Effects of Unilateral High Frequency Stimulation of the Subthalamic Nucleus on Risk-avoidant Behavior in a Partial 6-hydroxydopamine Model of Parkinson's Disease.

BACKGROUND: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a well-established treatment for the motor symptoms of Parkinson's disease (PD). While PD is primarily characterized by motor symptoms such as tremor, rigidity, and bradykinesia, it also involves a range of non-motor symptoms, and anxiety is one of the most common. The relationship between PD and anxiety is complex and can be a result of both pathological neural changes and the psychological and emotional impacts of living with a chronic progressive condition. Managing anxiety in PD is critical for improving the patients' quality of life. However, patients undergoing STN DBS can occasionally experience increased anxiety. METHODS: This study investigates changes in risk-avoidant behavior following STN DBS in a pre-motor animal model of PD under chronic and acute unilateral high frequency stimulation. RESULTS: No significant changes in risk-avoidant behaviors were observed in rats who underwent STN DBS compared with sham stimulation controls. Chronic stimulation prevented sensitization in the elevated zero maze. CONCLUSIONS: These results suggest that unilateral stimulation of the STN may have minimal effects on risk-avoidant behaviors in PD. However, additional research is required to fully understand the mechanisms responsible for changes in anxiety during STN DBS for PD.

Effects of topical applications of porcine acellular urinary bladder matrix and Centella asiatica extract on oral wound healing in a rat model.

OBJECTIVES: To evaluate the effects of topical applications of porcine acellular urinary bladder matrix (AUBM) and Centella asiatica extract (CAE) on the healing of tongue wounds in a rat model. MATERIALS AND METHODS: Wounds were made in the tongue using a punch tool in 64 male Sprague-Dawley rats, randomized into four groups (n = 16 per group): group 1 (control), group 2 (CAE), group 3 (AUBM mixed with orabase), and group 4 (orabase). No product was applied in group 1 and groups 2-4 received three daily topical applications. The animals were weighed on day 0 and at the time of euthanasia. Four rats in each group were euthanized at days 2, 7, 14, and 21 and the tongues were processed for: macroscopic morphometric analysis, myeloperoxidase (MPO) and malondialdehyde (MDA) levels, histological wound repair (degree of reepithelialization and inflammation), and CD31 positivity. RESULTS: The animals' weight gain, histological wound repair, and CD31 positivity from greatest to least were: AUBM > CAE > orabase > control. Percentage of tongue occupied by wound, MPO, and MPA levels from least to greatest were: AUBM < CAE < orabase < control, whereby the AUBM group showed significant differences (p ≤ 0.05) in comparison with the other groups on days 2, 7, 14, and 21 for percentage of tongue occupied by wound and MDA and on days 7, 14, and 21 for MPO. CONCLUSIONS: CAE is effective for oral tissue regeneration, while AUBM is an even more potent means of oral mucosa regeneration. CLINICAL RELEVANCE: AUBM may be beneficial to patients with oral wounds; this finding requires further clinical and laboratory investigation.

Isoperistaltic versus antiperistaltic side-to-side anastomosis after right laparoscopic hemicolectomy for cancer (ISOVANTI) trial: study protocol for a randomised clinical trial.

