The significance of non-significance

Mechanistic Research for the Student or Educator (Part I of II)

Many discoveries in the biological sciences have emerged from observational studies, but student researchers also need to learn how to design experiments that distinguish correlation from causation. For example, identifying the physiological mechanism of action of drugs with therapeutic potential requires the establishment of causal links. Only by specifically interfering with the purported mechanisms of action of a drug can the researcher determine how the drug causes its physiological effects. Typically, pharmacological or genetic approaches are employed to modify the expression and/or activity of the biological drug target or downstream pathways, to test if the salutary properties of the drug are thereby abolished. However, experimental techniques have caveats that tend to be underappreciated, particularly for newer methods. Furthermore, statistical effects are no guarantor of their biological importance or translatability across models and species. In this two-part series, the caveats and strengths of mechanistic preclinical research are briefly described, using the intuitive example of pharmaceutical drug testing in experimental models of human diseases. Part I focuses on technical practicalities and common pitfalls of cellular and animal models designed for drug testing, and Part II describes in simple terms how to leverage a full-factorial ANOVA, to test for causality in the link between drug-induced activation (or inhibition) of a biological target and therapeutic outcomes. Upon completion of this series, students will have forehand knowledge of technical and theoretical caveats in mechanistic research, and comprehend that “a model is just a model.” These insights can help the new student appreciate the strengths and limitations of scientific research.

Downstream Processing Technologies/Capturing and Final Purification : Opportunities for Innovation, Change, and Improvement. A Review of Downstream Processing Developments in Protein Purification

Increased pressure on upstream processes to maximize productivity has been crowned with great success, although at the cost of shifting the bottleneck to purification. As drivers were economical, focus is on now on debottlenecking downstream processes as the main drivers of high manufacturing cost. Devising a holistically efficient and economical process remains a key challenge. Traditional and emerging protein purification strategies with particular emphasis on methodologies implemented for the production of recombinant proteins of biopharmaceutical importance are reviewed. The breadth of innovation is addressed, as well as the challenges the industry faces today, with an eye to remaining impartial, fair, and balanced. In addition, the scope encompasses both chromatographic and non-chromatographic separations directed at the purification of proteins, with a strong emphasis on antibodies. Complete solutions such as integrated USP/DSP strategies (i.e., continuous processing) are discussed as well as gains in data quantity and quality arising from automation and high-throughput screening (HTS). Best practices and advantages through design of experiments (DOE) to access a complex design space such as multi-modal chromatography are reviewed with an outlook on potential future trends. A discussion of single-use technology, its impact and opportunities for further growth, and the exciting developments in modeling and simulation of DSP rounds out the overview. Lastly, emerging trends such as 3D printing and nanotechnology are covered. Graphical Abstract Workflow of high-throughput screening, design of experiments, and high-throughput analytics to understand design space and design space boundaries quickly. (Reproduced with permission from Gregory Barker, Process Development, Bristol-Myers Squibb).

Very low doses of Δ8-THC increase food consumption and alter neurotransmitter levels following weight loss

We have investigated the effect of 0.001 mg/kg delta(8)-tetrahydrocannabinol (THC) on food consumption, cognitive function, and neurotransmitters in mice. Sabra mice were treated with vehicle, THC, or THC+CB1 antagonist (SR141716A). The mice were fed for 2.5 h a day for 9 or 50 days. In the 9-day schedule, THC-treated mice showed a 16% increase in food intake compared with controls (P<.001). This effect was reversed by the antagonist (P<.01). In the long-term schedule a 22% increase in intake (P<.05) was recorded. During the course of the 9- and 50-day experimental protocol, all mice lost about 20% and 10% of their original weight, respectively, to reach approximately the same weights, which were not significantly different between the different treatment groups. In addition, THC caused an increase in activity (P<.05). Cognitive function showed a tendency to improve (P<.06) in the THC-treated mice, which was reversed by the antagonist for Days 4 and 5 of the maze (P<.01, and P<.05, respectively). Significant decreases in dopamine and serotonin (5-HT) levels were found both in the hypothalamus (P<.01) and the hippocampus (P<.01, P<.05), respectively, while norepinephrine (NE) levels showed tendency to increase in both the hypothalamus and hippocampus. Delta(8)-THC increased food intake significantly more (P<.05) than did delta(9)-THC, while performance and activity were similar. Thus, delta(8)-THC (0.001 mg/kg) caused increased food consumption and tendency to improve cognitive function, without cannabimimetic side effects. Hence, a low dose of THC might be a potential therapeutic agent in the treatment of weight disorders.