Novel PAX3::MAML3 fusion identified in alveolar rhabdomyosarcoma, using DNA methylation profiling to expand the genetic spectrum of "fusion-positive" cases.

Alveolar rhabdomyosarcoma (ARMS) with FOXO1 gene rearrangements is an aggressive pediatric rhabdomyosarcoma subtype that is prognostically distinct from embryonal rhabdomyosarcoma and fusion-negative ARMS. Herein, we report two cases of ARMS with PAX3::MAML3 fusions. The tumors arose in an infant and an adolescent as stage IV metastatic disease (by Children's Oncology Group staging system). Histologically, both cases were small round blue cell tumors arranged in vague nests and solid sheets that were diffusely positive for desmin and myogenin. By methylation profiling and unsupervised clustering analysis, the tumors clustered with ARMS with classic FOXO1 rearrangements and ARMS with variant PAX3::NCOA1/INO80D fusions, but not with biphenotypic sinonasal sarcoma (BSNS) with PAX3::MAML3/NCOA2/FOXO1/YAP1 fusions, nor with other small round blue cell tumors, including embryonal rhabdomyosarcoma. The differentially methylated genes between ARMS and BSNS were highly enriched in genes involved in myogenesis, and 21% of these genes overlap with target genes of the PAX3::FOXO1 fusion transcription factor. On follow-up after initiation of vincristine/actinomycin/cyclophosphamide chemotherapy, the tumors showed partial and complete clinical response, consistent with typical upfront chemotherapy responsiveness of ARMS with the classic FOXO1 rearrangement. We conclude that PAX3::MAML3 is a novel variant fusion of ARMS, which displays a methylation signature distinct from BSNS despite sharing similar PAX3 fusions. These findings highlight the utility of methylation profiling in classifying ARMS with non-canonical fusions.

Uterine Sarcoma With EML4::NTRK3 Fusion: A Spectrum of Mesenchymal Neoplasms Harboring Actionable Gene Fusions.

NTRK gene fusions are part of a paradigm shift in oncology, arising as one of the main genomic alterations with actionability in the so-called "agnostic setting." In gynecologic pathology, the recent description of uterine sarcoma resembling fibrosarcoma and with NTRK rearrangements ( NTRK -rearranged uterine sarcoma) highlights the importance of recognizing clinicopathological cues that can lead to genomic profiling. Herein, we report the case of a 43-year-old woman presenting with vaginal bleeding and pelvic mass. Histopathology of the tumor showed moderately atypical spindle cells arranged in long fascicles reminiscent of fibrosarcoma, along with immunohistochemical positivity for S100, CD34, and pan-tropomyosin receptor kinase. This prompted RNA-sequencing and the finding of a rare EML4::NTRK3 fusion. Clinical, histologic, and molecular findings are described, in addition to discussions regarding differential diagnoses and possible implications of the findings in clinical practice.

Prevalence and clinical implications of germline pathogenic variants in cancer predisposing genes in young patients across sarcoma subtypes.

BACKGROUND: Sarcomas are a rare and diverse group of cancers occurring mainly in young individuals for which an underlying germline genetic cause remains unclear in most cases. METHODS: Germline DNA from 177 children, adolescents and young adults with soft tissue or bone sarcomas was tested using multigene panels with 113 or 126 cancer predisposing genes (CPGs) to describe the prevalence of germline pathogenic/likely pathogenic variants (GPVs). Subsequent testing of a subset of tumours for loss of heterozygosity (LOH) evaluation was performed to investigate the clinical and molecular significance of these variants. RESULTS: GPVs were detected in 21.5% (38/177) of the patients (15.8% in children and 21.6% in adolescents and young adults), with dominant CPGs being altered in 15.2% overall. These variants were found in genes previously associated with the risk of developing sarcomas (TP53, RB1, NF1, EXT1/2) but also in genes where that risk is still emerging/limited (ERCC2, TSC2 and BRCA2) or unknown (PALB2, RAD50, FANCM and others). The detection rates of GPVs varied from 0% to 33% across sarcoma subtypes and GPV carriers were more likely to present more than one primary tumour than non-carriers (21.1%×6.5%; p=0.012). Loss of the wild-type allele was detected in 48% of tumours from GPV carriers, mostly in genes definitively associated with sarcoma risk. CONCLUSION: Our findings reveal that a high proportion of young patients with sarcomas presented a GPV in a CPG, underscoring the urgency of establishing appropriate genetic screening strategies for these individuals and their families.

