One-year follow-up of continuous aspiration mechanical thrombectomy for the management of intermediate-high and high-risk pulmonary embolism: what is the line between utility and futility?

Introduction

Percutaneous catheter-directed treatments have emerged at the last decade for the management of acute high- or intermediate-high-risk pulmonary embolism (PE). Good short-term efficacy and safety have been published, but there are limited data regarding medium- to long-term outcomes.

Purpose

This study aimed to evaluate 1-year all-cause mortality of acute high- and intermediate-high-risk PE patients (pts) treated with continuous aspiration mechanical thrombectomy.

Methods

Twenty-nine consecutive pts with acute central PE (mean age 67.2±14.4 years; 72.4% female; 24.1% active cancer; Charlson comorbidity index 4.5±2.1; 82.8% in class>III of original PESI score; 44.8% high-risk PE) were treated with the Indigo Mechanical Thrombectomy System (Penumbra, Inc) between 03/2018 and 03/2020. Clinical success was defined as improvement in hemodynamic and/or oxygenation parameters or pulmonary hypertension or right heart strain at 48 hours after intervention plus survival to hospital discharge. Data regarding severe adverse events potentially related to the procedure, in-hospital and 1-year all-cause mortality were collected.

Results

Clinical success was 75.9%, with a significant improvement in mean paO2/fiO2 ratio (+77.1±103.2; p<0.01), shock index (−0.4±0.4, p<0.01), need for aminergic support (−75.0%, p<0.01), right ventricular function (66.6%, p<0.01) and systolic pulmonary arterial pressure (−10.2±11.5mmHg, p<0.01) at 48 hours after procedure. In-hospital survival rate was 82.8% but severe adverse events potentially related to the procedure occurred in 3 pts (10.3%). One-year follow-up was completed in 93.1% of cases and all-cause mortality rate was 34.5% (n=10 of which half occurred during the index hospital stay). Higher scores of Charlson comorbidity index (5.8±1.9 vs 3.7±1.9, p=0.01) and de novo atrial fibrillation at admission (40% vs 0%, p<0.01) were associated with higher 1-year all-cause mortality occurrence and were identified as 2 independent risk predictors by multivariate Cox regression. Kaplan-Meier curves confirmed its significant influence in 1-year survival free of adverse event (Figure). Time among diagnosis and percutaneous treatment (p=0.99), PESI score (p=0.24) and other clinical, haemodynamic and echocardiographic features did not influence mortality and suggest similarity of the PE severity at baseline. Technical characteristics were also not associated with mortality.

Conclusions

Aspiration thrombectomy for acute high- and intermediate-high-risk PE was feasible with a high clinical success rate. One-year all-cause mortality rate was elevated and predicted by high comorbidity index and de novo atrial fibrillation at admission. This data support the national expansion of this new PE treatment, but probably and as similar to other invasive techniques, we need to take into account comorbidities and avoid futility in multimorbidity pts.

Funding Acknowledgement

Type of funding sources: None.

Activity-dependent regulation of mitochondrial motility in developing cortical dendrites

Developing neurons form synapses at a high rate. Synaptic transmission is very energy-demanding and likely requires ATP production by mitochondria nearby. Mitochondria might be targeted to active synapses in young dendrites, but whether such motility regulation mechanisms exist is unclear. We investigated the relationship between mitochondrial motility and neuronal activity in the primary visual cortex of young mice in vivo and in slice cultures. During the first 2 postnatal weeks, mitochondrial motility decreases while the frequency of neuronal activity increases. Global calcium transients do not affect mitochondrial motility. However, individual synaptic transmission events precede local mitochondrial arrest. Pharmacological stimulation of synaptic vesicle release, but not focal glutamate application alone, stops mitochondria, suggesting that an unidentified factor co-released with glutamate is required for mitochondrial arrest. A computational model of synaptic transmission-mediated mitochondrial arrest shows that the developmental increase in synapse number and transmission frequency can contribute substantially to the age-dependent decrease of mitochondrial motility.

