Morphological and physiological properties of enhanced green fluorescent protein (EGFP)-expressing wide-field amacrine cells in the ChAT-EGFP mouse line.

Mammalian retinas comprise a variety of interneurons, among which amacrine cells represent the largest group, with more than 30 different cell types each exhibiting a rather distinctive morphology and carrying out a unique function in retinal processing. However, many amacrine types have not been studied systematically because, in particular, amacrine cells with large dendritic fields, i.e. wide-field amacrine cells, have a low abundance and are therefore difficult to target. Here, we used a transgenic mouse line expressing the coding sequence of enhanced green fluorescent protein under the promoter for choline acetyltransferase (ChAT-EGFP mouse) and characterized a single wide-field amacrine cell population monostratifying in layer 2/3 of the inner plexiform layer (WA-S2/3 cell). Somata of WA-S2/3 cells are located either in the inner nuclear layer or are displaced to the ganglion cell layer and exhibit a low cell density. Using immunohistochemistry, we show that WA-S2/3 cells are presumably GABAergic but may also release acetylcholine as their somata are weakly positive for ChAT. Two-photon-guided patch-clamp recordings from intact retinas revealed WA-S2/3 cells to be ON-OFF cells with a homogenous receptive field even larger than the dendritic field. The large spatial extent of the receptive field is most likely due to the extensive homologous and heterologous coupling among WA-S2/3 cells and to other amacrine cells, respectively, as indicated by tracer injections. In summary, we have characterized a novel type of GABAergic ON-OFF wide-field amacrine cell which is ideally suited to providing long-range inhibition to ganglion cells due to its strong coupling.

Inputs underlying the ON-OFF light responses of type 2 wide-field amacrine cells in TH::GFP mice.

In the mammalian retina, two types of catecholaminergic amacrine cells have been described. Although dopaminergic type 1 cells are well characterized, the physiology of type 2 cells is, so far, unknown. To target type 2 cells specifically, we used a transgenic mouse line that expresses green fluorescent protein under the control of the tyrosine hydroxylase promoter. Type 2 cells are GABAergic and have an extensive dendritic arbor, which stratifies in the middle of the inner plexiform layer. Our data suggest that type 2 cells comprise two subpopulations with identical physiological properties: one has its somata located in the inner nuclear layer and the other in the ganglion cell layer. Immunostaining with bipolar cell markers suggested that type 2 cells receive excitatory inputs from type 3 OFF and type 5 ON bipolar cells. Consistently, patch-clamp recordings showed that type 2 cells are ON-OFF amacrine cells. Blocking excitatory inputs revealed that different rod and cone pathways are active under scotopic and mesopic light conditions. Blockade of inhibitory inputs led to membrane potential oscillations in type 2 cells, suggesting that GABAergic and glycinergic amacrine cells strongly influence type 2 cell signaling. Among the glycinergic amacrine cells, we identified the VGluT3-immunoreactive amacrine cell as a likely candidate. Collectively, light responses of type 2 cells were remarkably uniform over a wide range of light intensities. These properties point toward a general function of type 2 cells that is maintained under scotopic and mesopic conditions.

Burden of invasive cervical cancer in North Carolina.

OBJECTIVE: Cervical cancer causes over 4000 deaths yearly in the United States, although highly preventable through vaccination, screening, and early treatment. We aimed to determine demographic correlates for cervical cancer in North Carolina to identify target populations for interventions and to create a framework for state-level analyses. METHOD: Data on all reported invasive cervical cancer cases from 1998 to 2007 were obtained from the North Carolina Central Cancer Registry. Age-adjusted incidence and mortality rates were estimated using population data from the National Center for Health Statistics. RESULTS: Cervical cancer incidence and mortality rates varied greatly by county and were inversely associated with county prosperity. Hispanic women had the highest incidence rate, black women the highest mortality rate, although white women accounted for most cases. Incidence rates remained fairly steady above age 35 and mortality rates steadily increased with age. A later stage at diagnosis was more common for older women and for women without private insurance. CONCLUSION: Registry-based assessment illustrates the economic, racial, and age disparities associated with cervical cancer. This localized focus on demographic correlates is an important step toward eliminating this preventable disease and offers a template for cervical cancer prevention programs in other states.

