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1.
Proc Biol Sci ; 290(2010): 20230957, 2023 Nov 08.
Article in English | MEDLINE | ID: mdl-37909073

ABSTRACT

Recent studies have suggested the presence of moonlight mediated behaviour in avian aerial insectivores, such as swifts. Here, we use the combined analysis of state-of-the-art activity logger data across three swift species, the common, pallid and alpine swifts, to quantify flight height and activity in responses to moonlight-driven crepuscular and nocturnal light conditions. Our results show a significant response in flight heights to moonlight illuminance for common and pallid swifts, i.e. when moon illuminance increased flight height also increased, while a moonlight-driven response is absent in alpine swifts. We show a weak relationship between night-time illuminance-driven responses and twilight ascending behaviour, suggesting a decoupling of both crepuscular and night-time behaviour. We suggest that swifts optimize their flight behaviour to adapt to favourable night-time light conditions, driven by light-responsive and size-dependent vertical insect stratification and weather conditions.


Subject(s)
Birds , Flight, Animal , Animals , Flight, Animal/physiology , Birds/physiology , Insecta
2.
Proc Natl Acad Sci U S A ; 117(47): 29795-29802, 2020 11 24.
Article in English | MEDLINE | ID: mdl-33158970

ABSTRACT

Meningococcal meningitis remains a substantial cause of mortality and morbidity worldwide. Until recently, countries in the African meningitis belt were susceptible to devastating outbreaks, largely attributed to serogroup A Neisseria meningitidis (MenA). Vaccination with glycoconjugates of MenA capsular polysaccharide led to an almost complete elimination of MenA clinical cases. To understand the molecular basis of vaccine-induced protection, we generated a panel of oligosaccharide fragments of different lengths and tested them with polyclonal and monoclonal antibodies by inhibition enzyme-linked immunosorbent assay, surface plasmon resonance, and competitive human serum bactericidal assay, which is a surrogate for protection. The epitope was shown to optimize between three and six repeating units and to be O-acetylated. The molecular interactions between a protective monoclonal antibody and a MenA capsular polysaccharide fragment were further elucidated at the atomic level by saturation transfer difference NMR spectroscopy and X-ray crystallography. The epitope consists of a trisaccharide anchored to the antibody via the O- and N-acetyl moieties through either H-bonding or CH-π interactions. In silico docking showed that 3-O-acetylation of the upstream residue is essential for antibody binding, while O-acetate could be equally accommodated at three and four positions of the other two residues. These results shed light on the mechanism of action of current MenA vaccines and provide a foundation for the rational design of improved therapies.


Subject(s)
Epitopes/immunology , Meningitis, Meningococcal/prevention & control , Meningococcal Vaccines/immunology , Neisseria meningitidis/immunology , Polysaccharides, Bacterial/immunology , Acetylation , Adolescent , Antibodies, Bacterial/chemistry , Antibodies, Bacterial/immunology , Child , Clinical Trials, Phase II as Topic , Crystallography, X-Ray , Female , Humans , Immunogenicity, Vaccine , Immunoglobulin Fab Fragments/chemistry , Immunoglobulin Fab Fragments/immunology , Male , Meningitis, Meningococcal/immunology , Meningitis, Meningococcal/microbiology , Meningococcal Vaccines/therapeutic use , Molecular Docking Simulation , Multicenter Studies as Topic , Polysaccharides, Bacterial/chemistry , Randomized Controlled Trials as Topic , Serogroup , Serum Bactericidal Antibody Assay , Vaccines, Conjugate/immunology , Vaccines, Conjugate/therapeutic use
3.
Sensors (Basel) ; 22(19)2022 Oct 07.
Article in English | MEDLINE | ID: mdl-36236708

ABSTRACT

The progressive loss of functional capacity due to aging is a serious problem that can compromise human locomotion capacity, requiring the help of an assistant and reducing independence. The NanoStim project aims to develop a system capable of performing treatment with electrostimulation at the patient's home, reducing the number of consultations. The knee angle is one of the essential attributes in this context, helping understand the patient's movement during the treatment session. This article presents a wearable system that recognizes the knee angle through IMU sensors. The hardware chosen for the wearables are low cost, including an ESP32 microcontroller and an MPU-6050 sensor. However, this hardware impairs signal accuracy in the multitasking environment expected in rehabilitation treatment. Three optimization filters with algorithmic complexity O(1) were tested to improve the signal's noise. The complementary filter obtained the best result, presenting an average error of 0.6 degrees and an improvement of 77% in MSE. Furthermore, an interface in the mobile app was developed to respond immediately to the recognized movement. The systems were tested with volunteers in a real environment and could successfully measure the movement performed. In the future, it is planned to use the recognized angle with the electromyography sensor.