Somatostatin interneurons restrict cell recruitment to retinally driven spontaneous activity in the developing cortex

During early development, before the eyes open, synaptic refinement of sensory networks depends on activity generated by developing neurons themselves. In the mouse visual system, retinal cells spontaneously depolarize and recruit downstream neurons to bursts of activity, where the number of recruited cells determines the resolution of synaptic retinotopic refinement. Here we show that during the second post-natal week in mouse visual cortex, somatostatin (SST)-expressing interneurons control the recruitment of cells to retinally driven spontaneous activity. Suppressing SST interneurons increases cell participation and allows events to spread farther along the cortex. During the same developmental period, a second type of high-participation, retina-independent event occurs. During these events, cells receive such large excitatory charge that inhibition is overwhelmed and large parts of the cortex participate in each burst. These results reveal a role of SST interneurons in restricting retinally driven activity in the visual cortex, which may contribute to the refinement of retinotopy.

Adaptation of spontaneous activity in the developing visual cortex

Spontaneous activity drives the establishment of appropriate connectivity in different circuits during brain development. In the mouse primary visual cortex, two distinct patterns of spontaneous activity occur before vision onset: local low-synchronicity events originating in the retina and global high-synchronicity events originating in the cortex. We sought to determine the contribution of these activity patterns to jointly organize network connectivity through different activity-dependent plasticity rules. We postulated that local events shape cortical input selectivity and topography, while global events homeostatically regulate connection strength. However, to generate robust selectivity, we found that global events should adapt their amplitude to the history of preceding cortical activation. We confirmed this prediction by analyzing in vivo spontaneous cortical activity. The predicted adaptation leads to the sparsification of spontaneous activity on a slower timescale during development, demonstrating the remarkable capacity of the developing sensory cortex to acquire sensitivity to visual inputs after eye-opening.

Oxytocin Shapes Spontaneous Activity Patterns in the Developing Visual Cortex by Activating Somatostatin Interneurons

Spontaneous network activity shapes emerging neuronal circuits during early brain development prior to sensory perception. However, how neuromodulation influences this activity is not fully understood. Here, we report that the neuromodulator oxytocin differentially shapes spontaneous activity patterns across sensory cortices. In vivo, oxytocin strongly decreased the frequency and pairwise correlations of spontaneous activity events in the primary visual cortex (V1), but it did not affect the frequency of spontaneous network events in the somatosensory cortex (S1). Patch-clamp recordings in slices and RNAscope showed that oxytocin affects S1 excitatory and inhibitory neurons similarly, whereas in V1, oxytocin targets only inhibitory neurons. Somatostatin-positive (SST+) interneurons expressed the oxytocin receptor and were activated by oxytocin in V1. Accordingly, pharmacogenetic silencing of V1 SST+ interneurons fully blocked oxytocin's effect on inhibition in vitro as well its effect on spontaneous activity patterns in vivo. Thus, oxytocin decreases the excitatory/inhibitory (E/I) ratio by recruiting SST+ interneurons and modulates specific features of V1 spontaneous activity patterns that are crucial for the wiring and refining of developing sensory circuits.

A BDNF-Mediated Push-Pull Plasticity Mechanism for Synaptic Clustering

During development, activity-dependent synaptic plasticity refines neuronal networks with high precision. For example, spontaneous activity helps sorting synaptic inputs with similar activity patterns into clusters to enhance neuronal computations in the mature brain. Here, we show that TrkB activation and postsynaptic brain-derived neurotrophic factor (BDNF) are required for synaptic clustering in developing hippocampal neurons. Moreover, BDNF and TrkB modulate transmission at synapses depending on their clustering state, indicating that endogenous BDNF/TrkB signaling stabilizes locally synchronized synapses. Together with our previous data on proBDNF/p75^NTR signaling, these findings suggest a push-pull plasticity mechanism for synaptic clustering: BDNF stabilizes clustered synapses while proBDNF downregulates out-of-sync synapses. This idea is supported by our observation that synaptic clustering requires matrix-metalloproteinase-9 activity, a proBDNF-to-BDNF converting enzyme. Finally, NMDA receptor activation mediates out-of-sync depression upstream of proBDNF signaling. Together, these data delineate an efficient plasticity mechanism where proBDNF and mature BDNF establish synaptic clustering through antagonistic modulation of synaptic transmission.

