Beyond a Transmission Cable-New Technologies to Reveal the Richness in Axonal Electrophysiology.

The axon is a neuronal structure capable of processing, encoding, and transmitting information. This assessment contrasts with a limiting, but deeply rooted, perspective where the axon functions solely as a transmission cable of somatodendritic activity, sending signals in the form of stereotypical action potentials. This perspective arose, at least partially, because of the technical difficulties in probing axons: their extreme length-to-diameter ratio and intricate growth paths preclude the study of their dynamics through traditional techniques. Recent findings are challenging this view and revealing a much larger repertoire of axonal computations. Axons display complex signaling processes and structure-function relationships, which can be modulated via diverse activity-dependent mechanisms. Additionally, axons can exhibit patterns of activity that are dramatically different from those of their corresponding soma. Not surprisingly, many of these recent discoveries have been driven by novel technology developments, which allow for in vitro axon electrophysiology with unprecedented spatiotemporal resolution and signal-to-noise ratio. In this review, we outline the state-of-the-art in vitro toolset for axonal electrophysiology and summarize the recent discoveries in axon function it has enabled. We also review the increasing repertoire of microtechnologies for controlling axon guidance which, in combination with the available cutting-edge electrophysiology and imaging approaches, have the potential for more controlled and high-throughput in vitro studies. We anticipate that a larger adoption of these new technologies by the neuroscience community will drive a new era of experimental opportunities in the study of axon physiology and consequently, neuronal function.

Cheese-related listeriosis outbreak, Portugal, March 2009 to February 2012.

In Portugal, listeriosis has been notifiable since April 2014, but there is no active surveillance programme for the disease. A retrospective study involving 25 national hospitals led to the detection of an outbreak that occurred between March 2009 and February 2012. The amount of time between the start of the outbreak and its detection was 16 months. Of the 30 cases of listeriosis reported, 27 were in the Lisbon and Vale do Tejo region. Two cases were maternal/neonatal infections and one resulted in fetal loss. The mean age of the non-maternal/neonatal cases was 59 years (standard deviation: 17); 13 cases were more than 65 years old. The case fatality rate was 36.7%. All cases were caused by molecular serogroup IVb isolates indistinguishable by pulsed-field gel electrophoresis and ribotype profiles. Collaborative investigations with the national health and food safety authorities identified cheese as the probable source of infection, traced to a processing plant. The magnitude of this outbreak, the first reported food-borne listeriosis outbreak in Portugal, highlights the importance of having an effective listeriosis surveillance system in place for early detection and resolution of outbreaks, as well as the need for a process for the prompt submission of Listeria monocytogenes isolates for routine laboratory typing.

Mild to moderate increases in activity are associated with increased seizure incidence in dogs with idiopathic epilepsy receiving anti-epileptic drugs.

OBJECTIVE: Epilepsy is a chronic disorder, and approximately 25% to 30% of dogs with epilepsy are refractory to anti-epileptic drugs. As increased activity has been shown to reduce seizure frequency in people with epilepsy, the goal of this study was to evaluate the relationship between deviation from baseline activity and seizure incidence in dogs with epilepsy. MATERIALS AND METHODS: Activity and seizure data were obtained using a canine activity monitoring device and owner observed seizure logs in 53 dogs with idiopathic epilepsy receiving anti-epileptic drugs. Each dog's activity was individually measured, and 14-day baseline averages were calculated. Logistic regression was performed to evaluate how an observed increase in activity, ranging from 0% to 50%, above baseline activity, affects the incidence of a seizure in the following 24 hours. RESULTS: A total of 8540 activity days and 365 seizure days were used in the final analysis with an average of 11 seizures per dog (range 0 to 30 seizures). Seizure incidence was significantly more likely when activity was 10%, 20%, or 30% above baseline activity in the 24 hours before the day of a documented seizure [95% confidence interval (1.02 to 1.60), P=0.033; 95% confidence interval (1.08 to 1.80), P=0.010; 95% confidence interval (1.13 to 2.07), P=0.005, respectively]. However, when activity levels were 40% and 50% above baseline, the effect diminished (95% confidence interval (0.74 to 1.70), P=0.532; or 95% confidence interval (0.56 to 1.66), P=0.988, respectively). CLINICAL SIGNIFICANCE: Differently than in humans, this study demonstrated that a mild to moderate increase in activity resulted in a higher seizure incidence within 24 hours in dogs with epilepsy.