Subject(s)
Wearable Electronic Devices , Biomechanical Phenomena , Humans , Knee , Knee Joint/physiology , Muscles
4.
Int Ophthalmol ; 42(4): 1175-1182, 2022 Apr.
Article in English | MEDLINE | ID: mdl-34761336

ABSTRACT

PURPOSE: To describe a technique for cataract surgery in eyes with small pupils that combines the use of the femtosecond laser and an iris expansion device, but without the use of corneal sutures and an ophthalmic viscosurgical device (OVD) at the time of laser application. METHODS: A retrospective case series of three eyes with small pupils were operated by the same surgeon without a corneal suture and with removal of anterior chamber OVD prior to laser application. RESULTS: Corrected distance visual acuity (CDVA) for 1 eye in a 70 year-old patient was 20/70 preoperatively and 20/20 thirty days postoperatively. CDVA for a second patient was 20/50 and 20/200 in the two eyes, which improved to 20/25 two months postoperatively in both eyes. There were no complications observed and the intraocular lens were well-centered. CONCLUSION: The use of mechanical pupil expander rings is safe and practical in setting small pupils during femtosecond laser-assisted cataract surgery.


Subject(s)
Cataract Extraction , Cataract , Laser Therapy , Phacoemulsification , Aged , Cataract/complications , Cataract Extraction/methods , Humans , Laser Therapy/methods , Lasers , Lens Implantation, Intraocular , Miosis , Phacoemulsification/methods , Pupil , Retrospective Studies , Sutures
5.
Chemistry ; 26(31): 6944, 2020 Jun 02.
Article in English | MEDLINE | ID: mdl-32390224

ABSTRACT

Invited for the cover of this issue is the group of Roberto Adamo at GlaxoSmithKline Research Center, Siena, and colleagues at The University of the Basque Country and Basque Research Technology Alliance. The image depicts a tactical plan with the different elements of the research as part of the team. Read the full text of the article at 10.1002/chem.202000284.


Subject(s)
Polysaccharides/chemical synthesis , Streptococcus/chemistry , Humans , Polysaccharides/chemistry , Vaccines, Synthetic
6.
Chemistry ; 26(31): 7018-7025, 2020 Jun 02.
Article in English | MEDLINE | ID: mdl-32058627

ABSTRACT

Identification of glycan functional epitopes is of paramount importance for rational design of glycoconjugate vaccines. We recently mapped the structural epitope of the capsular polysaccharide from type III Group B Streptococcus (GBSIII), a major cause of invasive disease in newborns, by using a dimer fragment (composed of two pentasaccharide repeating units) obtained by depolymerization complexed with a protective mAb. Although reported data had suggested a highly complex epitope contained in a helical structure composed of more than four repeating units, we showed that such dimer conjugated to a carrier protein with a proper glycosylation degree elicited functional antibodies comparably to the full-length conjugated polysaccharide. Here, starting from the X-ray crystallographic structure of the polysaccharide fragment-mAb complex, we synthesized a hexasaccharide comprising exclusively the relevant positions involved in binding. Combining competitive surface plasmon resonance and saturation transfer difference NMR spectroscopy as well as in-silico modeling, we demonstrated that this synthetic glycan was recognized by the mAb similarly to the dimer. The hexasaccharide conjugated to CRM197 , a mutant of diphtheria toxin, elicited a robust functional immune response that was not inferior to the polysaccharide conjugate, indicating that it may suffice as a vaccine antigen. This is the first evidence of an X-ray crystallography-guided design of a synthetic carbohydrate-based conjugate vaccine.