Femoroacetabular Impingement - Factors Associated with the Presence of Deep Injuries of the Chondrolabral Junction.

Objective The purpose of the present study was to evaluate factors associated with the presence of deep chondral lesions (Konan/Haddad grades III and IV) in patients submitted to hip arthroscopy to treat femoroacetabular impingement (FAI). Method This was a prospective, cross-sectional study of a series of 125 consecutive hip arthroscopies performed between May 2016 and May 2017. After applying the exclusion criteria, 107 hips of 92 patients submitted to surgical treatment for mixed and CAM FAI were analyzed. For purposes of analysis, the present study considered groups with lesions considered mild and deep, which were associated with symptom score, lateral coverage angle, α angle, age, gender, and radiological classification of arthrosis. Results with a p -value < 0.05 were considered statistically significant. Results Patients whose hips had lesions considered deep had significantly higher nonarthritic hip scores (NAHSs) than those whose hips presented lesions considered mild or who did not present chondral lesions (67.9 ± 19.4 versus 57.0 ± 21.9, p = 0.027). The prevalence of deep lesions was higher in hips with Tonnis 1 compared with hips with Tonnis 0: 15 (55.6%) versus 10 (12.7%), respectively, p < 0.001. Men presented a higher prevalence of grades III and IV lesions than women, 23 (34.3%) versus 2 (5.0%), p = 0.001, and had significantly higher functional scores (65.6 ± 19.6 versus 49.3 ± 21.6, p < 0.001). Conclusion Men presented a higher prevalence of deep lesions. Hips classified as Tonnis 1 presented a 4.4-fold higher probability of presenting these lesions. Patients with deep chondrolabral lesions had a better preoperative functional score.

Angiotensin-Receptor-Associated Protein Modulates Ca2+ Signals in Photoreceptor and Mossy Fiber cells.

Fast, precise and sustained neurotransmission requires graded Ca2+ signals at the presynaptic terminal. Neurotransmitter release depends on a complex interplay of Ca2+ fluxes and Ca2+ buffering in the presynaptic terminal that is not fully understood. Here, we show that the angiotensin-receptor-associated protein (ATRAP) localizes to synaptic terminals throughout the central nervous system. In the retinal photoreceptor synapse and the cerebellar mossy fiber-granule cell synapse, we find that ATRAP is involved in the generation of depolarization-evoked synaptic Ca2+ transients. Compared to wild type, Ca2+ imaging in acutely isolated preparations of the retina and the cerebellum from ATRAP knockout mice reveals a significant reduction of the sarcoendoplasmic reticulum (SR) Ca2+-ATPase (SERCA) activity. Thus, in addition to its conventional role in angiotensin signaling, ATRAP also modulates presynaptic Ca2+ signaling within the central nervous system.

Light responses in the mouse retina are prolonged upon targeted deletion of the HCN1 channel gene.

Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels contribute to pacemaker activity, and co-determine the integrative behaviour of neurons and shape their response to synaptic stimulation. Four channel isoforms, HCN1-4, have been described in mammals. Recent studies showed particularly strong expression of HCN1 channels in rods and cones of the rat retina, suggesting that HCN1 channels are involved in the shaping of light responses in both types of photoreceptors. Therefore, the loss of HCN1 channels should lead to pronounced changes in light-induced electrical responses under both scotopic and photopic conditions. This was tested using a mouse transgenic approach. We used immunohistochemistry and patch-clamp recording to study the distribution of HCN1 channels in the mouse retina. HCN1 channels were strongly expressed in rod and cone photoreceptors, as well as in some bipolar, amacrine and ganglion cell types. In electroretinograms (ERGs) from animals in which the HCN1 channel gene had been knocked out, the b-wave amplitudes were unaltered (scotopic conditions) or somewhat reduced (photopic conditions), whereas the duration of both scotopic and photopic ERG responses was strikingly prolonged. Our data suggest that in visual information processing, shortening and shaping of light responses by activation of HCN1 at the level of the photoreceptors is an important step in both scotopic and photopic pathways.

