N-tert-butoxycarbonyl-methylenedioxymethamphetamine, an methylenedioxymethamphetamine derivative, exhibits rewarding and reinforcing effects by increasing dopamine levels.

An N-protected methylenedioxymethamphetamine (MDMA), N-tert-butoxycarbonyl-3,4-methylenedioxymethamphetamine (t-BOC-3,4-MDMA), contains tert-butoxycarbonyl and can remain undetected in the illicit drug market. It is a new type of precursor substance that is not a chemical intermediate and can be converted into a controlled substance, MDMA, by deprotection of the N-tert-butoxycarbonyl group. Categorization of this chemical into a precursor or psychotropic substance is an issue because it is an unprecedented precursor that could have misuse potential. Although MDMA causes rewarding and reinforcing effect through dopaminergic transmission, the misuse potential of t-BOC-3,4-MDMA has not yet been characterized. Here, we aim to evaluate the misuse potential of t-BOC-3,4-MDMA. The response to the drug at a dose of 5 mg/kg was determined by a climbing test, and its rewarding and reinforcing properties were assessed through conditioned place preference and self-administration tests. In the conditioned place preference test, intraperitoneal administration of t-BOC-3,4-MDMA (5 mg/kg) significantly altered place preference in mice. In the self-administration models, t-BOC-3,4-MDMA induced drug-taking behavior at the dose of 0.5 mg/kg/infusion (intravenous) during 2 hr sessions under fixed-ratio schedules in mice. In addition, microdialysis experiments verified that t-BOC-3,4-MDMA impacted the dopamine levels of the brain (striatum) of rats. These experimental results indicate that t-BOC-3,4-MDMA has a potential for misuse. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Psychological effects of anti-Arab politics on American and Arab peoples' views of each other.

Disparaging rhetoric about Arab people was prevalent during Donald Trump's political rise in the United States. Although this rhetoric was intended to energize conservative Americans, it also echoed throughout many liberal parts of the United States and around the world. In this research, we experimentally examined the effects of such rhetoric on American and Arab people's attitudes and visual representations of each other before and after Trump was elected. Although people overwhelmingly reported not liking the negative rhetoric, the rhetoric alone did not influence explicit and implicit intergroup biases in either location, as measured by feeling thermometers and Implicit Association Tests. However, the election outcome moderated the way rhetoric influenced how American and Arab people visually represented each other. Our research sheds light on nuanced effects of global politics on various information processing stages within intergroup perception.

Plastic Wound Protector vs Surgical Gauze for Surgical Site Infection Reduction in Open GI Surgery: A Randomized Clinical Trial.

Importance: Surgical site infections (SSIs) are prevalent hospital-acquired infections with significant patient impacts and global health care burdens. The World Health Organization recommends using wound protector devices in abdominal surgery as a preventive measure to lower the risk of SSIs despite limited evidence. Objective: To examine the efficacy of a dual-ring, plastic wound protector in lowering the SSI rate in open gastrointestinal (GI) surgery irrespective of intra-abdominal contamination levels. Design, Setting, and Participants: This multicenter, patient-blinded, parallel-arm randomized clinical trial was conducted from August 2017 to October 2022 at 13 hospitals in an academic setting. Patients undergoing open abdominal bowel surgery (eg, for bowel perforation) were eligible for inclusion. Intervention: Patients were randomized 1:1 to a dual-ring, plastic wound protector to protect the incision site of the abdominal wall (experimental group) or a conventional surgical gauze (control group). Main Outcomes and Measures: The primary end point was the rate of SSI within 30 days of open GI surgery. Results: A total of 458 patients were randomized; after 1 was excluded from the control group, 457 were included in the intention-to-treat analysis (mean [SD] age, 58.4 [12.1] years; 256 [56.0%] male; 341 [74.6%] with a clean-contaminated wound): 229 in the wound protector group and 228 in the surgical gauze group. The overall SSI rate in the intention-to-treat analysis was 15.7% (72 of 458 patients). The SSI rate for the wound protector was 10.9% (25 of 229 patients) compared with 20.5% (47 of 229 patients) with surgical gauze. The wound protector significantly reduced the risk of SSI, with a relative risk reduction (RRR) of 46.81% (95% CI, 16.64%-66.06%). The wound protector significantly decreased the SSI rate for clean-contaminated wounds (RRR, 43.75%; 95% CI, 3.75%-67.13%), particularly for superficial SSIs (RRR, 42.50%; 95% CI, 7.16%-64.39%). Length of hospital stay was similar in both groups (mean [SD], 15.2 [10.5] vs 15.3 [10.2] days), as were the overall postoperative complication rates (20.1% vs 18.8%). Conclusions and Relevance: This randomized clinical trial found a significant reduction in SSI rates when a plastic wound protector was used during open GI surgery compared with surgical gaze, supporting the World Health Organization recommendation for use of wound protector devices in abdominal surgery. Trial Registration: ClinicalTrials.gov Identifier: NCT03170843.