Subject(s)
Bacterial Proteins/chemistry , Bacterial Proteins/immunology , Epitopes/chemistry , Glycoconjugates/chemistry , Polysaccharides/immunology , Streptococcus agalactiae/chemistry , Streptococcus agalactiae/immunology , Vaccines, Conjugate/chemistry , Vaccines, Conjugate/immunology , Humans , Vaccines, Synthetic
7.
Science ; 384(6695): 573-579, 2024 May 03.
Article in English | MEDLINE | ID: mdl-38696577

ABSTRACT

Neurons on the left and right sides of the nervous system often show asymmetric properties, but how such differences arise is poorly understood. Genetic screening in zebrafish revealed that loss of function of the transmembrane protein Cachd1 resulted in right-sided habenula neurons adopting left-sided identity. Cachd1 is expressed in neuronal progenitors, functions downstream of asymmetric environmental signals, and influences timing of the normally asymmetric patterns of neurogenesis. Biochemical and structural analyses demonstrated that Cachd1 can bind simultaneously to Lrp6 and Frizzled family Wnt co-receptors. Consistent with this, lrp6 mutant zebrafish lose asymmetry in the habenulae, and epistasis experiments support a role for Cachd1 in modulating Wnt pathway activity in the brain. These studies identify Cachd1 as a conserved Wnt receptor-interacting protein that regulates lateralized neuronal identity in the zebrafish brain.


Subject(s)
Calcium Channels , Habenula , Neurogenesis , Neurons , Wnt Signaling Pathway , Zebrafish Proteins , Zebrafish , Animals , Frizzled Receptors/metabolism , Frizzled Receptors/genetics , Habenula/metabolism , Habenula/embryology , Loss of Function Mutation , Low Density Lipoprotein Receptor-Related Protein-6/metabolism , Low Density Lipoprotein Receptor-Related Protein-6/genetics , Membrane Proteins/metabolism , Membrane Proteins/genetics , Neurons/metabolism , Receptors, Wnt/metabolism , Receptors, Wnt/genetics , Zebrafish/embryology , Zebrafish/genetics , Zebrafish Proteins/metabolism , Zebrafish Proteins/genetics , Calcium Channels/genetics , Calcium Channels/metabolism
8.
Scand J Gastroenterol ; 48(6): 712-8, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23534461

ABSTRACT

BACKGROUND: The relation between alcoholic liver disease (ALD) and iron overload is well known. Liver biopsy is the gold standard for assessing iron stores. MRI is also validated for liver iron concentration (LIC) assessment. We aimed to assess the effect of active drinking in liver iron stores and the practicability of measuring LIC by MRI in ALD patients. MATERIALS AND METHODS: We measured LIC by MRI in 58 ALD patients. We divided patients into two groups - with and without active alcoholism - and we compared several variables between them. We evaluated MRI-LIC, liver iron stores grade, ferritin and necroinflammatory activity grade for significant correlations. RESULTS: Significant necroinflammation (40.0% vs. 4.3%), LIC (40.1 vs. 24.3 µmol/g), and ferritin (1259.7 vs. 568.7 pmol/L) were significantly higher in drinkers. LIC values had a strong association with iron stores grade (r s = 0.706). Ferritin correlated with LIC (r s = 0.615), iron stores grade (r s = 0.546), and necroinflammation (r s = 0.313). The odds ratio for elevated serum ferritin when actively drinking was 7.32. CONCLUSION: Active alcoholism is associated with increased ALD activity. It is also the key factor in iron overload. Scheuers' semiquantitative score with Perls' staining gives a fairly accurate picture of liver iron overload. Serum ferritin also shows a good correlation with LIC values and biopsy iron stores grade. As most patients present only with mild iron overload, serum ferritin measurement and semiquantitative evaluation of iron stores are adequate, considering MRI high cost. However, if MRI is required to evaluate liver structure, LIC assessment could be performed without added cost.