BACKGROUND: It is believed that loosing ileocecal valve is well tolerated in patients who do not have short bowel syndrome or Crohn disease. From the hypothesis of colonic peristalsis and transit is regulated by that ileocecal valvular mechanism, we try to find out if the creation of a new pseudo-valvular mechanism as antiperistaltic anastomosis could be considered after right hemicolectomy can cause any short- or long-term changes in gastrointestinal habits. PURPOSE: The purpose of the study at primary endpoint is to compare early (occurring within 30 days of surgery) and late (occurring during the follow-up) postoperative complications between both groups The purpose of the study at secondary endpoint is to compare intraoperative and postoperative events between experimental and control groups in terms of operating time, first oral tolerance day, first flatus and faeces, length of hospital stay and orocecal transit; comparing rates of gastrointestinal life quality and comparing mortality rates between both groups. METHODS: The ISOVANTI trial is a randomized controlled single-centre trial comparing isoperistaltic versus antiperistaltic side-to-side anastomosis after right laparoscopic hemicolectomy. It is designed as a parallel group superiority trial. CONCLUSIONS: It is unknown if a pseudo-valvular mechanism as antiperistaltic anastomosis can be considered has short- or long-term consequences in gastrointestinal habit. Considering the impact that ileocolic anastomosis configuration could have on the restitution of bowel transit after right hemicolectomy, we think it is indicated and necessary a randomized trial comparing iso- and antiperistaltic modalities. TRIAL REGISTRATION: NCT02309931.

Intracorporeal ileocolic anastomosis in patients with laparoscopic right hemicolectomy.

BACKGROUND: Since the introduction of laparoscopic colorectal surgery, there has been a controversy between creating an intracorporeal or extracorporeal ileocolic anastomosis in right hemicolectomy. The purpose is to report our experience in intracorporeal anastomosis following right hemicolectomy in both malignant and benign pathologies. STUDY DESIGN: A retrospective review of a prospectively collected database was conducted at Virgen de la Arrixaca Clinical University Hospital (Murcia) between January 2000 and April 2014. The study includes all surgery patients who received a laparoscopic right hemicolectomy with an intracorporeal ileocolic anastomosis. The criteria for exclusion were conversion to open surgery during the procedure due to technical difficulties during dissect. Tumours considered T4 were not excluded, nor were stage IV patients or those with a history of previous abdominal surgery. RESULTS: There were 173 patients (63 females) aged 67 (range 14-91) years, with body mass index of 27 (17-52) kg/m(2) and ASA 1:2:3:4 of 12:78:68:15; 41% had previous abdominal surgery and 70% had a pre-existing comorbidity. Operating time was 142 (60-270) min. Specimen extraction site incision length was 8.1 (6-11.1) cm. Conversion rate was 9.2%, and there were 39 complications (22.54%) and 9 reoperations (5.2%). Readmission rate was 5.2%. Length of stay was 5.7 (1-35) days. CONCLUSION: The intracorporeal procedure is a safe and feasible alternative for creating an ileocolic anastomosis. It involves a similar rate of complications and may prevent some of the drawbacks presented by extracorporeal anastomosis.

Mortality and functional status at one-year of follow-up in elderly patients with prolonged ICU stay. / Mortalidad y estado funcional al año de pacientes ancianos con ingreso prolongado en una unidad de cuidados intensivos.

OBJECTIVE: To evaluate mortality and functional status at one year of follow-up in patients>75 years of age who survive Intensive Care Unit (ICU) admission of over 14 days. DESIGN: A prospective observational study was carried out. SETTING: A Spanish medical-surgical ICU. PATIENTS: Patients over 75 years of age admitted to the ICU. PRIMARY VARIABLES OF INTEREST: ICU admission: demographic data, baseline functional status (Barthel index), baseline mental status (Red Cross scale of mental incapacity), severity of illness (APACHE II and SOFA), stay and mortality. One-year follow-up: hospital stay and mortality, functional and mental status, and one-year follow-up mortality. RESULTS: A total of 176 patients were included, of which 22 had a stay of over 14 days. Patients with prolonged stay did not show more ICU mortality than those with a shorter stay in the ICU (40.9% vs 25.3% respectively, P=.12), although their hospital (63.6% vs 33.8%, P<.01) and one-year follow-up mortality were higher (68.2% vs 41.2%, P=.02). Among the survivors, one-year mortality proved similar (87.5% vs 90.6%, P=.57). These patients presented significantly greater impairment of functional status at hospital discharge than the patients with a shorter ICU stay, and this difference persisted after three months. The levels of independence at one-year follow-up were never similar to baseline. No such findings were observed in relation to mental status. CONCLUSIONS: Patients over 75 years of age with a ICU stay of more than 14 days have high hospital and one-year follow-up mortality. Patients who survive to hospital admission did not show greater mortality, though their functional dependency was greater.