GlyT1 determines the glycinergic phenotype of amacrine cells in the mouse retina.

The amino acid glycine acts as a neurotransmitter at both inhibitory glycinergic and excitatory glutamatergic synapses predominantly in caudal regions of the central nervous system but also in frontal brain regions and the retina. After its presynaptic release and binding to postsynaptic receptors at caudal glycinergic synapses, two high-affinity glycine transporters GlyT1 and GlyT2 remove glycine from the extracellular space. Glycinergic neurons express GlyT2, which is essential for the presynaptic replenishment of the transmitter, while glial-expressed GlyT1 was shown to control the extracellular glycine concentration. Here we show that GlyT1 expressed by glycinergic amacrine cells of the retina does not only contribute to the control of the extracellular glycine concentration in the retina but is also essential for the maintenance of the glycinergic transmitter phenotype of this cell population. Specifically, loss of GlyT1 from the glycinergic AII amacrine cells impairs AII-mediated glycinergic neurotransmission and alters regulation of the extracellular glycine concentration, without changes in the overall distribution and/or size of glycinergic synapses. Taken together, our results suggest that GlyT1 expressed by amacrine cells in the retina combines functions covered by neuronal GlyT2 and glial GlyT1 at caudal glycinergic synapses.

Use of oral anticoagulants for the prevention of thromboembolic events in the post-operative period of hip arthroplasty: a systematic review.

Oral anticoagulants are being used in the postoperative period of hip arthroplasty to prevent of thromboembolic events, create doubts as to the effectiveness of thromboprophylaxis and reduce the risk of hemorrhage. This systematic revision is aimed at evaluating the use of oral anticoagulants in the prevention of thromboembolic events in the postoperative period of patients undergoing hip arthroplasty. Research with descriptors found on PubMed, BVS, and the CAPES portal for medical journal publications from September 2015 to June 2016, from the last ten years (2005-2015), complete, free, and written in Portuguese and in English were the methods used. The results of the studies showed some cases of pulmonary embolism, deep vein thrombosis, and bleeding; even then, the NOACs were effective in preventing thromboembolic events. There is no consensus regarding the prophylaxis method for these events, which is why the challenge is to obtain high levels of prevention while minimizing the adverse effects. The most studied oral anticoagulant was rivaroxaban (67%). The three drugs that were studied have shown to be effective in preventing thromboembolic events, but the best results were obtained with rivaroxaban 10 mg, one tablet daily; treatment duration ranged from 30 to 35 days with oral anticoagulants and from 28 to 42 days with anti-platelet drugs.

Os anticoagulantes orais usados no pós-operatório de artroplastia de quadril para prevenção de eventos tromboembólicos geram dúvidas a respeito da efetividade tromboprofilática e da redução de riscos hemorrágicos. Para isso, esta revisão sistemática tem como objetivo avaliar o uso de anticoagulantes orais para prevenção de eventos tromboembólicos no pós-operatório de pacientes submetidos a artroplastia de quadril. Os métodos usados foram pesquisas nas bases de dados indexadas do PubMed, BVS e periódicos da Capes de setembro de 2015 a junho de 2016, dos últimos dez anos, completos, livres e nos idiomas inglês e português. Os resultados apresentaram alguns casos de embolia pulmonar, trombose venosa profunda e sangramentos; apesar disso, os NACOs foram considerados, pelos estudos citados, eficazes na prevenção de eventos tromboembólicos. Os três medicamentos estudados mostraram-se importantes na prevenção de eventos tromboembólicos, mas os melhores resultados profiláticos foram obtidos com Rivaroxaban 10 mg, uma vez ao dia, com duração entre 30 e 35 dias com anticoagulantes orais e 28 a 42 dias com antiagregante plaquetário.

