitudes Toward Cognitive Enhancement in Users and Nonusers of Stimulants for Cognitive Enhancement: A Pilot Study

Background: The goal of this pilot study was to assess attitudes toward cognitive enhancement (CE) in users and nonusers of prescription or illicit stimulants for CE. Methods: Self-rating questionnaires were used to assess general attitudes toward CE in a sample of 1,035 high school students and 512 undergraduate university students in Germany. Attitudes were also assessed in a subgroup of 49 users of prescription and/or illicit stimulants and compared to the remaining group of nonusers. Results: When asked about the conditions under which participants would consider the use of substances for CE, more than 80% of participants answered that such substances must not lead to long-term damage or addiction if they were to consider using them, while 95% (more often females than males) thought that currently available substances would lead to addiction. Only 16% would not use cognitive enhancers under any condition. A minority of participants (more males than females) stated that students with low academic performance (26%), pilots (21.6%), or physicians (18.9%) should be allowed to use cognitive enhancers; 50.4% would support the use among the cognitively impaired elderly. Compared to nonusers, users were significantly more likely to (1) believe that it was fair for others to use cognitive enhancers, (2) allow the use in students with lower academic performance, and (3) use cognitive enhancers if others did. Reported substance use was associated with higher achievement motivation and with a stronger external locus of control. Conclusions: The disposition to use cognitive enhancers among high school and university students in Germany is high, if substances are safe. However, fear of addiction and doubts about fairness lead most participants to abstain from stimulant use for CE.

Associations between physical and cognitive doping--a cross-sectional study in 2.997 triathletes.

Purpose This study assessed, for the first time, prevalence estimates for physical and cognitive doping within a single collective of athletes using the randomized response technique (RRT). Furthermore, associations between the use of legal and freely available substances to improve physical and cognitive performance (enhancement) and illicit or banned substances to improve physical and cognitive performance (doping) were examined. Methods An anonymous questionnaire using the unrelated question RRT was used to survey 2,997 recreational triathletes in three sports events (Frankfurt, Regensburg, and Wiesbaden) in Germany. Prior to the survey, statistical power analyses were performed to determine sample size. Logistic regression was used to predict physical and cognitive enhancement and the bootstrap method was used to evaluate differences between the estimated prevalences of physical and cognitive doping. Results 2,987 questionnaires were returned (99.7%). 12-month prevalences for physical and cognitive doping were 13.0% and 15.1%, respectively. The prevalence estimate for physical doping was significantly higher in athletes who also used physical enhancers, as well as in athletes who took part in the European Championship in Frankfurt compared to those who did not. The prevalence estimate for cognitive doping was significantly higher in athletes who also used physical and cognitive enhancers. Moreover, the use of physical and cognitive enhancers were significantly associated and also the use of physical and cognitive doping. Discussion The use of substances to improve physical and cognitive performance was associated on both levels of legality (enhancement vs. doping) suggesting that athletes do not use substances for a specific goal but may have a general propensity to enhance. This finding is important for understanding why people use such substances. Consequently, more effective prevention programs against substance abuse and doping could be developed.

Antibodies against CD20 or B-Cell Receptor Induce Similar Transcription Patterns in Human Lymphoma Cell Lines

Background CD20 is a cell surface protein exclusively expressed on B cells. It is a clinically validated target for Non-Hodgkins lymphomas (NHL) and autoimmune diseases. The B cell receptor (BCR) plays an important role for development and proliferation of pre-B and B cells. Physical interaction of CD20 with BCR and components of the BCR signaling cascade has been reported but the consequences are not fully understood. Methodology In this study we employed antibodies against CD20 and against the BCR to trigger the respective signaling. These antibodies induced very similar expression patterns of up- and down-regulated genes in NHL cell lines indicating that CD20 may play a role in BCR signaling and vice versa. Two of the genes that were rapidly and transiently induced by both stimuli are CCL3 and CCL4. 4 hours after stimulation the concentration of these chemokines in culture medium reaches a maximum. Spleen tyrosine kinase Syk is a cytoplasmic tyrosine kinase and a key component of BCR signaling. Both siRNA mediated silencing of Syk and inhibition by selective small molecule inhibitors impaired CCL3/CCL4 protein induction after treatment with either anti-CD20 or anti-BCR antibodies. Conclusion Our results suggest that treatment with anti-CD20 antibodies triggers at least partially a BCR activation-like response in NHL cell lines.

Reflections on Addiction in Students Using Stimulants for Neuroenhancement: A Preliminary Interview Study.