Reducing Facial Stereotype Bias in Consequential Social Judgments: Intervention Success With White Male Faces.

Initial impressions of others based on facial appearances are often inaccurate yet can lead to dire outcomes. Across four studies, adult participants underwent a counterstereotype training to reduce their reliance on facial appearance in consequential social judgments of White male faces. In Studies 1 and 2, trustworthiness and sentencing judgments among control participants predicted whether real-world inmates were sentenced to death versus life in prison, but these relationships were diminished among trained participants. In Study 3, a sequential priming paradigm demonstrated that the training was able to abolish the relationship between even automatically and implicitly perceived trustworthiness and the inmates' life-or-death sentences. Study 4 extended these results to realistic decision-making, showing that training reduced the impact of facial trustworthiness on sentencing decisions even in the presence of decision-relevant information. Overall, our findings suggest that a counterstereotype intervention can mitigate the potentially harmful effects of relying on facial appearance in consequential social judgments.

Evaluation of the resection efficiency and safety of an enhanced power plasma generator using cadaveric intervertebral discs.

Plasma energy has been used to provide minimally invasive interventional treatment for spinal problems. However, this procedure has been used for limited indications mainly because of its small resection range. To overcome this problem, we designed the enhanced power plasma device. This device seeks to maximize the resection area by modifying the electrode arrangement and enhancing the maximum electric power. The purpose of this study is to assess the efficiency and safety of this newly designed plasma generator, a device for percutaneous disc decompression. We performed an intradiscal procedure on 7 fresh human cadaver lumbar spine specimens using the enhanced power plasma under C-arm fluoroscopic guidance at various voltages. As a result, the volume of the removed area was proportional to the applied magnitude of the electric power level. In particular, under the high-power level condition after 500 s treatment, nearly the entire nucleus pulposus was eliminated. The generated plasma density also tends to grow along with the given electric power. The highest level of temperature rise did not exceed the level that would lead to degeneration in the collagen tissue of the intervertebral disc. Histopathologic examination also demonstrated that there was no thermal damage to the surrounding neural tissues. In conclusion, we speculate that the concepts of this newly designed enhanced plasma generator could be applied to remove huge disc materials without thermal or structural damage to the adjacent target tissues in future spine clinics.

Rewarding and Reinforcing Effects of 25H-NBOMe in Rodents.

The drug 25H-NBOMe is a new psychoactive substance (NPS). The use of these substances is likely to pose a threat to public health because they elicit effects similar to those of known psychoactive substances with similar chemical structures. However, data regarding the abuse potential of 25H-NBOMe are lacking. Here, we evaluated the abuse liability of 25H-NBOMe in rodents. The rewarding and reinforcing effects were evaluated through conditioned place preference (CPP) and self-administration (SA) tests after administration of 25H-NBOMe. To investigate the effects of 25H-NBOMe on the central nervous system, we determined the changes in dopamine levels by in vivo microdialysis. In the locomotor activity test, 25H-NBOme significantly increased locomotor activity in mice. In the place conditioning test, the 25H-NBOMe (0.1 and 0.5 mg/kg) groups showed a significantly increase in CPP in mice. In the SA test, the 25H-NBOMe (0.01 mg/kg) administered group showed a significant increased number of infusions and active lever presses. In microdialysis, the 25H-NBOMe (10 mg/kg) administered group was significantly increased in rats.