Subject(s)
Alcoholism/metabolism , Ferritins/metabolism , Hepatitis, Alcoholic/metabolism , Hepatitis, Alcoholic/pathology , Iron/metabolism , Magnetic Resonance Imaging , Adult , Aged , Alcoholism/complications , Biopsy , Female , Ferritins/blood , Humans , Iron Overload/blood , Iron Overload/etiology , Male , Middle Aged
9.
Carbohydr Polym ; 311: 120736, 2023 Jul 01.
Article in English | MEDLINE | ID: mdl-37028871

ABSTRACT

Group A Carbohydrate (GAC), conjugated to an appropriate carrier protein, has been proposed as an attractive vaccine candidate against Group A Streptococcus infections. Native GAC consists of a polyrhamnose (polyRha) backbone with N-acetylglucosamine (GlcNAc) at every second rhamnose residue. Both native GAC and the polyRha backbone have been proposed as vaccine components. Here, chemical synthesis and glycoengineering were used to generate a panel of different length GAC and polyrhamnose fragments. Biochemical analyses were performed confirming that the epitope motif of GAC is composed of GlcNAc in the context of the polyrhamnose backbone. Conjugates from GAC isolated and purified from a bacterial strain and polyRha genetically expressed in E. coli and with similar molecular size to GAC were compared in different animal models. The GAC conjugate elicited higher anti-GAC IgG levels with stronger binding capacity to Group A Streptococcus strains than the polyRha one, both in mice and in rabbits. This work contributes to the development of a vaccine against Group A Streptococcus suggesting GAC as preferable saccharide antigen to include in the vaccine.


Subject(s)
Acetylglucosamine , Vaccines , Mice , Animals , Rabbits , Acetylglucosamine/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism , Carbohydrates , Streptococcus pyogenes/metabolism , Glycoconjugates/metabolism
10.
Front Neuroanat ; 16: 840924, 2022.
Article in English | MEDLINE | ID: mdl-35721460

ABSTRACT

Zebrafish telencephalon acquires an everted morphology by a two-step process that occurs from 1 to 5 days post-fertilization (dpf). Little is known about how this process affects the positioning of discrete telencephalic cell populations, hindering our understanding of how eversion impacts telencephalic structural organization. In this study, we characterize the neurochemistry, cycle state and morphology of an EGFP positive (+) cell population in the telencephalon of Et(gata2:EGFP)bi105 transgenic fish during eversion and up to 20dpf. We map the transgene insertion to the early-growth-response-gene-3 (egr3) locus and show that EGFP expression recapitulates endogenous egr3 expression throughout much of the pallial telencephalon. Using the gata2:EGFP bi105 transgene, in combination with other well-characterized transgenes and structural markers, we track the development of various cell populations in the zebrafish telencephalon as it undergoes the morphological changes underlying eversion. These datasets were registered to reference brains to form an atlas of telencephalic development at key stages of the eversion process (1dpf, 2dpf, and 5dpf) and compared to expression in adulthood. Finally, we registered gata2:EGFPbi105 expression to the Zebrafish Brain Browser 6dpf reference brain (ZBB, see Marquart et al., 2015, 2017; Tabor et al., 2019), to allow comparison of this expression pattern with anatomical data already in ZBB.

11.
Article in English | MEDLINE | ID: mdl-36612545

ABSTRACT

Birds are potential carriers of pathogens affecting humans and agriculture. Aiming to evaluate the occurrence of the top three most important foodborne pathogens in free-living birds in Portugal, we investigated 108 individual fecal samples from free-living birds and one pooled sample of gull feces (n = 50) for the presence of Escherichia coli (pathogenic and non-pathogenic), Salmonella spp. and Campylobacter spp. Virulence- and antimicrobial resistance- (AMR) associated genes were detected by PCR and Whole-Genome Sequencing (WGS), and phenotypic (serotyping and AMR profiles) characterization was performed. Overall, 8.9% of samples tested positive for pathogenic E. coli, 2.8% for Salmonella spp., and 9.9% for Campylobacter spp. AMR was performed on all pathogenic isolates and in a fraction of non-pathogenic E. coli, being detected in 25.9% of them. Ten of the tested E. coli isolates were multidrug-resistant (MDR), and seven of them were Extended-spectrum ß-lactamase (ESBL) producers. Among Salmonella (n = 3) and Campylobacter (n = 9), only one strain of C. jejuni was identified as MDR. Most of the identified serotypes/sequence types had already been found to be associated with human disease. These results show that free-living birds in Portugal may act as carriers of foodborne pathogens linked to human disease, some of them resistant to critically important antimicrobials.