The use of stimulants for the purpose of pharmacological neuroenhancement (NE) among students is a subject of increasing public awareness. The risk of addiction development by stimulant use for NE is still unanswered. Therefore, face-to-face interviews were carried out among 18 university students experienced in the nonmedical use of methylphenidate and amphetamines for NE assessing aspects of addiction. Interviews were tape-recorded, verbatim-transcribed, and analyzed using a qualitative approach. The interviews showed that participants—the majority had current or lifetime diagnoses of misuse or addiction to alcohol or cannabis—reported an awareness of the risk of addiction development associated with stimulant use and reported various effects which may increase their likelihood of future stimulant use, for example, euphoric effects, increase of self-confidence, and motivation. They also cited measures to counteract the development of addiction as well as measures taken to normalize again after stimulant use. Students were convinced of having control over their stimulant use and of not becoming addicted to stimulants used for NE. We can conclude that behavior and beliefs of the students in our sample appear to be risky in terms of addiction development. However, long-term empirical research is needed to estimate the true risk of addiction.

The Use of Caffeinated Substances by Surgeons for Cognitive Enhancement.

OBJECTIVE To investigate the use of coffee, caffeinated drinks, and caffeine tablets for pharmacological cognitive enhancement (CE) among surgeons. BACKGROUND Surgeons have demanding workloads, and the resulting fatigue and concentration deficits can lead to medical errors. Some surgeons use substances that promote wakefulness to counteract these effects. METHODS A total of 3306 surgeons who attended 5 international conferences in 2011 were surveyed regarding their use of coffee, caffeinated drinks, and caffeine tablets for CE and potential factors derived from professional and private life using an anonymous self-report questionnaire. In this study, we were only interested in surgeons working in hospitals; therefore, 951 questionnaires were statistically analyzed. RESULTS The most prevalent reason for using caffeine of any kind was to reduce fatigue (54.3%). Further prevalent reasons are working the night shift (32.2%) and overly long and excessive work hours (31.7%). Lifetime, past-year, past-month, and past-week prevalence was 66.8%, 61.9%, 56.9%, and 50.5%, for coffee use; 24.2%, 15.4%, 9.9%, and 6.1%, for caffeinated drinks; and 12.6%, 5.9%, 4.7%, and 3.8%, respectively, for caffeine tablets. Caffeine use was associated with lower age, male sex, divorced marital status, living with children, lack of satisfaction with professional status, pressure to perform in private life, and pressure perceived to be harmful to ones own health. CONCLUSIONS Surgeons often use caffeinated substances to cope with fatigue and long working hours. Coffee use was more prevalent than the use of caffeinated drinks and caffeine tablets.

Pharmacological Neuroenhancement in the Field of Economics-Poll Results from an Online Survey

Introduction: The use of over-the-counter, prescription, and illicit drugs to increase attention, concentration, or memory—often called (pharmacological) neuroenhancement—shows a broad range of prevalence rates among students. However, very little data is available on neuroenhancement among employed persons. The aim of this study was to provide first data on substance use for neuroenhancement among readers of the German “Handelsblatt” coming from the field of economics. Methods: Readers of the online edition of the Handelsblatt, a leading print and online medium for the field of economics, were invited to participate in a survey via a link on the journal homepage to complete a web-based questionnaire. Within the questionnaire, participants were asked for their gender, current age, current professional status, hours of work per week, prevalence rates of substance use for the purpose of neuroenhancement as well as for reasons of its use. Binary regression analyses with stepwise forward selection were used to predict the dependent variables “use of illicit and prescription drugs for neuroenhancement” (yes/no), “use of over-the-counter drugs for neuroenhancement” (yes/no), and “use of any drug for neuroenhancement” (yes/no). Results: A total of 1021 participants completed the anonymous survey. Lifetime prevalence for the use of any drug for neuroenhancement was 88.0% and for the use of illicit and prescription drugs for neuroenhancement 19.0%. Reasons and situations that predicted neuroenhancement with illicit and prescription drugs were “curiosity,” “to enhance mood,” ”for a confident appearance,” “stress/pressure to perform,” and “deadline pressure.” Discussion: The study shows that neuroenhancement with drugs is a widespread and frequent phenomenon among people belonging to the professional field of economics. Given in the literature that the use of drugs, especially prescription, and illicit drugs, may be associated with side effects, the high epidemic of drug use for neuroenhancement also shown in the present paper underlines the new public health concern of neuroenhancement.