Scrutinizing Whether Mere Group Membership Influences the N170 Response to Faces: Results from Two Preregistered Event-Related Potential Studies.

A socially consequential test of the cognitive penetrability of visual perception is whether merely sharing a group membership with another person influences how you encode their face. Past research has examined this issue by manipulating group membership with techniques from social psychology and then measuring the face-sensitive N170 ERP. However, methodological differences across studies make it difficult to draw conclusions from this literature. In our research, we conducted two large-scale, preregistered ERP studies to address how critical methodological decisions could influence conclusions about top-down effects of group membership on face perception. Specifically, we examined how mere group membership, perceptual markers that signify group membership, number of trials included in the study design, the racial/ethnic identity of face stimuli, and the data analytic approach affect inferences about the N170 response to faces. In Study 1, we found no evidence that mere group membership significantly influenced the N170. However, we found that the background color used to signify group membership modulated the magnitude and latency of the N170. Exploratory analyses also showed effects of stimulus race/ethnicity. In Study 2, we dissociated background color from face encoding by presenting background color before the faces. In this second study, we found no main effect of group membership, background color, or stimulus race/ethnicity. However, we did see an unhypothesized mere group membership effect on trials toward the end of the study. Our results inform debates about social categorization effects on visual perception and show how bottom-up indicators of group membership can bias face encoding.

Potential of Snapshot-Type Hyperspectral Imagery Using Support Vector Classifier for the Classification of Tomatoes Maturity.

It is necessary to convert to automation in a tomato hydroponic greenhouse because of the aging of farmers, the reduction in agricultural workers as a proportion of the population, COVID-19, and so on. In particular, agricultural robots are attractive as one of the ways for automation conversion in a hydroponic greenhouse. However, to develop agricultural robots, crop monitoring techniques will be necessary. In this study, therefore, we aimed to develop a maturity classification model for tomatoes using both support vector classifier (SVC) and snapshot-type hyperspectral imaging (VIS: 460-600 nm (16 bands) and Red-NIR: 600-860 nm (15 bands)). The spectral data, a total of 258 tomatoes harvested in January and February 2022, was obtained from the tomatoes' surfaces. Spectral data that has a relationship with the maturity stages of tomatoes was selected by correlation analysis. In addition, the four different spectral data were prepared, such as VIS data (16 bands), Red-NIR data (15 bands), combination data of VIS and Red-NIR (31 bands), and selected spectral data (6 bands). These data were trained by SVC, respectively, and we evaluated the performance of trained classification models. As a result, the SVC based on VIS data achieved a classification accuracy of 79% and an F1-score of 88% to classify the tomato maturity into six stages (Green, Breaker, Turning, Pink, Light-red, and Red). In addition, the developed model was tested in a hydroponic greenhouse and was able to classify the maturity stages with a classification accuracy of 75% and an F1-score of 86%.

The abuse potential of prolintane in rodents: Behavioral pharmacology approaches.

Prolintane (1-Phenyl-2-pyrrolidinylpentane), a synthetic central nervous system (CNS) stimulant, is structurally similar to amphetamine but pharmacologically acts as a dopamine reuptake inhibitor like cocaine. While several case studies reported adverse effects and recreational use of prolintane, the abuse potential of the drug has not been systemically examined yet. In the present study, we evaluated the behavioral effects of prolintane regarding its abuse liability in rodents using locomotor activity, conditioned place preference (CPP), self-administration (SA), and drug discrimination paradigms, as well as in-vivo microdialysis experiment. First, acute prolintane (10 and 20 mg/kg, intraperitoneal injection) increased locomotor activity (distance traveled, cm) in mice but to a lesser degree than methamphetamine (as a positive control). We also found that a single and solitary injection of prolintane (20 mg/kg, IP) significantly increased extracellular dopamine in the striatum. The following result suggests that its stimulatory effects might be associated with the mesolimbic dopaminergic pathway. Further, prolintane produced a significant drug-paired place preference at doses of both 10 and 20 mg/kg. In the SA experiment, the mice that self-administered prolintane intravenously (4 mg/kg/inf) showed a higher infusion and active lever responses but not inactive lever responses. Additionally, cumulative doses of prolintane partially elicited cocaine-appropriate lever responses (38.57% at doses up to 10 mg/kg) in rats. These results implied that prolintane has not only rewarding and reinforcing effects but also interoceptive stimulus properties, which are similar to cocaine at a moderate level. Taken together, this study was the first to show, to our knowledge, that prolintane has a certain level of abuse potential and should be considered carefully as a valuable basis for legal restrictions on use.