Strong OLIG2 expression in supratentorial ependymoma, ZFTA fusion-positive: A potential diagnostic pitfall.

Ependymomas (EPN) are central nervous system neoplasms that exhibit an ependymal phenotype. In particular, supratentorial EPN (ST-EPN) must be differentiated from more aggressive entities such as glioblastoma, IDH-wildtype. This task is frequently addressed with the use of immunohistochemistry coupled with clinical presentation and morphological features. Here we describe the case of a young adult presenting with migraine-like symptoms and a temporoinsular-based expansile mass that was first diagnosed as a GBM, mostly based on strong and diffuse oligodendrocyte transcription factor 2 (OLIG2) expression. Molecular characterization revealed a ZFTA::RELA fusion, supporting the diagnosis of ST-EPN, ZFTA fusion-positive. OLIG2 expression is rarely reported in tumors other than GBM and oligodendrocyte-lineage committed neoplasms. The patient was treated with radiotherapy and temozolomide after surgery and was alive and well at follow-up. This report illustrates the need to assess immunostains within a broader clinical, morphological and molecular context to avoid premature exclusion of important differential diagnoses.

Establishment and Comprehensive Molecular Characterization of an Immortalized Glioblastoma Cell Line from a Brazilian Patient.

Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults, with few effective treatment strategies. The research on the development of new treatments is often constrained by the limitations of preclinical models, which fail to accurately replicate the disease's essential characteristics. Herein, we describe the obtention, molecular, and functional characterization of the GBM33 cell line. This cell line belongs to the GBM class according to the World Health Organization 2021 Classification of Central Nervous System Tumors, identified by methylation profiling. GBM33 expresses the astrocytic marker GFAP, as well as markers of neuronal origin commonly expressed in GBM cells, such as ßIII-tubulin and neurofilament. Functional assays demonstrated an increased growth rate when compared to the U87 commercial cell line and a similar sensitivity to temozolamide. GBM33 cells retained response to serum starvation, with reduced growth and diminished activation of the Akt signaling pathway. Unlike LN-18 and LN-229 commercial cell lines, GBM33 is able to produce primary cilia upon serum starvation. In summary, the successful establishment and comprehensive characterization of this GBM cell line provide researchers with invaluable tools for studying GBM biology, identifying novel therapeutic targets, and evaluating the efficacy of potential treatments.

Effective Connectivity and Bias Entropy Improve Prediction of Dynamical Regime in Automata Networks.

Biomolecular network dynamics are thought to operate near the critical boundary between ordered and disordered regimes, where large perturbations to a small set of elements neither die out nor spread on average. A biomolecular automaton (e.g., gene, protein) typically has high regulatory redundancy, where small subsets of regulators determine activation via collective canalization. Previous work has shown that effective connectivity, a measure of collective canalization, leads to improved dynamical regime prediction for homogeneous automata networks. We expand this by (i) studying random Boolean networks (RBNs) with heterogeneous in-degree distributions, (ii) considering additional experimentally validated automata network models of biomolecular processes, and (iii) considering new measures of heterogeneity in automata network logic. We found that effective connectivity improves dynamical regime prediction in the models considered; in RBNs, combining effective connectivity with bias entropy further improves the prediction. Our work yields a new understanding of criticality in biomolecular networks that accounts for collective canalization, redundancy, and heterogeneity in the connectivity and logic of their automata models. The strong link we demonstrate between criticality and regulatory redundancy provides a means to modulate the dynamical regime of biochemical networks.

Effectiveness of Intrarectal Povidone-iodine Cleansing Plus Formalin Disinfection of the Needle Tip in Decreasing Infectious Complications After Transrectal Prostate Biopsy: A Randomized Controlled Trial.