Spontaneous Activity Patterns Are Altered in the Developing Visual Cortex of the Fmr1 Knockout Mouse

Fragile X syndrome (FXS) is the most prevalent inherited cause of autism and is accompanied by behavioral and sensory deficits. Errors in the wiring of the brain during early development likely contribute to these deficits, but the underlying mechanisms are unclear. Spontaneous activity patterns, which are required for fine-tuning neuronal networks before the senses become active, are perturbed in rodent models of FXS. Here, we investigated spontaneous network activity patterns in the developing visual cortex of the Fmr1 knockout mouse using in vivo calcium imaging during the second postnatal week, before eye opening. We found that while the frequency, mean amplitude and duration of spontaneous network events were unchanged in the knockout mouse, pair-wise correlations between neurons were increased compared to wild type littermate controls. Further analysis revealed that interneuronal correlations were not generally increased, rather that low-synchronization events occurred relatively less frequently than high-synchronization events. Low-, but not high-, synchronization events have been associated with retinal inputs previously. Since we found that spontaneous retinal waves were normal in the knockout, our results suggest that peripherally driven activity is underrepresented in the Fmr1 KO visual cortex. Therefore, we propose that central gating of retinal inputs may be affected in FXS and that peripherally and centrally driven activity patterns are already unbalanced before eye opening in this disorder.

[Maculopathy with optic nerve pits : Morphological criteria in SD-OCT]

PURPOSE

Optic pit is a congenital anomaly with malformation similar to coloboma of the optic disc. The cause of optic pit maculopathy is controversial. We used high resolution OCT to investigate changes in the vitreoretinal and vitreopapillary transition within optic pit eyes.

METHODS

The vitreoretinal and vitreo-papillary transition of 12 eyes was accurately analyzed using SD-OCT. We registered the following criteria: liquefaction of prepapillary vitreous, papillary vitreous traction, discontinuity within the hyaloid cortex and communication spaces between pit and retinal edema.

RESULTS

Communication gaps between pit and retinal edema were identified in 8 eyes. 4 eyes had a papillary vitreous traction. 4 showed a discontinuity in the hyaloid cortex. 2 of the 12 patients showed no maculopathy in SD-OCT. Those patients had an adjacent papillary vitreous without prepapillary liquefaction. However all eyes showed vitreous liquefaction at some stage premacullary or prepapillary.

CONCLUSION

Yet the cause of optic pit maculopathy is not clearly understood. High resolution OCT imaging provides a very detailed assessment of the vitreoretinal transition prepapillary and premacullary, however with limited penetration depth and analyzation of deeper lying structures. Our observations suggest that prepapillary liquefaction and pressure gradients within cerebrospinal and intraokular pressure could be key factors.

[Primary enucleation in an avulsion injury : A high-risk procedure under phenprocoumon]

The case of a 77-year-old woman with trauma after a fall is reported. On clinical examination, an avulsion injury was found in the left eye with dual optic nerve dissection. An INR of 3.3 was determined in a perioperative blood sample. The given conditions forced the rare but urgent indication for primary enucleation with hemostasis. Oral anticoagulation presented perioperative high risk, especially due to the potential risk of bleeding from the ophthalmic artery.

Mapping Synaptic Inputs of Developing Neurons Using Calcium Imaging

Studying changing synaptic activity patterns during development provides a wealth of information on how activity-dependent processes shape synaptic connectivity. In this chapter we introduce a method that combines whole-cell electrophysiology with calcium imaging to map functional synaptic sites on the dendritic tree and follow their activity over time. The key strength of this method lies in its ability to distinguish between synaptic and non-synaptic calcium signaling by their coincidence with synaptic currents measured at the soma. Next to the required materials and protocols that are necessary to perform these experiments, we thoroughly discuss how the acquired data can be analyzed. Since this method can be employed in many neuronal systems we believe that it can be a valuable tool to study developmental changes in synaptic connectivity.

Mitochondrial Dynamics in Visual Cortex Are Limited In Vivo and Not Affected by Axonal Structural Plasticity