Characterization of in vitro phase I metabolites of methamnetamine in human liver microsomes by liquid chromatography-quadrupole time-of-flight mass spectrometry.

N-Methyl-1-(naphthalen-2-yl)propan-2-amine (methamnetamine, PAL-1046) is an amphetamine-based new psychoactive substance (NPS). Methamnetamine has been reported to cause excessive release of serotonin, and it is classified as an empathogen or entactogen. It is not regulated as a controlled substance in most countries, and there are no studies on its metabolism. In this study, in vitro phase I metabolism of methamnetamine in human liver microsomes (HLM) and flavin-containing monooxygenase (FMO) was investigated by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS). Eight metabolites of methamnetamine were identified and were structurally characterized achieved by a combination of accurate mass analysis and tandem mass spectrometry. The identified metabolic processes include N-demethylation, N-hydroxylation, aromatic hydroxylation, and a combination of these processes. N-Hydroxylated metabolites were confirmed based on expressed FMOs. The major metabolite was formed from methamnetamine via hydroxylation of the naphthalene ring after the in vitro phase I process. These results could help detect methamnetamine ingestion by NPS abusers.

Assessment of the abuse potential of methamnetamine in rodents: a behavioral pharmacology study.

RATIONALE: Methamnetamine (MNA; PAL-1046) is a new psychoactive substance that acts as a full biogenic amine transporter (BAT) substrate. BAT substrates promote neurotransmitter release from the nerve terminal and can be abused as stimulants. However, scientific information on the abuse potential of methamnetamine is lacking. OBJECTIVE: We evaluated the abuse liability of methamnetamine. METHODS: The effective dose range of methamnetamine was determined using a climbing behavior test. The rewarding effect and reinforcing effect of the test compound were evaluated in mice by conditioned place preference (CPP) testing and self-administration (SA) testing at the selected doses. Dopamine level changes were analyzed using synaptosomes and in vivo microdialysis to investigate the effects of methamnetamine on the central nervous system. Drug discrimination experiments were used to examine the potential similarity of the interoceptive effects of methamnetamine and cocaine. RESULTS: A significant response was observed in the climbing behavior test with 10 and 40 mg/kg intraperitoneally administered methamnetamine. In the CPP test, mice intraperitoneally administered methamnetamine (10 and 20 mg/kg) showed a significant preference for the drug-paired compartment. In the SA test, mice that intravenously received 1 mg/kg/infusion showed significant active-lever responses. Dopamine was significantly increased in synaptosomes and in in vivo microdialysis tests. Furthermore, methamnetamine showed cross-generalization with cocaine in a dose-dependent manner. CONCLUSIONS: Methamnetamine exhibits interceptive stimulus properties similar to those of cocaine and induces rewarding and reinforcing effects, suggesting its dependence liability potential.

Can normalized carcinoembryonic antigen following neoadjuvant chemoradiation predict tumour recurrence after curative resection for locally advanced rectal cancer?