Stimulation of the efferent limb before ileostomy closure: a randomized clinical trial.

BACKGROUND: Postoperative ileus is the most common complication after ileostomy closure with an increase in morbidity, hospital stay, and health care costs. OBJECTIVE: The aim of this study is to assess the utility of a new technique for reducing postoperative ileus after protective ileostomy closure. DESIGN: This is a prospective randomized study registered at ClinicalTrials.gov (NCT01881594). Patients were randomly assigned to undergo either stimulation through the efferent limb of the ileostomy before surgery or nonstimulation before surgery. SETTING: This study was conducted at the Department of Surgery of the Virgen de la Arrixaca Clinical University Hospital (Murcia). PATIENTS: Seventy patients underwent surgery for ileostomy closure. In 35 patients, during the 2 weeks before surgery, daily stimulation of the defunctionalized stomal segment was performed by using a thick solution (500 mL of physiological saline associated with 30 g of thickening agent, Nestle Resource, Vevey, Switzerland). In the other 35 patients, stimulation was not performed before surgery. MAIN OUTCOME MEASURES: The primary outcome was postoperative ileus. The secondary outcomes included time to tolerating a diet and postoperative stay. RESULTS: Both groups of patients were homogenous for demographic data, characteristics of the first rectal cancer operation, and intersurgery periods. After ileostomy closure, the stimulated group of patients had an earlier return to oral tolerance (1.06 vs 2.57 days; p = 0.007) and passage of flatus or stool (1.14 vs 2.85 days; p <0.001) than the nonstimulated group of patients. The incidence of postoperative ileus (2.85% vs 20%; p = 0.024) and hospital stay (2.49 vs 4.61 days; p = 0.002) was also lower in the stimulated patients. LIMITATIONS: Small numbers of patients means that no definitive statements can be made regarding the effectiveness of this technique. CONCLUSIONS: Stimulation of the efferent limb of the ileostomy before closure is a safe technique that reduces postoperative ileus and fosters early intestinal transit and oral tolerance with a shorter postoperative hospital stay.

Midbrain dopaminergic degeneration differentially modulates primary motor cortex activity and motor behavior in hemi-parkinsonian rats.

Parkinson's disease (PD) is marked by degeneration in the nigrostriatal dopaminergic pathway, affecting motor control via complex changes in the cortico-basal ganglia-thalamic motor network, including the primary motor cortex (M1). The modulation of M1 neuronal activity by dopaminergic inputs, particularly from the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc), plays a crucial role in PD pathophysiology. This study investigates how nigrostriatal dopaminergic degeneration influences M1 neuronal activity in rats using in vivo calcium imaging. Histological analysis confirmed dopaminergic lesion severity, with high lesion level rats showing significant motor deficits. Levodopa treatment improved fine motor abilities, particularly in high lesion level rats. Analysis of M1 calcium signals based on dopaminergic lesion severity revealed distinct M1 activity patterns. Animals with low dopaminergic lesion showed increased calcium events, while high lesion level rats exhibited decreased activity, partially restored by levodopa. These findings suggest that M1 activity is more sensitive to transient fluctuations in dopaminergic transmission, rather than to chronic high or low dopaminergic signaling. This study underscores the complex interplay between dopaminergic signaling and M1 neuronal activity in PD symptoms development. Further research integrating behavioral and calcium imaging data can elucidate mechanisms underlying motor deficits and therapeutic responses in PD.

The value of 18F-FDG PET/CT for assessing the response to neoadjuvant therapy in locally advanced rectal cancer.