Subject(s)
Anti-Infective Agents , Campylobacter , Animals , Humans , Escherichia coli/genetics , Portugal/epidemiology , Campylobacter/genetics , Birds , Salmonella/genetics , Anti-Bacterial Agents/pharmacology
12.
Animals (Basel) ; 12(23)2022 Nov 25.
Article in English | MEDLINE | ID: mdl-36496804

ABSTRACT

Coronaviruses (CoVs) are part of the Coronaviridae family, and the genera Gamma (γ) and Delta (δ) are found mostly in birds. Migratory birds have an enormous potential for dispersing pathogenic microorganisms. Ducks (order Anseriformes) can host CoVs from birds, with pathogenic expression and high economic impact. This study aimed to identify and characterize the diversity of CoVs in migratory ducks from Portugal. Duck stool samples were collected using cloacal swabs from 72 individuals (Anas platyrhynchos, Anas acuta, and Anas crecca). Among the 72 samples tested, 24 showed amplicons of the expected size. Twenty-three were characterized as Gammacoronavirus and one as Deltacoronavirus (accession numbers ON368935-ON368954; ON721380-ON721383). The Gammacoronaviruses sequences showed greater similarities to those obtained in ducks (Anas platyrhynchos) from Finland and Poland, Anas crecca duck from the USA, and mute swans from Poland. Birds can occupy many habitats and therefore play diverse ecological roles in various ecosystems, especially given their ability to migrate exceptional distances, facilitating the dispersal of microorganisms with animal and/or human impact. There are a considerable number of studies that have detected CoVs in ducks, but none in Portugal. The present study assessed the circulation of CoVs in wild ducks from Portugal, being the first description of CoVs for these animals in Portugal.

13.
JBI Evid Implement ; 20(S1): S76-S87, 2022 08 01.
Article in English | MEDLINE | ID: mdl-36372796

ABSTRACT

OBJECTIVES: To implement evidence-based practice related to care and flushing of nasogastric tubes inserted for feeding, in a general medicine ward. INTRODUCTION: Nasogastric tube feeding is a widely used nutritional support form. Although performed by qualified professionals, it is not a harm-free intervention. Progression to the trachea during initial insertion, aspiration of gastric contents, improper position for patient feeding, and/or a blocked tube are examples of problems that can occur. METHODS: The project used JBI's methodological approach of the Clinical Evidence System and Getting Research into Practice audit and feedback tool. A baseline audit focused on nursing procedures related to the maintenance of nasogastric tube feeding, based on 14 criteria informed by the JBI evidence summaries, was performed for a month. Education sessions and other engagement strategies and resources were used to increase nasogastric tube maintenance. This best-practice implementation was conducted in Portugal, between January 2020 and April 2021, in a 33-bed general medicine ward with a staff of 30 registered nurses. RESULTS: Different samples, for each audited procedure, were obtained from a universe of 25 nurses and 14 episodes of patients with nasogastric tube in baseline and 10 in follow-up audit. At baseline, compliance with the criteria ranged from 0 to 88%. Ten of the 14 criteria were below 50%. The follow-up audit showed significant improvement in all compliance criteria (ranging from 44.4 to 100%). Criteria 1 and 2, which were aimed at preventing adverse consequences related to wrong placement or displacement of the nasogastric tube, showed a high postimplementation compliance level (89.3 and 90%). CONCLUSION: With an integrated plan incorporating interventions, strategies, and resources, tailored for this context, we improved nurses' knowledge of nasogastric tube maintenance and achieved significantly increased compliance with nasogastric tube care best-practice. We suggest maintaining current strategies, and reinforcing clinical supervision and regular assessment.


Subject(s)
Clinical Competence , Intubation, Gastrointestinal , Humans , Portugal , Evidence-Based Practice
14.
J Cataract Refract Surg ; 47(2): 265-269, 2021 Feb 01.
Article in English | MEDLINE | ID: mdl-32675655

ABSTRACT

A 29-gauge model test fine needle is used to create a beveled intrascleral tunnel; with microforceps, a 6-0 polypropylene suture is placed in the bore of the needle, which is used as a guide to pass and externalize the monofilament through the sclera. This maneuver is repeated by passing the suture ends through the intraocular lens (IOL) eyelets. The folded IOL is inserted and centered, the sutures are cut, and the flanges are created by thermocautery and inserted into the scleral tunnel. This technique was performed on 7 patients and visual acuity was recorded. The 4-flanged technique for scleral fixation using a 4-eyelet IOL was an effective and a safe treatment in the setting of aphakia.