AIM: The aim of this work was to evaluate whether normalized carcinoembryonic antigen (CEA) following neoadjuvant chemoradiation predicts the prognosis following curative resection in locally advanced rectal cancer. METHOD: Patients who underwent neoadjuvant chemoradiation and curative resection for locally advanced rectal cancer between 2010 and 2015 were divided into three groups: Group A (n = 119, normal-to-normal): normal CEA before and after neoadjuvant chemoradiation; Group B (n = 37, high-to-normal): elevated CEA before and normal CEA after neoadjuvant chemoradiation; Group C (n = 36, high-to-high): elevated CEA before and after neoadjuvant chemoradiation. Overall and disease-free survival were compared. Univariate and multivariate analyses identified potential predictors for recurrence. RESULTS: One hundred and ninety two patients [median age 59 years (range 31-87), 65.1% male] were identified: 54.7% had low rectal cancer: 12.5% were clinical stage T4 and 70.3% were clinically node positive; 21.9% achieved complete pathological response; 24.5% had abdominoperineal resection (APR); and 70.3% underwent adjuvant chemotherapy following curative resection. Significantly more patients in Group C underwent APR (p = 0.0209), had advanced pathological T stage (P = 0.0065) and a higher prevalence of perineural invasion (p = 0.0042). Overall and disease-free survival were significantly higher for Group A than for Group C [hazard ratio (HR) = 4.32, 95% CI = 1.66-11.21, p = 0.0026 and HR=2.68, 95% CI = 1.33-5.40, p = 0.0057, respectively]. No significant difference was noted between Groups A and B for overall (p = 0.0591) or disease-free (p = 0.2834) survival. Another risk factor associated with recurrence and death was clinical T4 stage; nodal positivity was a risk factor only for recurrence. CONCLUSION: Elevated CEA after neoadjuvant chemoradiation and clinical stage T4 disease were unfavourable predictors for overall and disease-free survival. Normalized CEA during neoadjuvant chemoradiation may serve as a prognosticator, although pretreatment CEA may significantly affect survival.

Minimal but not meaningless: Seemingly arbitrary category labels can imply more than group membership.

Minimal group paradigms tend to involve contrived group distinctions, such as dot estimation tendencies and aesthetic preferences. Researchers assume that these novel category distinctions lack informational value. Our research tests this notion. Specifically, we used the classic overestimator versus underestimator and Klee versus Kandinsky minimal group paradigms to assess how category labels influence minimal group responses. In Study 1, we show that participants represented ingroup faces more favorably than outgroup faces, but also represented overestimator and underestimator category labels differently. In fact, the category label effect was larger than the intergroup effect, even though participants were told that estimation tendencies were unrelated to other cognitive tendencies or personality traits. In Study 2, we demonstrate that Klee and Kandinsky were also represented differently, but in this case, the intergroup effect was stronger than the category label effect. In Studies 3 and 4, we examined effects of category labels on how participants allocate resources to, evaluate, and ascribe traits to ingroup and outgroup members. We found both category label and intergroup effects when participants were assigned to overestimator and underestimator groups. However, we found only the intergroup effect when participants were assigned to Klee and Kandinsky groups. Together, this work advances but does not upend understanding of minimal group effects. We robustly replicate minimal intergroup bias in mental representations of faces, evaluations, trait inferences, and resource allocations. At the same time, we show that seemingly arbitrary category labels can imply characteristics about groups that may influence responses in intergroup contexts. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Exposure to negative stereotypes influences representations of monetary incentives in the nucleus accumbens.

Contemporary society is saturated with negative representations of racial and ethnic minorities. Social science research finds that exposure to such negative stereotypes creates stress above and beyond pre-existing effects of income inequality and structural racism. Neuroscience studies in animals and humans show that life stress modulates brain responses to rewards. However, it is not known whether contending with negative representations of one's social group spills overs to influence reward processing. We used functional magnetic resonance imaging to examine the effects of stigmatizing negative stereotypes on neural responding to the anticipation and consumption of monetary gains and losses in a Mexican American sample. Machine learning analyses indicated that incentive-related patterns of brain activity within the nucleus accumbens differed between Mexican Americans subjected to negative stereotypes and those who were not. This effect occurred for anticipating both gains and losses. Our work suggests that rhetoric stigmatizing Latinos and other minorities could alter how members of such groups process incentives in their environment. These findings contribute to our understanding of the linkage between stigmatizing experiences and motivated behavior, with implications for well-being and health.