PURPOSE: Neoadjuvant radiochemotherapy (RCT) is an accepted treatment for locally advanced rectal cancer (LARC) that improves surgical outcomes. If a pathological complete response is achieved, conservative surgery can be considered. The objective of our study was to assess the reliability of (18)F-FDG PET/CT for evaluating the response to neoadjuvant RCT in LARC. METHODS: We prospectively studied 41 patients diagnosed with LARC and candidates for neoadjuvant RCT. PET/CT was performed before RCT and again 7 weeks later. A visual and semiquantitative analysis was carried out. The pathological response was classified according to the Mandard tumour regression grade (TRG). We analysed: (a) the relationship between TRG and the result of the posttreatment PET/CT scan, and (b) the correlation between the percentage of pathological response and the percentage decrease in SUVmax according to the response index (RI). RESULTS: The mean SUVmax of the rectal lesions at diagnosis was 13.6 and after RCT 3.96. The mean RI was 65.32 %. Sensitivity was 88.88 %, specificity 92.86 %, positive predictive value 96 %, negative predictive value 81 %. Of the 41 patients, 8 had TRG I (all negative PET/CT); 6 had TRG II (5 negative, 1 positive PET/CT); 16 had TRG III (13 positive, 3 negative PET/CT); 9 had TRG IV (all positive PET/CT); 2 had TRG V (all positive PET/CT). Of the 14 patients classified as responders (TRG I, II), 13 (92.86 %) had negative PET/CT. Of the 27 patients classified as nonresponders (TRG III-V), 24 (88.88 %) had positive PET/CT. Differences were statistically significant (p < 0.0001). The RI in responders was 79.9 % and in nonresponders was 60.3 %. Differences were statistically significant (p < 0.037). CONCLUSION: PET/CT is a reliable technique for assessing response to neoadjuvant RCT in LARC, with a view to considering more conservative surgical treatment. The combination of the visual and semiquantitative analysis increases the diagnostic validity of PET/CT.

Impact of a multidisciplinary team training programme on rectal cancer outcomes in Spain.

AIM: The Spanish Rectal Cancer Project was established in 2006, inspired by the Norwegian Rectal Cancer Project. It consisted of an educational project aiming to introduce mesorectal excision surgery to surgeons, pathologists and radiologists. Its effect on local recurrence (LR) was compared with the Norwegian Project. METHOD: An observational cohort study was carried out including all patients (4700) with rectal cancer from a population of 19 329 992 inhabitants operated on in 51 Spanish hospitals between March 2006 and June 2010. Curative resection was defined as a resection with an uninvolved circumferential margin in patients without distant metastases and without intra-operative rectal perforation. The effectiveness of the programme was measured by a central registry with feedback to participating institutions of their own results compared with the national average. The main outcome measures were LR and adverse effects in curative resections. RESULTS: Of the 4700 patients, 3213 had a resection considered to be curative. LR rates were 4.7% (95% CI 0.03-0.59), metastasis rate was 16% (95% CI 0.14-0.17) and overall survival was 87.8% (95% CI 0.86-0.89). Multivariate analysis showed that advanced TNM stage and decreasing distance of the tumour from the anal verge had a negative influence on LR. CONCLUSION: This study shows that the results obtained in Norway have been reproduced in a larger population in Spain applying a similar methodology.

Laparoscopic versus open surgery for rectal cancer: results of a prospective multicentre analysis of 4,970 patients.

OBJECTIVE: To compare laparoscopic versus open surgery for rectal cancer and analyse the results of the multidisciplinary audited project on total mesorectal excision conducted in Spain. BACKGROUND: The safety and therapeutic efficiency of laparoscopic surgery for rectal cancer are controversial due to the technical difficulties it involves. A deviation from the oncological principles of mesorectal excision would mean a potential increase in local recurrence and shorter survival. METHODS: This prospective non-randomised multicentre study includes 4,970 patients with rectal cancer. The study compares perioperative, postoperative, anatomicopathological and survival variables. RESULTS: Five hundred and sixty five patients were excluded. Of the remaining 4,405, 3,018 (68.51%) had open surgery (OS) and 1,387 (31.49%) laparoscopic surgery (LS). The rate of anterior resections was higher in the LS group. The rate of intraoperative tumour perforation, number of red blood cell concentrates transfused and length of hospital stay were greater in the OS group, whereas surgical time was longer in the LS group. The incidence of complications was 45.6% in the OS group and 38.3% in the LS group. Involvement of the circumferential and distal margin, as well as unsatisfactory and partially satisfactory quality of the mesorectum, were greater in the OS group. There were no differences for local recurrence and survival rates. CONCLUSIONS: According to these results, laparoscopic surgery is the best option for the surgical treatment of rectal cancer, with similar rates of local recurrence and survival, although there are oncological indicators in this study to suggest that these results can be improved with laparoscopic surgery.