PURPOSE: Prostate biopsy is mostly performed through the transrectal route worldwide and infectious complications may occur in up to 7% of cases. Therefore, alternative strategies to decrease infectious complications are needed. Our aim was to evaluate the effectiveness of intrarectal povidone-iodine cleansing plus formalin disinfection of the needle tip in decreasing infectious complications after transrectal ultrasound guided prostate biopsy. MATERIALS AND METHODS: We conducted a prospective, single-center, phase III trial in patients undergoing transrectal ultrasound guided prostate biopsy randomized 1:1 to rectal mucosa cleansing with gauze soaked in 10% povidone-iodine solution wrapped around the gloved index finger and needle tip disinfection by immersion in a 10% formalin solution before each puncture vs control group. The primary end point was the rate of infectious complications defined as 1 or more of the following events: fever, urinary tract infection, or sepsis. RESULTS: Overall, 633 patients were randomized to the intervention group and 623 to the control group. The infectious complication rate was 3.9% in the intervention group and 6.4% in the control group (RR 0.61; 95% CI 0.36-0.99; P = .049). The rates of sepsis, urinary tract infection, and fever were 0.3% vs 0.5% (P = .646), 2.3% vs 4.1% (P = .071), and 1.3% vs 1.9% (P = .443), respectively. The positive urine culture rate was 5.2% in the intervention group and 9% in the control group (RR 0.57; P = .015). There was no statistically significant difference between the groups regarding the occurrence of noninfectious adverse events. CONCLUSIONS: Intrarectal povidone-iodine cleansing plus formalin disinfection of the biopsy needle tip was associated with a reduction in infectious complications after transrectal prostate biopsy.

Introduction of SARS-CoV-2 C.37 (WHO VOI lambda) in the Sao Paulo State, Southeast Brazil.

The Lambda variants of interest (VOI) (C37/GR/452Q.V1/21G) was initially reported in Lima, Peru but has gained rapid dissemination through other Latin American countries. Nevertheless, the dissemination and molecular epidemiology of the Lambda VOI in Brazil is unknown apart from a single case report. In this respect, we characterized the circulation of the SARS-CoV-2 Lambda VOI (C37/GR/452Q.V1/21G) in Sao Paulo State, Brazil. From March to June 2021, we identified seven Lambda isolates in a set of approximately 8000 newly sequenced genomes of the Network for Pandemic Alert of Emerging SARS-CoV-2 variants from Sao Paulo State. Interestingly, in three of the positive patients, the Lambda VOI infection was probably related to a contact transmission. These individuals were fully vaccinated to COVID-19 and presented mild symptoms. The remaining positive for Lambda VOI individuals showed different levels of COVID-19 symptoms and one of them needed hospitalization (score 5, WHO). In our study, we present a low level of Lambda VOI circulation in the Sao Paulo State. This reinforces the essential role of molecular surveillance for the effective SARS-CoV-2 pandemic response, especially in regard to circulating variants.

SARS-COV-2 genomic monitoring in the state of São Paulo unveils two emerging AY.43 sublineages.

Delta VOC is highly diverse with more than 120 sublineages already described as of November 30, 2021. In this study, through active monitoring of circulating severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants in the state of São Paulo, southeast Brazil, we identified two emerging sublineages from the ancestral AY.43 strain which were classified as AY.43.1 and AY.43.2. These sublineages were defined by the following characteristic nonsynonymous mutations ORF1ab:A4133V and ORF3a:T14I for the AY.43.1 and ORF1ab:G1155C for the AY.43.2 and our analysis reveals that they might have a likely-Brazilian origin. Much is still unknown regarding their dissemination in the state of São Paulo and Brazil as well as their potential impact on the ongoing vaccination process. However, the results obtained in this study reinforce the importance of genomic surveillance activity for timely identification of emerging SARS-CoV-2 variants which can impact the ongoing SARS-CoV-2 vaccination and public health policies.

Nanoflowers: A New Approach of Enzyme Immobilization.

Enzymes are biocatalysts known for versatility, selectivity, and brand operating conditions compared to chemical catalysts. However, there are limitations to their large-scale application, such as the high costs of enzymes and their low stability under extreme reaction conditions. Immobilization techniques can efficiently solve these problems; nevertheless, most current methods lead to a significant loss of enzymatic activity and require several steps of activation and functionalization of the supports. In this context, a new form of immobilization has been studied: forming organic-inorganic hybrids between metal phosphates as inorganic parts and enzymes as organic parts. Compared to traditional immobilization methods, the advantages of these nanomaterials are high surface area, simplicity of synthesis, high stability, and catalytic activity. The current study presents an overview of organic-inorganic hybrid nanoflowers and their applications in enzymatic catalysis.

Entropic Dynamics on Gibbs Statistical Manifolds.