Femoroacetabular Impingement - Factors Associated with the Presence of Deep Injuries of the Chondrolabral Junction / Impacto femoroacetabular - Fatores associados à presença de lesões profundas da junção condrolabral

Abstract Objective The purpose of the present study was to evaluate factors associated with the presence of deep chondral lesions (Konan/Haddad grades III and IV) in patients submitted to hip arthroscopy to treat femoroacetabular impingement (FAI). Method This was a prospective, cross-sectional study of a series of 125 consecutive hip arthroscopies performed between May 2016 and May 2017. After applying the exclusion criteria, 107 hips of 92 patients submitted to surgical treatment for mixed and CAM FAI were analyzed. For purposes of analysis, the present study considered groups with lesions considered mild and deep, which were associated with symptom score, lateral coverage angle, α angle, age, gender, and radiological classification of arthrosis. Results with a p-value < 0.05 were considered statistically significant. Results Patients whose hips had lesions considered deep had significantly higher nonarthritic hip scores (NAHSs) than those whose hips presented lesions considered mild or who did not present chondral lesions (67.9 ± 19.4 versus 57.0 ± 21.9, p= 0.027). The prevalence of deep lesions was higher in hipswith Tonnis 1 compared with hips with Tonnis 0: 15(55.6%) versus 10 (12.7%), respectively, p< 0.001.Men presented a higher prevalence of grades III and IV lesions than women, 23 (34.3%) versus 2 (5.0%), p= 0.001, and had significantly higher functional scores (65.6 ± 19.6 versus 49.3 ± 21.6, p< 0.001). Conclusion Men presented a higher prevalence of deep lesions. Hips classified as Tonnis 1 presented a 4.4-fold higher probability of presenting these lesions. Patients with deep chondrolabral lesions had a better preoperative functional score.

Resumo Objetivo Avaliar os fatores associados à presença de lesões condrais profundas (graus III e IV de Konan/Haddad) em pacientes submetidos à artroscopia do quadril para tratamento do impacto femoroacetabular (IFA). Método Estudo transversal, prospectivo, de uma série de 125 artroscopias consecutivas do quadril feitas entre maio de 2016 e maio de 2017. Depois de aplicados os critérios de exclusão, foram analisados 107 quadris de 92 pacientes submetidos a tratamento cirúrgico do IFA dos tipos misto e CAM. Para fins de análise, os grupos foram divididos entre lesões consideradas leves e profundas, e foi feita associação comescore de sintomas, ângulo de cobertura lateral, ângulo alfa, idade, gênero, e classificação radiológica de artrose. Foramconsiderados como estatisticamente significativos testes com valor de probabilidade < 0,05. Resultados Pacientes cujos quadris apresentaram lesões consideradas profundas tiveramescores de quadril não artrítico (NAHSs, na sigla em inglês) significativamentemaiores do que aqueles cujos quadris apresentavam lesões consideradas leves ou não apresentavamlesão condrolabral (67,9 ± 19,4 versus 57,0 ± 21,9; p= 0,027). Aprevalência de lesões profundas foi maior nos quadris Tonnis 1 do que nos que apresentaramTonnis 0: 15 (55,6%) versus 10 (12,7%), respectivamente; p< 0,001. Homens apresentaram melhores escores funcionais e maior prevalência de lesões graus III e IVdoque as mulheres: 65,6 ± 19,6 versus 49,3 ± 21,6; p< 0,001, e 23 (34,3%) versus 2 (5,0%), p= 0,001, respectivamente. Conclusão Homens apresentaram maior prevalência de lesões profundas. Quadris Tonnis 1 tiveram um risco 4,4 vezes maior de apresentar essas lesões. Pacientes com lesões condrolabrais profundas apresentaram melhor escore funcional pré-operatório.