Axonal pathways linked to therapeutic and nontherapeutic outcomes during psychiatric deep brain stimulation.

OBJECTIVE: The underlying hypothesis of our work is that specific clinical neuropsychiatric benefits can be achieved by selective activation of specific axonal pathways during deep brain stimulation (DBS). As such, the goal of this study was to develop a method for identifying axonal pathways whose activation is most likely necessary for achieving therapeutic benefits during DBS. EXPERIMENTAL DESIGN: Our approach combined clinical data, diffusion tensor tractography, and computer models of patient-specific neurostimulation to identify particular axonal pathways activated by DBS and determine their correlations with individual clinical outcome measures. We used this method to evaluate a cohort of seven treatment-resistant depression patients treated with DBS of the ventral anterior internal capsule and ventral striatum (VC/VS). PRINCIPAL OBSERVATIONS: Clinical responders exhibited five axonal pathways that were consistently activated by DBS. All five pathways coursed lateral and medial to the VS or dorsal and lateral to the nucleus accumbens; however, details of their specific trajectories differed. Similarly, one common pathway was identified across nonresponders. CONCLUSIONS: Our method and preliminary results provide important background for studies aiming to expand scientific characterization of neural circuitry associated with specific psychiatric outcomes from DBS. Furthermore, identification of pathways linked to therapeutic benefit provides opportunities to improve clinical selection of surgical targets and stimulation settings for DBS devices.

Short-term outcomes of minimally invasive retromuscular ventral hernia repair using an enhanced view totally extraperitoneal (eTEP) approach: systematic review and meta-analysis.

BACKGROUND: The enhanced view totally extraperitoneal (eTEP) approach is becoming increasingly more widely accepted as a promising technique in the treatment of ventral hernia. However, evidence is still lacking regarding the perioperative, postoperative and long-term outcomes of this technique. The aim of this meta-analysis is to summarize the current available evidence regarding the perioperative and short-term outcomes of ventral hernia repair using eTEP. STUDY DESIGN: A systematic search was performed of PubMed, EMBASE, Cochrane Library and Web of Science electronic databases to identify studies on the laparoscopic or robotic-enhanced view totally extraperitoneal (eTEP) approach for the treatment of ventral hernia. A pooled meta-analysis was performed. The primary end point was focused on short-term outcomes regarding perioperative characteristics and postoperative parameters. RESULTS: A total of 13 studies were identified involving 918 patients. Minimally invasive eTEP resulted in a rate of surgical site infection of 0% [95% CI 0.0-1.0%], a rate of seroma of 5% [95% CI 2.0-8.0%] and a rate of major complications (Clavien-Dindo III-IV) of 1% [95% CI 0.0-3.0%]. The rate of intraoperative complications was 2% [95% CI 0.0-4.0%] with a conversion rate of 1.0% [95% CI 0.0-3.0%]. Mean hospital length of stay was 1.77 days [95% CI 1.21-2.24]. After a median follow-up of 6.6 months (1-24), the rate of recurrence was 1% [95% CI 0.0-1.0%]. CONCLUSION: Minimally invasive eTEP is a safe and effective approach for ventral hernia repair, with low reported intraoperative complications and good outcomes.