Mitochondria buffer intracellular Ca²⁺ and provide energy [1]. Because synaptic structures with high Ca²⁺ buffering [2-4] or energy demand [5] are often localized far away from the soma, mitochondria are actively transported to these sites [6-11]. Also, the removal and degradation of mitochondria are tightly regulated [9, 12, 13], because dysfunctional mitochondria are a source of reactive oxygen species, which can damage the cell [14]. Deficits in mitochondrial trafficking have been proposed to contribute to the pathogenesis of Parkinson's disease, schizophrenia, amyotrophic lateral sclerosis, optic atrophy, and Alzheimer's disease [13, 15-19]. In neuronal cultures, about a third of mitochondria are motile, whereas the majority remains stationary for several days [8, 20]. Activity-dependent mechanisms cause mitochondria to stop at synaptic sites [7, 8, 20, 21], which affects synapse function and maintenance. Reducing mitochondrial content in dendrites decreases spine density [22, 23], whereas increasing mitochondrial content or activity increases it [7]. These bidirectional interactions between synaptic activity and mitochondrial trafficking suggest that mitochondria may regulate synaptic plasticity. Here we investigated the dynamics of mitochondria in relation to axonal boutons of neocortical pyramidal neurons for the first time in vivo. We find that under these circumstances practically all mitochondria are stationary, both during development and in adulthood. In adult visual cortex, mitochondria are preferentially localized at putative boutons, where they remain for several days. Retinal-lesion-induced cortical plasticity increases turnover of putative boutons but leaves mitochondrial turnover unaffected. We conclude that in visual cortex in vivo, mitochondria are less dynamic than in vitro, and that structural plasticity does not affect mitochondrial dynamics.

The Wiring of Developing Sensory Circuits-From Patterned Spontaneous Activity to Synaptic Plasticity Mechanisms

In order to accurately process incoming sensory stimuli, neurons must be organized into functional networks, with both genetic and environmental factors influencing the precise arrangement of connections between cells. Teasing apart the relative contributions of molecular guidance cues, spontaneous activity and visual experience during this maturation is on-going. During development of the sensory system, the first, rough organization of connections is created by molecular factors. These connections are then modulated by the intrinsically generated activity of neurons, even before the senses have become operational. Spontaneous waves of depolarizations sweep across the nervous system, placing them in a prime position to strengthen correct connections and weaken others, shaping synapses into a useful network. A large body of work now support the idea that, rather than being a mere side-effect of the system, spontaneous activity actually contains information which readies the nervous system so that, as soon as the senses become active, sensory information can be utilized by the animal. An example is the neonatal mouse. As soon as the eyelids first open, neurons in the cortex respond to visual information without the animal having previously encountered structured sensory input (Cang et al., 2005b; Rochefort et al., 2011; Zhang et al., 2012; Ko et al., 2013). In vivo imaging techniques have advanced considerably, allowing observation of the natural activity in the brain of living animals down to the level of the individual synapse. New (opto)genetic methods make it possible to subtly modulate the spatio-temporal properties of activity, aiding our understanding of how these characteristics relate to the function of spontaneous activity. Such experiments have had a huge impact on our knowledge by permitting direct testing of ideas about the plasticity mechanisms at play in the intact system, opening up a provocative range of fresh questions. Here, we intend to outline the most recent descriptions of spontaneous activity patterns in rodent developing sensory areas, as well as the inferences we can make about the information content of those activity patterns and ideas about the plasticity rules that allow this activity to shape the young brain.

[Materials/Biomaterials in Clinical Practice - a Short Review and Current Trends]

Biomaterials play a major role in interventional medicine and surgery. However, the development of biomaterials is still in its early phases in spite of the huge progress made within the last decades. On the one hand, this is because our knowledge of the molecular and cellular processes associated with biomaterials is still increasing exponentially. On the other hand, a wide variety of advanced materials with highly interesting properties is being developed currently. This review provides a short introduction into the variety of materials in use as well as their application in interventional medicine and surgery. Also the importance of biomaterials for tissue engineering in the field of regenerative medicine and the functionalisation of biomaterials, including sterilisation methods are discussed. For the future, an even broader interdisciplinary scientific collaboration is necessary in order to develop novel biomaterials and facilitate their translation into clinical practice.

Simultaneous patch-clamping and calcium imaging in developing dendrites

Calcium imaging has been used extensively to explore the role of action potential (AP) firing in the development of neuronal structure and synaptic function because increases in intracellular calcium ([Ca(2+)]i) reliably and, within a certain range, linearly reflect neuronal spiking activity. Patterns of APs in individual cells can be deduced from calcium recordings, which have typically been performed at the level of cell bodies. However, neurons are particularly susceptible to phototoxicity when they are illuminated at the soma. Furthermore, for some imaging experiments (e.g., those that address the interactions between dendrites and axons during synapse formation), the cell body of a given neuron may simply not be in the field of view. In these situations, it would be helpful to determine the spiking patterns of a neuron from the calcium activity in its subcellular compartments such as stretches of dendrites or axons. Here, we describe an approach for determining the relationship between AP firing and dendritic calcium transients by simultaneously imaging calcium transients in small dendritic stretches of hippocampal pyramidal neurons in slice cultures from neonatal rats and recording spiking activity with whole-cell patch-clamp recordings in these neurons. These experiments allow us to correlate the electrophysiological spiking pattern with the accompanying changes in the calcium concentration in individual dendritic segments.

