Plume Generated by Different Electrosurgical Techniques: An In Vitro Experiment on Human Skin.

BACKGROUND: Plume generated by electrosurgical techniques is a health hazard to patients and dermatologists. OBJECTIVE: To compare the particle concentration generated by various energy devices used in dermatologic surgery. MATERIALS AND METHODS: Five surgical techniques were tested on human tissue samples in a closed chamber. A particle counter, positioned at a fixed point 20 cm away from the sample, recorded the concentrations of aerosolized particles generated over 7 particle sizes (0.3, 0.5, 0.7, 1, 2.5, 5, and 10 µm). RESULTS: Monopolar electrocoagulation created the greatest concentration of particles followed by electrocautery, electrodesiccation, electrofulguration, and bipolar electrocoagulation. Bipolar electrocoagulation created 80 times fewer 0.3 µm particles and 98 times fewer 0.5 µm particles than monopolar electrocoagulation. Across all electrosurgical techniques, the greatest concentrations of particles generated were of the 0.3 and 0.5 µm particle size. CONCLUSION: Bipolar electrocoagulation created the lowest concentration of particulate matter. Given the noxious and hazardous nature of surgical plume, the bipolar forceps offer surgeons a safer method of performing electrical surgery for both the surgical staff and the patient.

The Twizzler: a modified primary closure for distal lower extremity wound reconstruction utilizing a dynamic winch stitch.

Management of lower extremity wounds following successful tumor excision presents multiple challenges. Distal lower extremity integument is highly prone to edema often lacks adequate skin laxity for standard primary closures. The closure must be resilient enough to withstand mobility. As a result, optimal reconstruction may include skin grafting, rotational flaps, free tissue transfers, healing by second intention, or some combination. These methods may involve multiple steps in reconstruction, a prolonged recovery period, increased cost, and higher infection risk. We propose a modified primary closure that takes advantage of the visco-elastic properties of the skin without introducing additional components or steps. This technique is initiated with percutaneous suture in order to intermittently stretch the skin with constant tension. This load cycling allows for lower extremity skin to stretch over time and ultimately reduce wound edge tension, allowing for ease of absorbable suture placement. The Twizzler technique is cost-effective, uses readily available supplies, and effectively closes relatively large defects on the lower extremities.

Medial prefrontal cortex and anteromedial thalamus interaction regulates goal-directed behavior and dopaminergic neuron activity.

The prefrontal cortex is involved in goal-directed behavior. Here, we investigate circuits of the PFC regulating motivation, reinforcement, and its relationship to dopamine neuron activity. Stimulation of medial PFC (mPFC) neurons in mice activated many downstream regions, as shown by fMRI. Axonal terminal stimulation of mPFC neurons in downstream regions, including the anteromedial thalamic nucleus (AM), reinforced behavior and activated midbrain dopaminergic neurons. The stimulation of AM neurons projecting to the mPFC also reinforced behavior and activated dopamine neurons, and mPFC and AM showed a positive-feedback loop organization. We also found using fMRI in human participants watching reinforcing video clips that there is reciprocal excitatory functional connectivity, as well as co-activation of the two regions. Our results suggest that this cortico-thalamic loop regulates motivation, reinforcement, and dopaminergic neuron activity.

Supramammillary neurons projecting to the septum regulate dopamine and motivation for environmental interaction in mice.

The supramammillary region (SuM) is a posterior hypothalamic structure, known to regulate hippocampal theta oscillations and arousal. However, recent studies reported that the stimulation of SuM neurons with neuroactive chemicals, including substances of abuse, is reinforcing. We conducted experiments to elucidate how SuM neurons mediate such effects. Using optogenetics, we found that the excitation of SuM glutamatergic (GLU) neurons was reinforcing in mice; this effect was relayed by their projections to septal GLU neurons. SuM neurons were active during exploration and approach behavior and diminished activity during sucrose consumption. Consistently, inhibition of SuM neurons disrupted approach responses, but not sucrose consumption. Such functions are similar to those of mesolimbic dopamine neurons. Indeed, the stimulation of SuM-to-septum GLU neurons and septum-to-ventral tegmental area (VTA) GLU neurons activated mesolimbic dopamine neurons. We propose that the supramammillo-septo-VTA pathway regulates arousal that reinforces and energizes behavioral interaction with the environment.

A comparison of the Avisoft (5.2) and Ultravox (2.0) recording systems: Implications for early-life communication and vocalization research.

Alterations in early-life communicative behaviors are a common feature of neurodevelopmental conditions, such as autism and epilepsy. One method of investigating communication in murine models is through analyzing ultrasonic vocalizations. These vocalizations are commonly recorded with either the Avisoft or the Ultravox recording programs. However, since no study has compared whether the systems are equally sensitive, the findings in one program may not be reproducible in the other. To directly compare the two programs, we elicited vocalizations from male and female 129SvEvTac and C57BL/6 mouse pups via the maternal isolation paradigm, recording vocalizations simultaneously with both systems. We held the detection parameters identical for each system and found that there was only a medium correlation between Avisoft and Ultravox overall. Further analysis indicated that Avisoft detected more total vocalizations, as well as more vocalizations at the set frequencies of 50, 60, and 70 kHz than Ultravox, p < .05. No statistically significant difference was present at 80 kHz. These findings demonstrate that different recording systems do not detect the same quantity of vocalizations as one another, even when detection parameters are congruent. Therefore, it may be useful to revisit previous negative results obtained with Ultravox and repeat the experiments using Avisoft. Ultimately, ultrasonic vocalizations are a valuable tool, capable of examining early-life phenotypes. However, a more thorough understanding of the relationships between recording systems is necessary to achieve a more comprehensive and reproducible assessment of vocalizing behaviors.