Subject(s)
Aphakia , Lenses, Intraocular , Aphakia/surgery , Humans , Lens Implantation, Intraocular , Sclera/surgery , Suture Techniques , Sutures
15.
Front Mol Biosci ; 8: 745360, 2021.
Article in English | MEDLINE | ID: mdl-34722634

ABSTRACT

Despite the considerable progress toward the eradication of meningococcal disease with the introduction of glycoconjugate vaccines, previously unremarkable serogroup X has emerged in recent years, recording several outbreaks throughout the African continent. Different serogroup X polysaccharide-based vaccines have been tested in preclinical trials, establishing the principles for further improvement. To elucidate the antigenic determinants of the MenX capsular polysaccharide, we generated a monoclonal antibody, and its bactericidal nature was confirmed using the rabbit serum bactericidal assay. The antibody was tested by the inhibition enzyme-linked immunosorbent assay and surface plasmon resonance against a set of oligosaccharide fragments of different lengths. The epitope was shown to be contained within five to six α-(1-4) phosphodiester mannosamine repeating units. The molecular interactions between the protective monoclonal antibody and the MenX capsular polysaccharide fragment were further detailed at the atomic level by saturation transfer difference nuclear magnetic resonance (NMR) spectroscopy. The NMR results were used for validation of the in silico docking analysis between the X-ray crystal structure of the antibody (Fab fragment) and the modeled hexamer oligosaccharide. The antibody recognizes the MenX fragment by binding all six repeating units of the oligosaccharide via hydrogen bonding, salt bridges, and hydrophobic interactions. In vivo studies demonstrated that conjugates containing five to six repeating units can produce high functional antibody levels. These results provide an insight into the molecular basis of MenX vaccine-induced protection and highlight the requirements for the epitope-based vaccine design.

16.
Rev Port Cardiol ; 29(2): 309-14, 2010 Feb.
Article in English, Portuguese | MEDLINE | ID: mdl-20545255

ABSTRACT

Aortic valve stenosis can be complicated by gastrointestinal bleeding from angiodysplasia. A deficiency of high molecular weight multimers of von Willebrand factor (vWF) (type 2A von Willebrand disease) provides the link between this association, which is known as Heyde syndrome. Aortic valve replacement corrects the vWF abnormalities with long-term resolution of gastrointestinal bleeding. The authors present a case report and a review of this association.


Subject(s)
Angiodysplasia/complications , Aortic Valve Stenosis/complications , Gastrointestinal Hemorrhage/etiology , Aged , Humans , Male , Syndrome
17.
Eur Arch Otorhinolaryngol ; 266(6): 833-8, 2009 Jun.
Article in English | MEDLINE | ID: mdl-18830701

ABSTRACT

The objectives of our study were to characterize nasopharyngeal carcinoma patients in the Portuguese Institute of Oncology Hospital in Lisbon (IPOLFG) and identify the main factors that interfere with patients survival rate. We performed a retrospective study involving 157 patients (65% male and 35% female) between the years 2000 and 2005, and a histological classification according to Health World Organization. We constructed a Kaplan-Meier survival curve for the studied patients and evaluated the significance of the different studied factors with a Pearson correlation study. With an average age of 53 years, most of the carcinomas were type III (58%), followed by type II (30%) and at last type I (8%). Fifty-one of carcinomas were in stage IV at time of diagnosis. Ninety-five patients (60%) had remission. Five-year actuarial survival rate of all patients was 65.1%. There was a significant difference (P = 0.033) in the actuarial survival rate of staged IV patients treated with adjuvant chemotherapy. Undifferentiated nasopharyngeal carcinoma is the most frequent type in our geographic area. Chemotherapy improves survival rate, mainly in late stages.


