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BACKGROUND: Surgeons face numerous choices in selecting sutures for skin closure, with potential adverse effects such as tissue tearing. OBJECTIVE: To investigate the influence of needle design and suture gauge on tissue tearing during suturing procedures. MATERIALS AND METHODS: The authors tested the tear-through force in Newtons for 3 needle types and 3 suture gauges using an artificial skin model and a professional-grade tensiometer. Suture material was secured into the skin model, and force was applied to the suture at a constant rate, resulting in tearing. Force-displacement and force-time curves were generated. Evaluation included conventional cutting (PC-3), reverse cutting (PS-3), and taper point (BB) needles with a 5-0 polypropylene suture. In addition, nylon sutures with a reverse cutting needle (PS-2) were tested at 3 suture gauges (5-0, 4-0, 3-0). RESULTS: The mean tear-through forces for PC-3, PS-3, and BB were 3.26 N, 3.75 N, and 4.07 N, respectively. For the 5-0, 4-0, and 3-0 nylon sutures, the mean tear-through forces were 3.44 N, 3.81 N, and 4.04 N, respectively. Statistical analysis revealed a significant impact of suture gauge size (p < .001) and needle geometry (p < .001) on tear-through force. CONCLUSION: Larger suture diameter and taper needles minimize tissue tearing.
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Cortical interneurons shape network activity in cell type-specific ways, and interact with other cell types. These interactions are understudied, as current methods typically restrict in vivo labeling to one neuron type. Although post-hoc identification of many cell types has been accomplished, the method is not available to many labs. We present a method to distinguish two red fluorophores in vivo, allowing imaging of activity in somatostatin (SOM), parvalbumin (PV), and the rest of the neural population in mouse cortex. We compared population events in PV and SOM neurons and observed that local network states reflected the ratio of SOM to PV neuron activity, demonstrating the importance of simultaneous labeling to explain dynamics. Activity became sparser and less correlated when the ratio between SOM and PV activity was high. Our simple method can be flexibly applied to study interactions among any combination of distinct cell type populations across brain areas.
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BACKGROUND: Reverse cutting needles are commonly used in cutaneous surgery due to their perceived ease of use. Despite this, there is limited research evaluating the force required to puncture skin using contemporary needles. OBJECTIVE: This study aims to compare the puncture forces required for two different needle geometries across various gauge sizes. MATERIALS AND METHODS: The authors assessed the force necessary to penetrate samples of human abdominal skin samples using taper needles of three different United States Pharmacopeia gauge sizes with their respective reverse cutting needle counterparts. Taper point needles tested were RB-1 (3-0), TF (4-0), and C-1 (5-0), while reverse cutting needles included PS-2 (3-0) and P-3 (4-0, 5-0). An electronic force meter was used to record the puncture force required by each needle type. RESULTS: The mean puncture force in newtons (N) for taper point needles was 1.00, 0.74, and 0.48 for RB-1, TF, and C-1, respectively. The mean puncture force for reverse cutting needles was 0.95 N, 0.60 N, and 0.51 N for PS-2, P-3 (4-0), and P-3 (5-0), respectively. There was a direct relationship between needle body diameter and puncture force for both needle geometries. CONCLUSION: There was no clinically significant difference in skin puncture force between needle geometries.
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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.
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Eletrocoagulação , Eletrocirurgia , Humanos , Tamanho da Partícula , Material Particulado , Instrumentos CirúrgicosRESUMO
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.
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Neurônios Dopaminérgicos , Objetivos , Animais , Axônios , Neurônios Dopaminérgicos/fisiologia , Humanos , Camundongos , Vias Neurais/fisiologia , Córtex Pré-Frontal/fisiologia , TálamoRESUMO
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.
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Neurônios Dopaminérgicos/fisiologia , Hipotálamo Posterior/citologia , Hipotálamo Posterior/fisiologia , Animais , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Comportamento Consumatório/efeitos dos fármacos , Comportamento Consumatório/fisiologia , Dopamina/fisiologia , Feminino , Ácido Glutâmico/fisiologia , Imageamento por Ressonância Magnética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Modelos Neurológicos , Vias Neurais/citologia , Vias Neurais/fisiologia , Optogenética , Ratos , Ratos Wistar , Reforço Psicológico , Septo do Cérebro/citologia , Septo do Cérebro/efeitos dos fármacos , Septo do Cérebro/fisiologia , Área Tegmentar Ventral/citologia , Área Tegmentar Ventral/fisiologia , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/administração & dosagemRESUMO
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.
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Retalhos Cirúrgicos , Técnicas de Sutura , Humanos , Extremidade Inferior , Transplante de Pele , CicatrizaçãoRESUMO
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.