Use of oral anticoagulants for the prevention of thromboembolic events in the post-operative period of hip arthroplasty: a systematic review / Uso de anticoagulantes orais para prevenção de eventos tromboembólicos no pós-operatório de artroplastia de quadril: revisão sistemática

ABSTRACT Oral anticoagulants are being used in the postoperative period of hip arthroplasty to prevent of thromboembolic events, create doubts as to the effectiveness of thromboprophylaxis and reduce the risk of hemorrhage. This systematic revision is aimed at evaluating the use of oral anticoagulants in the prevention of thromboembolic events in the postoperative period of patients undergoing hip arthroplasty. Research with descriptors found on PubMed, BVS, and the CAPES portal for medical journal publications from September 2015 to June 2016, from the last ten years (2005-2015), complete, free, and written in Portuguese and in English were the methods used. The results of the studies showed some cases of pulmonary embolism, deep vein thrombosis, and bleeding; even then, the NOACs were effective in preventing thromboembolic events. There is no consensus regarding the prophylaxis method for these events, which is why the challenge is to obtain high levels of prevention while minimizing the adverse effects. The most studied oral anticoagulant was rivaroxaban (67%). The three drugs that were studied have shown to be effective in preventing thromboembolic events, but the best results were obtained with rivaroxaban 10 mg, one tablet daily; treatment duration ranged from 30 to 35 days with oral anticoagulants and from 28 to 42 days with anti-platelet drugs.

RESUMO Os anticoagulantes orais usados no pós-operatório de artroplastia de quadril para prevenção de eventos tromboembólicos geram dúvidas a respeito da efetividade tromboprofilática e da redução de riscos hemorrágicos. Para isso, esta revisão sistemática tem como objetivo avaliar o uso de anticoagulantes orais para prevenção de eventos tromboembólicos no pós-operatório de pacientes submetidos a artroplastia de quadril. Os métodos usados foram pesquisas nas bases de dados indexadas do PubMed, BVS e periódicos da Capes de setembro de 2015 a junho de 2016, dos últimos dez anos, completos, livres e nos idiomas inglês e português. Os resultados apresentaram alguns casos de embolia pulmonar, trombose venosa profunda e sangramentos; apesar disso, os NACOs foram considerados, pelos estudos citados, eficazes na prevenção de eventos tromboembólicos. Os três medicamentos estudados mostraram-se importantes na prevenção de eventos tromboembólicos, mas os melhores resultados profiláticos foram obtidos com Rivaroxaban 10 mg, uma vez ao dia, com duração entre 30 e 35 dias com anticoagulantes orais e 28 a 42 dias com antiagregante plaquetário.

Electrophysiological characterization of GFP-expressing cell populations in the intact retina.

Studying the physiological properties and synaptic connections of specific neurons in the intact tissue is a challenge for those cells that lack conspicuous morphological features or show a low population density. This applies particularly to retinal amacrine cells, an exceptionally multiform class of interneurons that comprise roughly 30 subtypes in mammals(1). Though being a crucial part of the visual processing by shaping the retinal output(2), most of these subtypes have not been studied up to now in a functional context because encountering these cells with a recording electrode is a rare event. Recently, a multitude of transgenic mouse lines is available that express fluorescent markers like green fluorescent protein (GFP) under the control of promoters for membrane receptors or enzymes that are specific to only a subset of neurons in a given tissue(3,4). These pre-labeled cells are therefore accessible to directed microelectrode targeting under microscopic control, permitting the systematic study of their physiological properties in situ. However, excitation of fluorescent markers is accompanied by the risk of phototoxicity for the living tissue. In the retina, this approach is additionally hampered by the problem that excitation light causes appropriate stimulation of the photoreceptors, thus inflicting photopigment bleaching and transferring the retinal circuits into a light-adapted condition. These drawbacks are overcome by using infrared excitation delivered by a mode-locked laser in short pulses of the femtosecond range. Two-photon excitation provides energy sufficient for fluorophore excitation and at the same time restricts the excitation to a small tissue volume minimizing the hazards of photodamage(5). Also, it leaves the retina responsive to visual stimuli since infrared light (>850 nm) is only poorly absorbed by photopigments(6). In this article we demonstrate the use of a transgenic mouse retina to attain electrophysiological in situ recordings from GFP-expressing cells that are visually targeted by two-photon excitation. The retina is prepared and maintained in darkness and can be subjected to optical stimuli which are projected through the condenser of the microscope (Figure 1). Patch-clamp recording of light responses can be combined with dye filling to reveal the morphology and to check for gap junction-mediated dye coupling to neighboring cells, so that the target cell can by studied on different experimental levels.