The developmental stages of synaptic plasticity

The brain is programmed to drive behaviour by precisely wiring the appropriate neuronal circuits. Wiring and rewiring of neuronal circuits largely depends on the orchestrated changes in the strengths of synaptic contacts. Here, we review how the rules of synaptic plasticity change during development of the brain, from birth to independence. We focus on the changes that occur at the postsynaptic side of excitatory glutamatergic synapses in the rodent hippocampus and neocortex. First we summarize the current data on the structure of synapses and the developmental expression patterns of the key molecular players of synaptic plasticity, N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, as well as pivotal kinases (Ca(2+)/calmodulin-dependent protein kinase II, protein kinase A, protein kinase C) and phosphatases (PP1, PP2A, PP2B). In the second part we relate these findings to important characteristics of the emerging network. We argue that the concerted and gradual shifts in the usage of plasticity molecules comply with the changing need for (re)wiring neuronal circuits.

Simultaneous imaging of structural plasticity and calcium dynamics in developing dendrites and axons

During nervous system development, the formation of synapses between pre- and postsynaptic neurons is a remarkably specific process. Both structural and functional plasticity are critical for the selection of synaptic partners and for the establishment and maturation of synapses. To unravel the respective contributions of structural and functional mechanisms as well as their interactions during synaptogenesis, it is important to directly observe structural changes and functional signaling simultaneously. Here, we present an imaging approach to simultaneously follow changes in structure and function. Differential labeling of individual cells and the neuronal network with distinct dyes allows the study of structural plasticity and changes in calcium signaling associated with neural activity at the same time and with high resolution. This is achieved by bulk loading of neuronal populations with a calcium-sensitive indicator in combination with electroporation of individual cells with a calcium indicator and an additional noncalcium-sensitive dye with a different excitation spectrum. Recordings of the two differently labeled structures can be acquired simultaneously using confocal microscopy. Thus, structural plasticity and calcium dynamics of the individually labeled neuron and the surrounding network can be related to each other. This combined imaging approach can be applied to virtually all systems of neuronal networks to study structure and function. We provide a comprehensive description of the labeling procedure, the imaging parameters, and the important aspects of analysis for simultaneous recordings of structure and function in individual neurons.

Gap junctions in developing thalamic and neocortical neuronal networks

The presence of direct, cytoplasmatic, communication between neurons in the brain of vertebrates has been demonstrated a long time ago. These gap junctions have been characterized in many brain areas in terms of subunit composition, biophysical properties, neuronal connectivity patterns, and developmental regulation. Although interesting findings emerged, showing that different subunits are specifically regulated during development, or that excitatory and inhibitory neuronal networks exhibit various electrical connectivity patterns, gap junctions did not receive much further interest. Originally, it was believed that gap junctions represent simple passageways for electrical and biochemical coordination early in development. Today, we know that gap junction connectivity is tightly regulated, following independent developmental patterns for excitatory and inhibitory networks. Electrical connections are important for many specific functions of neurons, and are, for example, required for the development of neuronal stimulus tuning in the visual system. Here, we integrate the available data on neuronal connectivity and gap junction properties, as well as the most recent findings concerning the functional implications of electrical connections in the developing thalamus and neocortex.

Synaptic clustering during development and learning: the why, when, and how

To contribute to a functional network a neuron must make specific connections and integrate the synaptic inputs that it receives in a meaningful way. Previous modeling and experimental studies have predicted that this specificity could entail a subcellular organization whereby synapses that carry similar information are clustered together on local stretches of dendrite. Recent imaging studies have now, for the first time, demonstrated synaptic clustering during development and learning in different neuronal circuits. Interestingly, this organization is dependent on synaptic activity and most likely involves local plasticity mechanisms. Here we discuss these new insights and give an overview of the candidate plasticity mechanisms that could be involved.