Entropic dynamics is a framework in which the laws of dynamics are derived as an application of entropic methods of inference. Its successes include the derivation of quantum mechanics and quantum field theory from probabilistic principles. Here, we develop the entropic dynamics of a system, the state of which is described by a probability distribution. Thus, the dynamics unfolds on a statistical manifold that is automatically endowed by a metric structure provided by information geometry. The curvature of the manifold has a significant influence. We focus our dynamics on the statistical manifold of Gibbs distributions (also known as canonical distributions or the exponential family). The model includes an "entropic" notion of time that is tailored to the system under study; the system is its own clock. As one might expect that entropic time is intrinsically directional; there is a natural arrow of time that is led by entropic considerations. As illustrative examples, we discuss dynamics on a space of Gaussians and the discrete three-state system.

Marginal zone lymphoma of the dura - two case reports with long-term follow-up.

Primary MALT lymphoma arising at the dura is a rare circumstance with no categorical therapeutic plan in literature. There are few reports available with different treatment courses. Here, we report two cases with a long-term follow-up after the same pattern of management and review the literature.

Intracranial cellular schwannomas: a clinicopathological study of 20 cases.

AIMS: Cellular schwannoma is a specific subtype of schwannoma, prone to misinterpretation as a malignant neoplasm. Involvement of the intracranial compartment by these tumours is extremely rare. We aim to characterise this clinicopathological subgroup. METHODS AND RESULTS: We identified a total of 20 cellular schwannomas with predominant intracranial involvement. The mean age of the patients at the time of surgery was 37 years (range = 16-81), with a slight female predominance (1.5:1 ratio). The most common sites were the eighth (n = 8) and fifth (n = 6) cranial nerves. Three tumours involved the anterior cranial fossa/olfactory groove, and a single case involved the glossopharyngeal nerve. All tumours met established criteria for cellular schwannoma, and were composed of interlacing fascicles of spindle cells lacking Verocay bodies with minimal Antoni B pattern and variable chronic inflammation and foamy histiocytes. Rare findings included haemosiderin deposition (n = 6), necrosis (n = 4), brisk mitotic activity (>10 mitoses per 10 high-power fields) (n = 2), focal epithelioid morphology (n = 2), myxoid areas (n = 2), neuroblastoma-like pattern (n = 1) and granular cells (n = 1). Immunohistochemical stains demonstrated expression of Schwann cell markers (S100 protein, SOX10, collagen IV) and preserved H3 K27 trimethylation in all cases tested. Fourteen patients had postoperative follow-up, ranging from 2 months to 21 years (mean = 66 months). In patients with follow-up, local recurrence/persistence developed in six cases; five tumours were initially incompletely resected. No metastatic disease or deaths were reported. CONCLUSIONS: Intracranial cellular schwannomas share morphological and immunophenotypical features with cellular schwannomas at others sites may demonstrate locally aggressive growth but appear to lack metastatic potential.

Brazilian consensus on the diagnosis and treatment of extremities soft tissue sarcomas.

INTRODUCTION: Soft tissue sarcomas (STSs) are rare tumors and constitute only 1% of all tumors in adults. Indeed, due to their rarity, most cases in Brazil are not treated according to primary international guidelines. METHODS: This consensus addresses the treatment of STSs in the extremities. It was made by workgroups from Brazilian Societies of Surgical Oncology, Orthopaedics, Clinical Oncology, Pathology, Radiology and Diagnostic Imaging, and Radiation Oncology. The workgroups based their arguments on the best level of evidence in the literature and recommendations were made according to diagnosis, staging, and treatment of STSs. A meeting was held with all the invited experts and the topics were presented individually with the definition of the degree of recommendation, based on the levels of evidence in the literature. RESULTS: Risk factors and epidemiology were described as well as the pathological aspects and imaging. All recommendations are described with the degree of recommendation and levels of evidence. CONCLUSION: Recommendations based on the best literature regional aspects were made to guide professionals who treat STS. Separate consensus on specific treatments for retroperitoneal, visceral, trunk, head and neck sarcomas, and gastrointestinal stromal tumor, are not contemplated into this consensus.

Gas chromatography-mass spectrometry untargeted profiling of non-Hodgkin's lymphoma urinary metabolite markers.