Clinicopathologic Analysis of Lateral Margin Measured by Whole-mount Section in T3 Rectal Cancer.

PURPOSE: Total mesorectal excision is a standard technique for rectal cancer. The whole-mount section can encompass the entire specimen, so it is a more appropriate for measuring circumferential margin than conventional section. We analyzed the clinical characteristics and prognosis based on lateral margins measured by whole-mount sections. MATERIALS AND METHODS: Medical records of patients who were operated on for T3 rectal cancer from 2005 to 2015 were reviewed retrospectively. A total of 154 patients were included. The slides of the whole-mount sections were re-reviewed by a single pathologist. RESULTS: We divided the groups according to the length of the lateral margin (LM: 1mm, 1.5mm and 2mm). There was significantly frequent lymphovascular invasion and N state was higher when LM was short in all groups. There were more micrometastasis in group LM.

Clinical study of colorectal cancer operation: Survival analysis.

Purpose: Overall 5-year survival rates for colon and rectal cancer reported recently by the American Cancer Society were 89%, 90% for localized disease, 71%, 71% for regional disease, and 14%, 15% for distant disease. But the results of survival rate of colorectal cancer in a single institution were very rare. The aim of this study is to evaluate surgical results and survival rates of colorectal cancer. Methods: We conducted a retrospective study with patients who underwent curative resection for a primary colorectal adenocarcinoma between 2009 and 2018. Results: Five-year overall and disease-free survival were 79.5% and 69.9%, respectively. The overall 5-year survival by stages was 94.7% in stage I, 88.4% in stage II, 74.3% in stage III and 31.5% in stage IV. Five-year disease-free survival was 91% in stage I, 79.8% in stage II, 63.3% in stage III, and 18.9% in stage IV. The overall 5-year survival in rectal cancer was superior to colon cancer (P=0.014) while there was no difference in 5-year disease-free survival (P=0.338). Overall survival in female patients was better than male patient (P=0.029). Overall survival by age was worst in group of less than 40 years old (62.5%), and best in group between 41 and 65 years old (86.5%). Postoperative mortality within 30 days was 0.4%, and the recurrence rate was 19.2%. Conclusion: With the development of surgical skills and various treatments, postoperative outcome of colorectal cancer is expected to improve. It may be helpful for surgeons to improve their surgical outcomes when they review their data and conduct active researches.

A soft massage tool is advantageous for compressing deep soft tissue with low muscle tension: Therapeutic evidence for self-myofascial release.

OBJECTIVES: This study aimed to compare the amount of deep tissue pressure and muscle relaxation between a soft inflatable rubber ball (SIRB) and a hard massage ball (HMB). DESIGN: Crossover experimental design study. INTERVENTIONS: Thirty participants with neck pain (age: 65.9 ± 3.4, Neck Disability Index score: 34.0% ± 15.2) pillowed a SIRB or an HMB beneath the suboccipital region in the supine position. For the baseline condition, participants pillowed a foam block without a ball. MAIN OUTCOME MEASURES: To quantify the amount of deep-tissue pressure by a ball, compressed soft tissue thickness was measured with lateral cervical radiographs. To assess muscle relaxation, the amount of muscle tension was determined using electromyography of the sternocleidomastoid and upper trapezius muscles. To monitor the cervical lordosis in each condition, the extension angles of the cervical vertebrae were quantified using the relative rotation angles. RESULTS: The compressed soft tissue thickness in the SIRB condition was significantly lower than that in the HMB condition. The normalised muscle activities exhibited that right sternocleidomastoid muscle activity in the HMB condition was significantly higher than that in the baseline and SIRB conditions. In the SIRB and HMB conditions, Numeric Rating Scale for pain was 0.2 ± 0.5 and 5.2 ± 1.4, respectively. CONCLUSIONS: Our findings demonstrate that a SIRB is more advantageous than an HMB for pressing the soft tissue deeply. This finding would be related to reduced muscle tension and discomfort in the SIRB condition when compared with the HMB condition.