Subject(s)
Carcinoma/pathology , Carcinoma/therapy , Nasopharyngeal Neoplasms/pathology , Nasopharyngeal Neoplasms/therapy , Adolescent , Adult , Aged , Aged, 80 and over , Carcinoma/epidemiology , Combined Modality Therapy , Female , Humans , Male , Middle Aged , Nasopharyngeal Neoplasms/epidemiology , Neoplasm Staging , Portugal/epidemiology , Retrospective Studies , Survival Rate , Treatment Outcome
18.
Curr Biol ; 29(11): 1771-1786.e5, 2019 06 03.
Article in English | MEDLINE | ID: mdl-31104935

ABSTRACT

Animals must frequently perform a sequence of behaviors to achieve a specific goal. However, the neural mechanisms that promote the continuation and completion of such action sequences are not well understood. Here, we characterize the anatomy, physiology, and function of the nucleus isthmi (NI), a cholinergic nucleus thought to modulate tectal-dependent, goal-directed behaviors. We find that the larval zebrafish NI establishes reciprocal connectivity with the optic tectum and identify two distinct types of isthmic projection neuron that either connect ipsilaterally to retinorecipient laminae of the tectum and pretectum or bilaterally to both tectal hemispheres. Laser ablation of NI caused highly specific deficits in tectally mediated loom-avoidance and prey-catching behavior. In the context of hunting, NI ablation did not affect prey detection or hunting initiation but resulted in larvae failing to sustain prey-tracking sequences and aborting their hunting routines. Moreover, calcium imaging revealed elevated neural activity in NI following onset of hunting behavior. We propose a model in which NI provides state-dependent feedback facilitation to the optic tectum and pretectum to potentiate neural activity and increase the probability of consecutive prey-tracking maneuvers during hunting sequences.


Subject(s)
Efferent Pathways/physiology , Goldfish/physiology , Tectum Mesencephali/physiology , Visual Pathways/physiology , Zebrafish/physiology , Animals , Goldfish/anatomy & histology , Neurons/cytology , Superior Colliculi/anatomy & histology , Superior Colliculi/physiology , Tectum Mesencephali/anatomy & histology , Zebrafish/anatomy & histology
19.
Nat Commun ; 10(1): 5471, 2019 11 29.
Article in English | MEDLINE | ID: mdl-31784529

ABSTRACT

Binocular stereopsis requires the convergence of visual information from corresponding points in visual space seen by two different lines of sight. This may be achieved by superposition of retinal input from each eye onto the same downstream neurons via ipsi- and contralaterally projecting optic nerve fibers. Zebrafish larvae can perceive binocular cues during prey hunting but have exclusively contralateral retinotectal projections. Here we report brain activity in the tectal neuropil ipsilateral to the visually stimulated eye, despite the absence of ipsilateral retinotectal projections. This activity colocalizes with arbors of commissural neurons, termed intertectal neurons (ITNs), that connect the tectal hemispheres. ITNs are GABAergic, establish tectal synapses bilaterally and respond to small moving stimuli. ITN-ablation impairs capture swim initiation when prey is positioned in the binocular strike zone. We propose an intertectal circuit that controls execution of the prey-capture motor program following binocular localization of prey, without requiring ipsilateral retinotectal projections.


Subject(s)
Depth Perception/physiology , GABAergic Neurons/physiology , Motion Perception/physiology , Neuropil/physiology , Predatory Behavior/physiology , Superior Colliculi/physiology , Vision, Binocular/physiology , Visual Pathways/physiology , Animals , Functional Laterality , Larva , Neural Pathways , Neurons , Paramecium , Photic Stimulation , Retinal Ganglion Cells/physiology , Zebrafish
20.
Rev Port Cardiol ; 27(6): 841-9, 2008 Jun.
Article in English, Portuguese | MEDLINE | ID: mdl-18751511

ABSTRACT

Lupus is an inflammatory autoimmune disease that can affect multiple organ systems. As such, it can be diagnosed because of multiorgan or constitutional symptoms, but frequently medical treatment is sought only when there is clinical involvement of a particular organ or system, even if established--but undiagnosed--systemic disease is already present. The authors present the case of a patient admitted to a cardiology unit for acute pericarditis, in whom the diagnosis of systemic lupus erythematosus was made, and highlight the need to consider cardiac involvement in systemic diseases.


Subject(s)
Lupus Erythematosus, Systemic/complications , Pericarditis/etiology , Cardiology , Humans , Lupus Erythematosus, Systemic/diagnosis , Male , Middle Aged
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