Probing synaptic function in dendrites with calcium imaging

Calcium imaging has become a widely used technique to probe neuronal activity on the cellular and subcellular levels. In contrast to standard electrophysiological methods, calcium imaging resolves sub- and suprathreshold activation patterns in structures as small as fine dendritic branches and spines. This review highlights recent findings gained on the subcellular level using calcium imaging, with special emphasis on synaptic transmission and plasticity in individual spines. Since imaging allows monitoring activity across populations of synapses, it has recently been adopted to investigate how dendrites integrate information from many synapses. Future experiments, ideally carried out in vivo, will reveal how the dendritic tree integrates and computes afferent signals. For example, it is now possible to directly test the concept that dendritic inputs are clustered and that single dendrites or dendritic stretches act as independent computational units.

Activity-dependent clustering of functional synaptic inputs on developing hippocampal dendrites

During brain development, before sensory systems become functional, neuronal networks spontaneously generate repetitive bursts of neuronal activity, which are typically synchronized across many neurons. Such activity patterns have been described on the level of networks and cells, but the fine-structure of inputs received by an individual neuron during spontaneous network activity has not been studied. Here, we used calcium imaging to record activity at many synapses of hippocampal pyramidal neurons simultaneously to establish the activity patterns in the majority of synapses of an entire cell. Analysis of the spatiotemporal patterns of synaptic activity revealed a fine-scale connectivity rule: neighboring synapses (<16 μm intersynapse distance) are more likely to be coactive than synapses that are farther away from each other. Blocking spiking activity or NMDA receptor activation revealed that the clustering of synaptic inputs required neuronal activity, demonstrating a role of developmentally expressed spontaneous activity for connecting neurons with subcellular precision.

Peripheral and central inputs shape network dynamics in the developing visual cortex in vivo

Spontaneous network activity constitutes a central theme during the development of neuronal circuitry [1, 2]. Before the onset of vision, retinal neurons generate waves of spontaneous activity that are relayed along the ascending visual pathway [3, 4] and shape activity patterns in these regions [5, 6]. The spatiotemporal nature of retinal waves is required to establish precise functional maps in higher visual areas, and their disruption results in enlarged axonal projection areas (e.g., [7-10]). However, how retinal inputs shape network dynamics in the visual cortex on the cellular level is unknown. Using in vivo two-photon calcium imaging, we identified two independently occurring patterns of network activity in the mouse primary visual cortex (V1) before and at the onset of vision. Acute manipulations of spontaneous retinal activity revealed that one type of network activity largely originated in the retina and was characterized by low synchronicity (L-) events. In addition, we identified a type of high synchronicity (H-) events that required gap junction signaling but were independent of retinal input. Moreover, the patterns differed in wave progression and developmental profile. Our data suggest that different activity patterns have complementary functions during the formation of synaptic circuits in the developing visual cortex.

[Epi-LASIK with a 1000 hertz excimer laser]

PURPOSE

The aim of this study was to evaluate the safety, stability and efficacy of Epi-LASIK with a 1000 hertz excimer laser system.

METHODS

40 eyes of 23 patients underwent an Epi-LASIK procedure using the Gebauer EpiLift and the WaveLight Concept System 1000. Preoperatively as well as 1 month, and 3 months postoperatively, a complete ophthalmic examination, including objective and subjective refraction (UCVA, BCVA) and topography, was performed.

RESULTS

The mean preoperative spherical equivalent (SE) was -4.07 D (SD ± 1.89 D). 1 month after surgery, the spherical equivalent was + 0.01 D (SD ± 0.33 D), and 3 months after surgery -0.06 D (SD ± 0.28 D). 3 months after the Epi-LASIK procedure, 90 % of the patients were within ± 0.5 D of the intended correction, and 97.5 % were within ± 1.0 D of the intended correction. The astigmatism was reduced from -0.77 D (SD ± 0.68 D) to -0.24 D (SD ± 0.29 D) 3 months after surgery. 34 of the 40 eyes had a clear cornea 3 months after surgery, and 6 of the 40 eyes presented with haze grade 0.5.

CONCLUSIONS

In our pilot series of 40 eyes, the use of the 1000 hertz excimer laser did not reveal any specific clinical side effects potentially associated with the use of a high repetition rate. These first results with Epi-LASIK and the WaveLight Concept System 1000 are very promising.

[Culture and susceptibility testing of mycobacteria with VersaTREK]

OBJECTIVES

Our laboratory of microbiology use the VersaTREK/ESP Culture System II for the isolation of mycobacteria. In this study, we evaluate this system for the analysis carried out between April 2009 and March 2010.