Bidirectional flow of action potentials in axons drives activity dynamics in neuronal cultures.

Objective. Recent technological advances are revealing the complex physiology of the axon and challenging long-standing assumptions. Namely, while most action potential (AP) initiation occurs at the axon initial segment in central nervous system neurons, initiation in distal parts of the axon has been reported to occur in both physiological and pathological conditions. The functional role of these ectopic APs, if exists, is still not clear, nor its impact on network activity dynamics.Approach. Using an electrophysiology platform specifically designed for assessing axonal conduction we show here for the first time regular and effective bidirectional axonal conduction in hippocampal and dorsal root ganglia cultures. We investigate and characterize this bidirectional propagation both in physiological conditions and after distal axotomy.Main results.A significant fraction of APs are not coming from the canonical synapse-dendrite-soma signal flow, but instead from signals originating at the distal axon. Importantly, antidromic APs may carry information and can have a functional impact on the neuron, as they consistently depolarize the soma. Thus, plasticity or gene transduction mechanisms triggered by soma depolarization can also be affected by these antidromic APs. Conduction velocity is asymmetrical, with antidromic conduction being slower than orthodromic.Significance.Altogether these findings have important implications for the study of neuronal functionin vitro, reshaping our understanding on how information flows in neuronal cultures.

Neurophysiological, behavioral and morphological abnormalities in the Fabry knockout mice.

Fabry disease (OMIM 301500) is a rare X-linked recessive disorder caused by mutations in the alpha-galactosidase gene (GLA). Loss of alpha-galactosidase (alpha-Gal) activity leads to the abnormal accumulation of glycosphingolipids in lysosomes predominantly of vascular endothelial cells. Clinically the disorder presents with angiokeratomas, clouding of the cornea, and renal, cardiac, and cerebrovascular complications. In addition, there is an increased incidence of neuropathic pain in Fabry patients. In this study, we investigated the implications of loss of alpha-galactosidase A activity on sensorimotor function and peripheral nervous system. Similar to the described in Fabry disease patients, the sensorimotor assessment of Fabry mice revealed diminished locomotor activity and warm hypoalgesia as assessed in the hot-plate. Moreover Fabry mice displayed alterations both in balance and co-ordination. By histological analysis, the cyto-architecture of Fabry mice sciatic nerves showed an increase in mean cross-sectional area accompanied by a decrease in the density of non-myelinated fibers as well as a trend for a decreased number of small myelinated fibers, a well established feature of Fabry disease. A relative preservation of large myelinated fibers and nerve conduction velocity measurements was observed. Our findings demonstrate for the first time that Fabry knockout mice have Gb3 accumulation in the peripheral nervous system, alterations in sensorimotor function, hypoalgesia and no impairment of motor nerve conduction.

Induction of short gut syndrome and transplantation in a porcine model.

UNLABELLED: Experimental models in small animals have been described for nutritional studies after small bowel transplantation for extensive resection. Herein, we compared the outcome of transplanted pigs that underwent transplantation after total small bowel resection (SBR) with controls without transplantation. METHODS: Twenty-one Landrace pigs (mean weight 30 kg) were assigned to 1 of 3 groups: group 1 (n = 6) underwent 80% SBR; group 2 (n = 9), total bowel resection; and group 3 (n = 6) total resection plus small bowel transplantation. Postoperative evaluation included biochemical analyses, weights, and evaluation of clinical status. Conventional endoscopies with graft biopsies were obtained every 4 days to assess rejection. RESULTS: Group 1 showed increased body weight after 3 weeks due to bowel adaptation, whereas groups 2 and 3 lost weight, an observation that correlated with biochemical analyses. Median survival in group 3 was 10 +/- 2 days; all hosts died of sepsis related to severe acute rejection. DISCUSSION: Short gut syndrome appeared in group 2 but not in group 1, where intestinal adaptation was observed by 4 weeks after the resection. Rejection was confirmed in group 3 using conventional endoscopy plus biopsies and at necropsy. CONCLUSION: Total bowel resection is an adequate model for short gut syndrome in pigs, rejection can be readily identified by using conventional endoscopy.

Familial amyloid polyneuropathy: receptor for advanced glycation end products-dependent triggering of neuronal inflammatory and apoptotic pathways.