Modulation of rod photoreceptor output by HCN1 channels is essential for regular mesopic cone vision.

Retinal photoreceptors permit visual perception over a wide range of lighting conditions. Rods work best in dim, and cones in bright environments, with considerable functional overlap at intermediate (mesopic) light levels. At many sites in the outer and inner retina where rod and cone signals interact, gap junctions, particularly those containing Connexin36, have been identified. However, little is known about the dynamic processes associated with the convergence of rod and cone system signals into ON- and OFF-pathways. Here we show that proper cone vision under mesopic conditions requires rapid adaptational feedback modulation of rod output via hyperpolarization-activated and cyclic nucleotide-gated channels 1. When these channels are absent, sustained rod responses following bright light exposure saturate the retinal network, resulting in a loss of downstream cone signalling. By specific genetic and pharmacological ablation of key signal processing components, regular cone signalling can be restored, thereby identifying the sites involved in functional rod-cone interactions.

Bat eyes have ultraviolet-sensitive cone photoreceptors.

Mammalian retinae have rod photoreceptors for night vision and cone photoreceptors for daylight and colour vision. For colour discrimination, most mammals possess two cone populations with two visual pigments (opsins) that have absorption maxima at short wavelengths (blue or ultraviolet light) and long wavelengths (green or red light). Microchiropteran bats, which use echolocation to navigate and forage in complete darkness, have long been considered to have pure rod retinae. Here we use opsin immunohistochemistry to show that two phyllostomid microbats, Glossophaga soricina and Carollia perspicillata, possess a significant population of cones and express two cone opsins, a shortwave-sensitive (S) opsin and a longwave-sensitive (L) opsin. A substantial population of cones expresses S opsin exclusively, whereas the other cones mostly coexpress L and S opsin. S opsin gene analysis suggests ultraviolet (UV, wavelengths <400 nm) sensitivity, and corneal electroretinogram recordings reveal an elevated sensitivity to UV light which is mediated by an S cone visual pigment. Therefore bats have retained the ancestral UV tuning of the S cone pigment. We conclude that bats have the prerequisite for daylight vision, dichromatic colour vision, and UV vision. For bats, the UV-sensitive cones may be advantageous for visual orientation at twilight, predator avoidance, and detection of UV-reflecting flowers for those that feed on nectar.

The transmembrane segment S6 determines cation versus anion selectivity of TRPM2 and TRPM8.

TRPM2 and TRPM8, closely related members of the transient receptor potential (TRP) family, are cation channels activated by quite different mechanisms. Their transmembrane segments S5 and S6 are highly conserved. To identify common structures in S5 and S6 that govern interaction with the pore, we created a chimera in which the S5-pore-S6 region of TRPM8 was inserted into TRPM2, along with a lysine at each transition site. Currents through this chimera were induced by ADP-ribose (ADPR) in cooperation with Ca(2+). In contrast to wild-type TRPM2 channels, currents through the chimera were carried by Cl(-), as demonstrated in ion substitution experiments using the cation N-methyl-D-glucamine (NMDG) and the anion glutamate. Extracellular NMDG had no effects. The substitution of either intracellular or extracellular Cl(-) with glutamate shifted the reversal potential, decreased the current amplitude and induced a voltage-dependent block relieved by depolarization. The lysine in S6 was responsible for the anion selectivity; insertion of a lysine into corresponding sites within S6 of either TRPM2 or TRPM8 created anion channels that were activated by ADPR (TRPM2 I1045K) or by cold temperatures (TRPM8 V976K). The positive charge of the lysine was decisive for the glutamate block because the mutant TRPM2 I1045H displayed cation currents that were blocked at acidic but not alkaline intracellular pH values. We conclude that the distal part of S6 is crucial for the discrimination of charge. Because of the high homology of S6 in the whole TRP family, this new role of S6 may apply to further TRP channels.