METHOD

The Myco bottles are supplemented with growth supplements and an antimicrobial agent solution prior to inoculation with the specimen. The technology of the VersaTREK/ESP Culture System II is based on the detection of headspace pressure changes within a sealed bottle. It monitors changes in either gas production or gas consumption due to microbial growth. A special algorithm has been developed for detection of very slow growing mycobacteria. The bottles are incubated during 42 days. Meanwhile a solid medium is inoculated too. All specimen types can be analysed with this system.

RESULTS

Compared to solid culture, the time needed for detection of positive cultures was significantly shorter for the VersaTREK with a good recovery rate. For isolates recovered in both systems, mean time of detection is respectively 19.1 and 35.6 days for liquid and solid cultures. Mycobacteria identification may be determined using nucleic acid probs directly in Myco VersaTREK or in the solid medium. The susceptibility test of Mycobacteria tuberculosis complex is obtained between six and 13 days for rifampin, isoniazid, ethambutol, streptomycin and pyrasinamide.

CONCLUSION

This system offers a faster diagnosis and is an alternative to other instruments using liquid culture.

[Intravitreal Ranibizumab Injection for the Treatment of Occult and Classic CNV in Exsudative AMD]

BACKGROUND

Double-blind, randomised, placebo-controlled and multicentre studies have proven an increase in visual acuity in one-third of the patients receiving Ranibizumab (0.5 mg) injections, who suffer from exsudative AMD. The purpose of this study was to evaluate the early effects of intravitreal Ranibizumab therapy in patients with mainly occult neovascular AMD in clinical applications.

PATIENTS AND METHODS

In a retrospective cohort study, 91 eyes with occult and classic neovascular AMD were treated with intravitreal injections of Ranibizumab (0.5 mg) at 30-day intervals. The treatment effects were evaluated according to best corrected visual acuity, optical coherence tomography (OCT) and intraocular pressure at baseline as well as 1, 3 and 6 months after the beginning of therapy. Furthermore, fluorescein angiography (FLA) was performed at baseline as well as 3 and 6 months after therapy.

RESULTS

74 % of the patients lost fewer than 15 letters on the EDTRS-scale 6 months after the beginning of therapy. Visual acuity improved by more than 15 letters in 11 % of the patients. Central retinal thickness, measured by OCT, decreased statistically significantly in each control compared to baseline (1 month: p = 0.045; 3 months: p = 0.001; 6 months: p = 0.006). Leakage and membranes, evaluated in FA, worsened in 31 % of the patients; in 67 % the findings were stable. No increase in intraocular pressure was detected.

CONCLUSIONS

Intravitreal application of Ranibizumab was safe and well tolerated. In the clinical situation, visual acuity was stabilised in the short term. As opposed to phase-III studies, no improvement in visual acuity could be accomplished. Cental retinal thickness decreased and findings in fluorescein angiography were stable within a 6-month follow-up period. It is necessary to perform monthly controls and proceed with VA- and OCT-based injections in order to maintain the therapeutic effect. Futher clinical evaluations of Ranibizumab will be necessary to evaluate its long-term treatment effects.

[Six-month clinical results with the light adjustable lens]

PURPOSE

The aim of this study was to evaluate the six-month clinical results of the light adjustable lens (LAL).

MATERIAL AND METHODS

In 20 eyes of 12 patients with cataract a cataract surgery with implantation of a light adjustable lens has been performed. 2 ¹/₂ weeks after surgery all intraocular lens adjustments were carried out. Preoperatively, immediately before the adjustment procedures and 1 month, 3 and 6 months after the adjustment procedure a complete ophthalmic examination was performed.

RESULTS

All cataract surgeries have been carried out without any complications. 2 ¹/₂ weeks after surgery the mean spherical equivalent was + 0.39 D (standard deviation [SD] ± 0.79 D). 6 months after the adjustment procedure the spherical equivalent was -0.07 D (SD ± 0.25 D). 6 months after the adjustment procedure all patients were within ± 0.5 D of intended refraction. Two weeks after surgery the mean cylinder was -0.82 D (SD ± 0.67 D) and was reduced after the adjustments to -0.14 D (SD ± 0.30 D).

DISCUSSION

The light adjustable lens is a new IOL with the ability to correct up to two dioptres of sphere and cylinder after implantation. Our clinical results are promising. Especially the astigmatic correction is very promising, but further clinical investigations with larger patient numbers and longer follow-up are necessary.