Data from the Human Penguin Project, a cross-national dataset testing social thermoregulation principles.

In the Human Penguin Project (N = 1755), 15 research groups from 12 countries collected body temperature, demographic variables, social network indices, seven widely-used psychological scales and two newly developed questionnaires (the Social Thermoregulation and Risk Avoidance Questionnaire (STRAQ-1) and the Kama Muta Frequency Scale (KAMF)). They were collected to investigate the relationship between environmental factors (e.g., geographical, climate etc.) and human behaviors, which is a long-standing inquiry in the scientific community. More specifically, the present project was designed to test principles surrounding the idea of social thermoregulation, which posits that social networks help people to regulate their core body temperature. The results showed that all scales in the current project have sufficient to good psychometrical properties. Unlike previous crowdsourced projects, this dataset includes not only the cleaned raw data but also all the validation of questionnaires in 9 different languages, thus providing a valuable resource for psychological scientists who are interested in cross-national, environment-human interaction studies.

Optimal Parameters for Intervertebral Disk Resection Using Aqua-Plasma Beams.

OBJECTIVE: A minimally invasive procedure for intervertebral disk resection using plasma beams has been developed. Conventional parameters for the plasma procedure such as voltage and tip speed mainly rely on the surgeon's personal experience, without adequate evidence from experiments. Our objective was to determine the optimal parameters for plasma disk resection. METHODS: Rate of ablation was measured at different procedural tip speeds and voltages using porcine nucleus pulposi. The amount of heat formation during experimental conditions was also measured to evaluate the thermal safety of the plasma procedure. RESULTS: The ablation rate increased at slower procedural speeds and higher voltages. However, for thermal safety, the optimal parameters for plasma procedures with minimal tissue damage were an electrical output of 280 volts root-mean-square (Vrms) and a procedural tip speed of 2.5 mm/s. CONCLUSION: Our findings provide useful information for an effective and safe plasma procedure for disk resection in a clinical setting.

Two-year clinical outcomes of radiofrequency focal ablation using a navigable plasma disc decompression device in patients with lumbar disc herniation: efficacy and complications.

PURPOSE: To report on the 2-year clinical outcomes of focal ablation using a navigable plasma disc decompression device in patients with lumbar herniated nucleus pulposus (HNP). PATIENTS AND METHODS: This was a prospective, single-cohort study conducted in a clinical center. A total of 170 patients with lumbar HNP were assessed for pain intensity using the visual analog scale (VAS), for disability level using the Oswestry Disability Questionnaire (ODI), for health-related quality of life using the short form-36 version 2 of the bodily pain scale (SF-36 BP), and for the angles of passive straight leg raise (SLR) test. The herniated portions of the target discs were ablated using a navigable catheter under a well-instructed protocol with informed consent. Outcome data were prospectively collected before the procedure: 1 week after the procedure: and then 1, 3, 6, 12, and 24 months postoperatively. For statistical analysis, repeated-measures analysis of variance was performed. RESULTS: Two years after the procedure, the mean VAS decreased from 7.1±1.7 to 2.1±1.9, the mean ODI decreased from 50.9±17.2 to 20.3% ± 14.6%, and the mean SF-36 BP increased from 38.8±8.4 to 45.8±9.4 (P<0.05). On the SLR test, the angular change after 2 years improved considerably from 51.2±17.3 to 85.0±9.3 degrees. There was 90%-100% VAS improvement in 25.9% and 50%-90% VAS improvement in 52.4% of the patients; 1.8% experienced pain aggravation compared with the initial VAS. Two subjects showed short-term foot drop, whereas one subject showed the severe complication of foot drop for more than 6 months. The recurrence rate ranged from 4.7% to 11.5%. CONCLUSION: These findings suggest that focal ablation of herniated discs using a navigable disc decompression device is worth considering for relieving pain related to lumbar HNP. However, the development of more advanced technologies and methods for safety and efficiency is necessary.