Familial amyloid polyneuropathy (FAP) is a neurodegenerative disorder associated with extracellular deposition of mutant transthyretin (TTR) amyloid fibrils, particularly in the peripheral nervous system. We have hypothesized that binding of TTR fibrils to the receptor for advanced glycation end products (RAGE) on critical cellular targets is associated with a destructive stress response underlying peripheral nerve dysfunction. Analysis of nerve biopsy samples from patients with FAP (n = 16) at different stages of disease (0-3), compared with age-matched controls (n = 4), by semiquantitative immunohistology and in situ hybridization showed increased levels of RAGE, beginning at the earliest stages of the disease (FAP 0; p < 0.02) and especially localized in axons. Upregulation of proinflammatory cytokines (tumor necrosis factor-alpha and interleukin-1beta) (approximately threefold; p < 0.02) and the inducible form of nitric oxide synthase (iNOS) ( approximately 2.5-fold; p < 0.04) was also observed in a distribution overlapping RAGE expression. Tyrosine nitration and increased activated caspase-3 in axons from FAP patients (p < 0.03) were apparent. Although these data suggest the presence of ongoing neuronal stress, there was no upregulation of neurotrophins (nerve growth factor and neurotrophin-3) in FAP nerves. Studies on cultured neuronal-like, Schwann, and endothelial cells incubated with TTR fibrils displayed RAGE-dependent expression of cytokines and iNOS at early times (6 and 12 hr, respectively), followed by later (24 hr) activation of caspase-3 and DNA fragmentation. We propose that the interaction of TTR fibrils with RAGE may contribute to cellular stress and toxicity in FAP. Furthermore, there is an apparent lack of responsiveness of Schwann cells in FAP nerve to provide neurotrophic factors.

Videolaparocholecystectomy: casuistry of 1000 cases.

Despite the ongoing evolution in the medical treatment of biliary pathology, the standard of treatment for gallstones remains cholecystectomy. There are no alternative treatments that have shown the same efficacy as surgery. Current alternative treatments have shown high recurrence and failure rates. Cholecystectomy remains the gold standard for management of gallstones. The surgical access of laparoscopic cholecystectomy accomplished by Mouret in 1987 allows for a reduction in operative trauma, hospital stay, postoperative pain and convalescence. These factors permit a faster return to normal activities. Today, laparoscopic cholecystectomy is performed in almost all medical centers around the world; however, the procedure is not free of complications. The objective of this study was to analyze our first 1000 cases of laparoscopic cholecystectomy, giving emphasis to the morbidity and mortality of the procedure.

Videolaparoscopic approach of the splenic cyst: a case report.

The authors report a case of an asymptomatic 30-year-old female patient with an extensive cystic lesion continuous with the splenic parenchyma. A review of the literature and use of a videolaparoscopic approach to the treatment of these lesions is presented.

Laparoscopic versus open appendicectomy: a comparative study.

There are many questions regarding the advantages and disadvantages a videolaparoscopic approach in the treatment of acute appendicitis. The authors present the results of a non-randomized, prospective study with 496 patients admitted between January 1992 and March 1998 by the General Surgery Service of São Rafael Hospital Salvador-BA-Brazil. The patients were submitted for appendicectomy by video laparoscopy or by the traditional open method, and variables such as surgery duration, morbidity, mortality, costs, and length of stay (LOS) were compared. The results demonstrate that laparoscopic appendicectomy is a safe alternative for treatment of acute appendicitis; however, there are several disadvantages that gradually must be overcome.

Acute cholecystitis: video-laparoscopic versus traditional treatment.

It has been shown that a video-laparoscopic approach is the preferred method for treatment of cholecystitis. However, when we consider acute cholecystitis, many questions must be answered. The aim of this study is to compare video-laparoscopic and conventional surgery in the management of acute cholecystitis.

Non-traumatic acute abdomen: videolaparoscopic approach.