Non-Hodgkin's lymphoma (NHL) is a cancer of the lymphatic system where the lymphoid and hematopoietic tissues are infiltrated by malignant neoplasms of B, T, and natural killer lymphocytes. Effective and less invasive methods for NHL screening are urgently needed. Herein, we report an untargeted gas chromatography-mass spectrometry (GC-MS) method to investigate metabolic changes in non-volatile derivatized compounds from urine samples of NHL patients (N = 15) and compare them to healthy controls (N = 34). Uni- and multivariate data analysis showed 18 endogenous metabolites, including amino acids and their metabolites, sugars, small organic acids, and vitamins, as statistically significant for group differentiation. A receiver operating characteristic curve (ROC) generated from a support vector machine (SVM) algorithm-based model achieved 0.998 of predictive accuracy, displaying the potential and relevance of GC-MS-detected urinary non-volatile compounds for predictive purposes. Furthermore, a specific panel of key metabolites was also evaluated, showing similar results. All in all, our results indicate that this robust GC-MS method is an effective screening tool for NHL diagnosis and it is able to highlight different pathways of the disease. Graphical Abstract.

Epithelioid Rhabdomyosarcoma: Report of a Cutaneous Case and Literature Review of a Recently Described Variant of Rhabdomyosarcoma.

Rhabdomyosarcoma affects mainly pediatric patients and is currently classified into 4 categories: embryonal, alveolar, pleomorphic, and spindle cell/sclerosing. Epithelioid rhabdomyosarcoma is a recently described variant of rhabdomyosarcoma in which primary cutaneous presentation is infrequent. In this brief report, we describe a rare case of epithelioid rhabdomyosarcoma in an 81-year-old man, presenting as a skin lesion in the neck, which increased in size in 1 month. After imaging evaluation, a solid cervical mass was discovered. A biopsy was performed, and the diagnosis of epithelioid rhabdomyosarcoma was rendered. The patient died due to rapid progression of the tumor. To make an accurate diagnosis and ensure appropriate patient management, it is necessary to be aware of this variant and use proper immunohistochemical stains when facing an epithelioid malignancy, expanding the differential diagnosis of epithelioid neoplasms.

FASTEN IIoT: An Open Real-Time Platform for Vertical, Horizontal and End-To-End Integration.

The Industry 4.0 paradigm, since its initial conception in Germany in 2011, has extended its scope and adoption to a broader set of technologies. It is being considered as the most vital mechanism in the production systems lifecycle. It is the key element in the digital transformation of manufacturing industry all over the world. This scenario imposes a set of major unprecedented challenges which require to be overcome. In order to enable integration in horizontal, vertical, and end-to-end formats, one of the most critical aspects of this digital transformation process consists of effectively coupling digital integrated service/products business models with additive manufacturing processes. This integration is based upon advanced AI-based tools for decentralized decision-making and for secure and trusted data sharing in the global value. This paper presents the FASTEN IIoT Platform, which targets to provide a flexible, configurable, and open solution. The platform acts as an interface between the shop floor and the industry 4.0 advanced applications and solutions. Examples of these efforts comprise management, forecasting, optimization, and simulation, by harmonizing the heterogeneous characteristics of the data sources involved while meeting real-time requirements.

Remote ischemic conditioning enhances heart and brain antioxidant defense.

BACKGROUND: Ischemia-reperfusion injury contributes to morbidity after revascularization procedures. Along with early reperfusion, tissue conditioning by alternating intervals of brief ischemia-reperfusion episodes is considered the best approach to limit tissue damage. Remote ischemic conditioning is conducted remotely, in tissues other than those under ischemia. Despite this, remote ischemic conditioning protection mechanisms are poorly understood, which can lead to misapplication. OBJECTIVES: To assess whether remote ischemic conditioning works in the heart and brain through enhancement of cells' antioxidant defenses and whether the response is sustained or temporary. METHODS: Twenty-one male Wistar rats were assigned to three groups (n = 7): SHAM: same procedure as the other groups, but no remote ischemic conditioning was carried out. RIC 10: heart and brain were harvested 10 minutes after the remote ischemic conditioning protocol. RIC 60: heart and brain were harvested 60 minutes after the remote ischemic conditioning protocol. The remote ischemic conditioning protocol consisted of 3 cycles of 5 min left hindlimb ischemia followed by 5 min left hindlimb perfusion, lasting 30 min in total. Heart and brain samples were used to measure the tissue antioxidant capacity. RESULTS: Remote ischemic conditioning increased heart and brain antioxidant capacity after 10 minutes (0.746 ± 0.160/0.801 ± 0.227 mM/L) when compared to SHAM (0.523 ± 0.078/0.404 ± 0.124 mM/L). No enhancement of heart or brain antioxidant capacity was detected 60 minutes after remote ischemic conditioning (0.551 ± 0.073/0.455 ± 0.107 mM/L). CONCLUSIONS: Remote ischemic conditioning temporarily enhances heart and brain antioxidant defenses in male Wistar rats.