Integral methods for automatic quantification of fast-scan-cyclic-voltammetry detected neurotransmitters.

Modern techniques for estimating basal levels of electroactive neurotransmitters rely on the measurement of oxidative charges. This requires time integration of oxidation currents at certain intervals. Unfortunately, the selection of integration intervals relies on ad-hoc visual identification of peaks on the oxidation currents, which introduces sources of error and precludes the development of automated procedures necessary for analysis and quantification of neurotransmitter levels in large data sets. In an effort to improve charge quantification techniques, here we present novel methods for automatic selection of integration boundaries. Our results show that these methods allow quantification of oxidation reactions both in vitro and in vivo and of multiple analytes in vitro.

Defining a Path Toward the Use of Fast-Scan Cyclic Voltammetry in Human Studies.

Fast Scan Cyclic Voltammetry (FSCV) has been used for decades as a neurochemical tool for in vivo detection of phasic changes in electroactive neurotransmitters in animal models. Recently, multiple research groups have initiated human neurochemical studies using FSCV or demonstrated interest in bringing FSCV into clinical use. However, there remain technical challenges that limit clinical implementation of FSCV by creating barriers to appropriate scientific rigor and patient safety. In order to progress with clinical FSCV, these limitations must be first addressed through (1) appropriate pre-clinical studies to ensure accurate measurement of neurotransmitters and (2) the application of a risk management framework to assess patient safety. The intent of this work is to bring awareness of the current issues associated with FSCV to the scientific, engineering, and clinical communities and encourage them to seek solutions or alternatives that ensure data accuracy, rigor and reproducibility, and patient safety.

Motivating Self-Efficacy in Diverse Biomedical Science Post-baccalaureate and Graduate Students Through Scientific Conference Implementation.

Tactics to increase the number of underrepresented (UR) students in biomedical research PhD training programs have not yet translated to UR faculty numbers that reflect the diversity of the United States. Continued interventions are required to build skills beyond those that result in placement into a PhD program. We hypothesize that successful interventions must build skills that give UR students foundations for confident self-efficacy in leadership. We seek interventions that allow UR students to envision themselves as successful faculty. We posit that development of such skills is difficult in the classroom or laboratory alone. Therefore, novel interventions are required. As part of the NIH-funded Post-baccalaureate Research Education Program (PREP) and Initiative for Maximizing Student Development (IMSD) at the Mayo Clinic Graduate School of Biomedical Sciences, we designed and implemented a unique intervention to support development of student leadership skills: a biannual student-organized and student-led national research conference titled "Scientific Innovation Through Diverse Perspectives" (SITDP). This initiative is based on the concept that students who actively live out realistic roles as scientific leaders will be encouraged to persist to scientific leadership as faculty. Here we describe the motivation for, design of, and outcomes from, the first three pilot conferences of this series. We further discuss approaches needed to rigorously evaluate the effectiveness of such interventions in the future.

Adrenomedullin as a potential biomarker involved in patients with hereditary hemorrhagic telangiectasia.

BACKGROUND: Adrenomedullin (AM) is a vasoactive peptide mostly secreted by endothelial cells with an important role in preserving endothelial integrity.  The relationship between AM and hereditary hemorrhagic telangiectasia (HHT) is unknown. We aimed to compare the serum levels and tissue expression of AM between HHT patients and controls. METHODS: Serum AM levels were measured by radioimmunoassay and compared between control and HHT groups. AM levels were also compared among HHT subgroups according to clinical characteristics. The single nucleotide polymorphism (SNP) rs4910118 was assessed by restriction analysis and sequencing. AM immunohistochemistry was performed on biopsies of cutaneous telangiectasia from eight HHT patients and on the healthy skin from five patients in the control group. RESULTS: Forty-five HHT patients and 50 healthy controls were included, mean age (SD) was 50.7 (14.9) years and 46.4 (9.9) years (p = 0.102), respectively. HHT patients were mostly female (60% vs 38%, p = 0.032). Median [Q1-Q3] serum AM levels were 68.3 [58.1-80.6] pg/mL in the HHT group and 47.7 [43.2-53.8] pg/mL in controls (p<0.001), with an optimal AM cut-off according to Youden's J statistic of 55.32 pg/mL (J:0.729). Serum AM levels were similar in the HHT subgroups. No patient with HHT had the SNP rs4910118. AM immunoreactivity was found with high intensity in the abnormal blood vessels of HHT biopsies. CONCLUSIONS: We detected higher AM serum levels and tissue expression in patients with HHT than in healthy controls. The role of AM in HHT, and whether AM may constitute a novel biomarker and therapeutic target, needs further investigation.