BACKGROUND AND OBJECTIVE: Although videolaparoscopy has been considered a safe method for many elective procedures, its use in traumatic and non-traumatic acute abdomen needs to be evaluated. The aim of this article is to evaluate the role of videolaparoscopy in non-traumatic acute abdomen as a method of diagnosis and treatment. METHODS: Between January 1992 and December 1996, 462 patients' charts were reviewed, retrospectively. Patients were admitted to the emergency room of São Rafael Hospital with symptoms of non-traumatic acute abdomen. Routine investigation of abdominal pain was performed in all patients, followed by videolaparoscopy. The laparoscopic procedures were done with four main purposes: diagnosis (ie, enteritis); diagnosis and treatment (ie, appendicitis); treatment only, when the diagnosis was known (ie, acute cholecystitis); and in cases where the conversion to conventional laparotomy was necessary, indicating the best incision. RESULTS: The vast majority of patients had inflammatory causes of acute abdomen (82.03%); others causes were hemoperitoneum (11.03%), bowel obstruction (3.25%), perforation of a hollow viscera (1.74%), vascular occlusion (1.3%), and negative laparoscopy (0.65%). CONCLUSIONS: This study shows that laparotomy was necessary in only 7.14% of the patients. The videolaparoscopic approach was used for diagnosis (99.35%) and treatment (92.86%) of patients with acute abdomen.

Studies of antithyroid antibodies in Down's syndrome.

The presence of antithyroid antibodies (antithyroglobulin and antimicrosomal) in serum of patients with Down's syndrome and their respective mothers were studied based on data from the literature, showing a possible correlation between the presence of these antibodies in the serum of mothers and the birth of mongoloid children. Antithyroid antibodies were studied in 40 patients with Down's syndrome, with ages ranging from 5 months to 21 years old, 24 males and 16 females and in the respective mothers whose ages varied from 22 to 66 years. In none of the analyzed sera of the mongoloids as well of their mothers, the authors were able to detect the antithyroid antibodies studied.

[Is it necessary to operate on asymptomatic aneurysms? Apropos of 114 surgically treated asymptomatic aneurysms]. / Faut-il opérer les anévrysmes asymptomatiques? A propos de 114 anévrysmes asymptomatiques opérés.

A six years retrospective analysis of asymptomatic aneurysms (A.A.) was done in 4 neurosurgical departments: 114 AA were clipped in 99 patients. In 44 patients (48 asymptomatic aneurysms) the surgical procedure was achieved in one step for both symptomatic and asymptomatic aneurysms. In 59 patients (66 asymptomatic aneurysms) the surgical procedure was delayed as it necessitated a second and elective craniotomy. As regard the treatment of asymptomatic aneurysms, there was no morbidity, and one death due to a massive pulmonary embolism. These surgical results are undoubtebly better than the risk of hemorrhage from unruptured aneurysm as emphasized in the literature.

Fish assemblage in a semi-arid Neotropical reservoir: composition, structure and patterns of diversity and abundance.

The aim of this study was to analyse the composition, structure and spatial and temporal patterns of diversity and abundance of the ichthyofauna of the Santa Cruz Reservoir in semi-arid Brazil. Data were collected quarterly at eight sampling locations on the reservoir between February 2010 and November 2011 using gillnets from 12- to 70-mm mesh that were left in the water for 12h00min during the night. We evaluated the composition, structure and assemblage descriptors (Shannon-Wiener diversity index and equitability, respectively) and catch per unit effort by the number (CPUEn) and biomass (CPUEb) of the ichthyofauna. The 6,047 individuals (399,211.6 g) captured represented three orders, ten families and 20 species, of which four belonged to introduced species. The family Characidae was the most abundant with a total of 2,772 (45.8%) individuals captured. The species-abundance curve fit the log-normal model. In the spatial analysis of diversity, there were significant differences between sampling sites in the lacustrine and fluvial regions, and the highest values were found in the lacustrine region. In the temporal analysis of diversity, significant differences were also observed between the rainy and dry seasons, and the higher values were found during the dry season. Equitability followed the same spatiotemporal pattern as diversity. The Spearman correlation was significantly negative between diversity and rainfall. A cluster analysis spatially separated the ichthyofauna into two groups: one group formed by sampling sites in the fluvial region and another group formed by the remainder of the points in the lacustrine region. Both the CPUEn and CPUEb values were higher at point 8 (fluvial region) and during the rainy season. A two-way ANOVA showed that the CPUEn and CPUEb values were spatially and temporally significant. We conclude that the spatial and temporal trends of diversity in the Santa Cruz reservoir differ from those of other Brazilian reservoirs but that the fish community composition and spatiotemporal patterns of abundance were similar.

