Advances in Medicine and Biology. Volume 161 first discusses the relationship between varicocele and sperm DNA methylation status. Varicocele is a major cause of male infertility where increased testicular temperature, oxidative stresses, abnormal chromatin packaging and reduced DNA methylation account for reduced sperm quality. The authors also discuss the use of reproductive biotechniques in the equine species, particularly artificial insemination, which dates back to the end of the 19th century and is widely used around the world today. Following this, the principle mechanisms behind and the potential clinical applications of histotripsy are explored. In histotripsy, there are two different methods of creating pure mechanical damage of soft tissue: ultrasound cavitation or shock wave heating and millisecond boiling. Direct and indirect targets likely associated with Cdc42 activation are highlighted, which demonstrate potential for further investigation in DNA damage-associated events. The authors review the exact mode of action of old and new anti-seizure molecules, as well as the benefits, concerns and latest recommendations for rational and appropriate antiepileptic drug therapy. Later, the abstract thinking regarding the constraint-based notion of systems biology is applied to the scientific field of clinical cardiology. Constraint-based thinking with downward causation is an important holistic concept of systems biology, explaining many aspects of all biological entities. The concluding study is focused on the structure, regulation and functions of PPP ser/thr phosphatases in higher plants. This functional characterization is accompanied by structural and biochemical data.