Quality of mesorectum after laparoscopic resection for rectal cancer - results of an audited teaching programme in Spain.

OBJECTIVE: The aim of this prospective observational study was to compare the quality of total mesorectal excision between laparoscopic and open surgery for rectal cancer. METHOD: In April 2006, the Spanish Association of Surgeons started an audited teaching programme. The project was similar to the Norwegian one and several training courses were arranged. Patients were classified into two groups: laparoscopic rectal resection (LR) and open rectal resection (OR). The quality of the mesorectum was scored: complete, nearly complete or incomplete. The circumferential margin (CRM) was considered positive, if tumour was located 1 mm or less from the surface of the specimen. RESULTS: Between 2006 and 2008, 604 patients underwent rectal resection with total mesorectal excision for rectal cancer: 209 patients were included in the LR group and 395 patients in the OR group. There were no differences in terms of number of lymph nodes affected, distance of the tumour from CRM. The mesorectum was complete in 464 (76.8%), nearly complete in 91 (15.1%) and incomplete in 49 patients (8.1%). CRM was negative in 534 patients (88.4%). No differences were observed between the two groups. The overall postoperative morbidity rate was 38.8% in LR group and 44.6% in OR group (P = 0.170). Overall postoperative mortality rate was 2.5%. One patient died (0.5%) in the LR group and 14 patients died (3.5%) in the OR group (P = 0.021). CONCLUSION: Laparoscopic resection for rectal cancer is feasible with the quality of mesorectal excision and postoperative outcomes similar to those of open surgery.

Simultaneous Ca2+ Imaging and Optogenetic Stimulation of Cortical Astrocytes in Adult Murine Brain Slices.

Astrocytes are actively involved in a neuroprotective role in the brain, which includes scavenging reactive oxygen species to minimize tissue damage. They also modulate neuroinflammation and reactive gliosis prevalent in several brain disorders like epilepsy, Alzheimer's, and Parkinson's disease. In animal models, targeted manipulation of astrocytic function via modulation of their calcium (Ca2+ ) oscillations by incorporating light-sensitive cation channels like Channelrhodopsin-2 (ChR2) offers a promising avenue in influencing the long-term progression of these disorders. However, using adult animals for Ca2+ imaging poses major challenges, including accelerated deterioration of in situ slice health and age- related changes. Additionally, optogenetic preparations necessitate usage of a red-shifted Ca2+ indicator like Rhod-2 AM to avoid overlapping light issues between ChR2 and the Ca2+ indicator during simultaneous optogenetic stimulation and imaging. In this article, we provide an experimental setting that uses live adult murine brain slices (2-5 months) from a knock-in model expressing Channelrhodopsin-2 (ChR2(C128S)) in cortical astrocytes, loaded with Rhod-2 AM to elicit robust Ca2+ response to light stimulation. We have developed and standardized a protocol for brain extraction, sectioning, Rhod-2 AM loading, maintenance of slice health, and Ca2+ imaging during light stimulation. This has been successfully applied to optogenetically control adult cortical astrocytes, which exhibit synchronous patterns of Ca2+ activity upon light stimulation, drastically different from resting spontaneous activity. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Experimental preparation, setup, slice preparation and Rhod-2 AM staining Basic Protocol 2: Image acquisition and analysis.