Performance and parasite control of different genetic groups of lambs finished in irrigated pasture / Desempenho e controle parasitário de diferentes grupos genéticos de cordeiros terminados em pastagem irrigada

The aim of this study was to compare the following four genetic groups of hair sheep: Santa Inês (SI), Morada Nova (MN), Brazilian Somali (BS), and the F1 1/2Dorper x 1/2Morada Nova crossbreed on traits related to growth and parasitic infection. Thirty-three male lambs of the same age and of simple birth, under the same pre-weaning management conditions were used in the experiment. After weaning the animals were housed in a completely randomized design in paddocks made of Panicum maximum cv. Tanzania. Along the course of the research, the performance of the four groups of sheep was observed to be negatively affected by gastrointestinal parasites, but there was a genotype effect to the average daily weight gain (ADWG), where the SI and F1 genotypes presented higher values. The effects of genotype, time and genotype x time interaction were significant in weight and corporal score (CS) measurements. The BS lambs had the highest CS values throughout the experiment despite not presenting greater weight gain when compared to the SI and F1 breeds. There were also significant effects of time and genotype x time interaction for packed cell volume (PCV) and FAMACHA© score (FAM) and only the time effect was significant in the total number of eggs per gram (EPG) and total plasma protein (TPP). The MN lambs showed higher PCV values and unlike the other groups, presented a FAMACHA© score below 3 and PCV above 23% even having a higher EPG tendency, especially in the initial phase, indicating a possible higher resilience to infection caused by gastrointestinal parasites.

O objetivo deste estudo foi comparar quatro grupos genéticos de ovinos: Santa Inês (SI), Somalis Brasileira (SB), Morada Nova (MN) e 1/2 Dorper - 1/2 Morada Nova (F1) quanto às características de crescimento e de infecção parasitária. Trinta e três cordeiros machos, de mesma idade, nascidos de parto simples e submetidos às mesmas condições de manejo pré-desmame foram utilizados no experimento. Após o desmame, os animais foram alojados em piquetes de capim Panicum maximum cv. Tanzânia, em um sistema rotativo de pastejo sob um delineamento inteiramente ao acaso. Os resultados mostraram que, ao longo do experimento, o desempenho ponderal dos quatro grupos genéticos foi negativamente afetado pela infecção por endoparasitas, mas o efeito de genótipo foi significativo para ganho de peso médio diário, e os grupos SI e F1 apresentaram melhores médias. O efeito do genótipo, tempo e interação genótipo x tempo foi significativo para o peso e o escore corporal. Os cordeiros da raça SB apresentaram maiores escores corporais ao longo do experimento, apesar do menor ganho de peso quando comparados aos dos grupos SI e F1. Houve efeito significativo do tempo e da interação genótipo x tempo para o hematócrito e para o grau FAMACHA©. Somente efeito do tempo foi verificado para as características OPG e proteína plasmática total. Os cordeiros da raça Morada Nova, ao contrário dos demais grupos, mantiveram o grau FAMACHA© inferior a 3 e hematócrito inferior a 23%, mesmo com tendência de maior OPG, principalmente na fase inicial, indicando uma possível maior capacidade de adaptação à infecção por endoparasitas.

Activation of ERK1/2 MAP kinases in familial amyloidotic polyneuropathy.

Familial amyloidotic polyneuropathy (FAP) is a neurodegenerative disorder characterized by the extracellular deposition of transthyretin (TTR), especially in the PNS. Given the invasiveness of nerve biopsy, salivary glands (SG) from FAP patients were used previously in microarray analysis; mitogen-activated protein (MAP) kinase phosphatase 1 (MKP-1) was down-regulated in FAP. Results were validated by RT-PCR and immunohistochemistry both in SG and in nerve biopsies of different stages of disease progression. MKP-3 was also down-regulated in FAP SG biopsies. Given the relationship between MKPs and MAPKs, the latter were investigated. Only extracellular signal-regulated kinases 1/2 (ERK1/2) displayed increased activation in FAP SG and nerves. ERK1/2 kinase (MEK1/2) activation was also up-regulated in FAP nerves. In addition, an FAP transgenic mouse model revealed increased ERK1/2 activation in peripheral nerve affected with TTR deposition when compared to control animals. Cultured rat Schwannoma cell line treatment with TTR aggregates stimulated ERK1/2 activation, which was partially mediated by the receptor for advanced glycation end-products (RAGE). Moreover, caspase-3 activation triggered by TTR aggregates was abrogated by U0126, a MEK1/2 inhibitor, indicating that ERK1/2 activation is essential for TTR aggregates-induced cytotoxicity. Taken together, these data suggest that abnormally sustained activation of ERK in FAP may represent an early signaling cascade leading to neurodegeneration.