CONTEXTO: A lesão de isquemia e reperfusão contribui para a morbidade após procedimentos de revascularização. Juntamente com a reperfusão precoce, o condicionamento tecidual através de breves episódios de isquemia e reperfusão é considerado a melhor abordagem para limitar o dano tecidual. Apesar disso, os mecanismos do condicionamento isquêmico remoto são pouco compreendidos, o que pode levar a uma aplicação incorreta. OBJETIVOS: Avaliar se o condicionamento isquêmico remoto funciona no coração e no cérebro através do aprimoramento da defesa antioxidante das células e se é uma resposta sustentada ou temporária. MÉTODOS: Vinte e um ratos Wistar foram divididos em três grupos (n = 7): SHAM, no qual não foi realizado condicionamento isquêmico; RIC 10, no qual 10 minutos após o protocolo de condicionamento isquêmico, foi realizada a coleta dos órgãos; e RIC 60, no qual 60 minutos após o protocolo de condicionamento isquêmico, foi realizada a coleta dos órgãos. O protocolo de condicionamento isquêmico remoto consistiu em três ciclos de 5 minutos de isquemia, seguidos de 5 minutos de perfusão no membro posterior esquerdo, com duração total de 30 minutos. Amostras foram usadas para medir a capacidade antioxidante do tecido. RESULTADOS: O condicionamento isquêmico remoto aumentou a capacidade antioxidante do coração e do cérebro após 10 minutos (0,746 ± 0,160/0,801 ± 0,227 mM/L) quando comparado ao SHAM (0,523 ± 0,078/0,404 ± 0,124 mM/L) . Sessenta minutos após o condicionamento isquêmico remoto, não foi detectado aumento da capacidade antioxidante do coração ou do cérebro (0,551 ± 0,073/0,455 ± 0,107 mM/L). CONCLUSÕES: O condicionamento isquêmico remoto melhora temporariamente as defesas antioxidantes do coração e do cérebro em ratos Wistar.

Retraction notice to "Obesity-Induced Increase in Tumor Necrosis Factor-α Leads to Development of Colon Cancer in Mice" Gastroenterology 2012;143:741-753.e4.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief and Deputy Editor-in-Chief following an investigation into the data that were presented in several figures within the article. A number of images used in this article are believed to be duplicated images. The authors stated that they inadvertently inserted images of the wrong blots in several of the figures, resulting in the duplications; however, they did not address all of the concerns raised. Because the editors were no longer confident in the conclusions of the article based on these incorrect data, a decision was made to retract the paper. All authors have been notified of this decision. The University of Campinas (UNICAMP) in São Paulo, Brazil was contacted regarding these concerns, but to date the journal has received no response.

Morphofunctional evaluation of end-to-side neurorrhaphy through video system magnification.

BACKGROUND: The surgical microscope is an essential tool for microsurgery. Nonetheless, several promising alternatives are being developed, including endoscopes and laparoscopes with video systems. However, these alternatives have only been used for arterial anastomoses so far. The aim of this study was to evaluate the use of a low-cost video-assisted magnification system in end-to-side neurorrhaphy in rats. MATERIALS AND METHODS: Forty rats were randomly divided into four matched groups: (1) normality (sciatic nerve was exposed but was kept intact); (2) denervation (fibular nerve was sectioned, and the proximal and distal stumps were sutured-transection without repair); (3) microscope; and (4) video system (fibular nerve was sectioned; the proximal stump was buried inside the adjacent musculature, and the distal stump was sutured to the tibial nerve). Microsurgical procedures were performed with guidance from a microscope or video system. We analyzed weight, nerve caliber, number of stitches, times required to perform the neurorrhaphy, muscle mass, peroneal functional indices, latency and amplitude, and numbers of axons. RESULTS: There were no significant differences in weight, nerve caliber, number of stitches, muscle mass, peroneal functional indices, or latency between microscope and video system groups. Neurorrhaphy took longer using the video system (P < 0.05). The amplitude was higher in the microscope group than in the video group. CONCLUSIONS: It is possible to perform an end-to-side neurorrhaphy in rats through video system magnification. The success rate is satisfactory and comparable with that of procedures performed under surgical microscopes.