[Wavefront-guided and wavefront-optimised LASEK--comparison of clinical results]

PURPOSE

The aim of this study was to compare refractive outcomes and wavefront results in eyes undergoing wavefront-optimised and wavefront-guided LASEK.

METHODS

In this contralateral eye study wavefront-guided LASEK and wavefront-optimised LASEK have been carried out on 30 eyes each. Preoperatively, 1 month, 3 months and 6 months after surgery a full ophthalmological examination was carried out. Preoperatively and 6 months postoperatively additional wavefront measurement have been carried out on all patients.

RESULTS

The mean preoperative refraction in the wavefront-guided group was -4.41 D (SD 1.38 D) and in the wavefront-optimised group -4.62 D (SD 1.86 D). The postoperative refraction was very good in both groups (wavefront-guided -0.06 D, SD 0.18 D; wavefront-optimised -0.03 D, SD 0.21 D). In both groups RMS of higher orders were increased slightly (wavefront-guided from 0.26 to 0.31 microm, wavefront-optimised from 0.27 to 0.32 microm) and also spherical aberrations increased slightly (wavefront-guided from 0.18 to 0.23 microm, wavefront-optimised from 0.16 to 0.21 microm).

CONCLUSIONS

The refractive results with the Concept System 500 in patients with preoperatively low amounts of higher order aberrations after wavefront-guided and wavefront-optimised LASEK are comparable. As good wavefront measurements need a lot of experience and take a lot of time, there is no advantage of wavefront-guided ablation in patients with low preoperative aberrations.

[Synovial chondromatosis]

Primary articular synovial chondromatosis is a benign, self-limiting neoplastic process in which hyaline cartilage nodules form in the synovial tissue. The disease most frequently affects the knee in men, followed by the elbow. The basic feature of this disease is a metaplastic maturation of the mesenchymal cells in the synovial membrane of a joint into cartilage. These cells mature into chondroblasts and form small nodules of cartilage in the synovial membrane. These nodules subsequently enlarge and detach to lie within the joint space. They become free within the joint as multiple small cartilaginous loose bodies nourished by the synovial fluid. The chondrocytes in the loose bodies continue to multiply, and the loose bodies grow in diameter. Calcification appears in the central zone of the loose bodies, and in some cases, enchondral ossification takes place. The operative therapy depends on the stage of the disease: synovectomy with removal of chondral fragments if active intrasynovial disease is present, and removal of the multiple chondral bodies alone in cases of late inactive disease with no synovial abnormalities. Malignant transformation is unusual and can be difficult to distinguish from benign disease.

A simple method for quantitative calcium imaging in unperturbed developing neurons

Calcium imaging has been widely used to address questions of neuronal function and development. To gain deeper insights into the actions of calcium as a second messenger, but also to measure synaptic function, it is necessary to quantify the level of calcium at rest and during calcium transients. While quantification of calcium levels is straightforward when using ratiometric calcium indicators, these dyes have several draw-backs due to their short wavelength excitation spectra, such as light scattering and cytotoxicity. In contrast, many single-wavelength indicators exhibit superior photostability, low phototoxicity, extended dynamic ranges and very high signal to noise ratios. However, quantifying calcium levels in unperturbed neurons has not been performed with these indicators. Here, we explore a new approach for determining the calcium concentration at rest as well as calcium rises during evoked and spontaneous neuronal activity in unperturbed developing neurons using a single-wavelength calcium indicator. We show that measuring the maximal fluorescence at the end of an imaging experiment allows determining calcium levels with high resolution. Specifically, we assessed the limits of calcium measurements with a CCD camera in small neuronal processes and found that even in small diameter dendrites and spines the intracellular calcium concentration and its changes can be estimated accurately. This approach may not only allow mapping patterns of neuronal activity quantitatively with the resolution of single synapses and a few tens of milliseconds, but also facilitate investigating the role of calcium as a second messenger.

[Cut quality of a new femtosecond laser system]

OBJECTIVE

The aim of this study was to evaluate the cut quality and the cellular damage when using a new 200 kHz femtosecond laser.

METHODS

20 porcine eyes and 3 human eyes, not suitable for transplantation, were used for this study. The WaveLight UltraFlap femtosecond laser was used for flap creation. The surface of the cornea, the structure and ultrastructure of the corneal cells and stroma were evaluated thoroughly using light microscopy (HE-, PAS- and Picrosirius red staining), transmission electron microscopy (TEM), and scanning electron microscopy (SEM).

RESULTS

In all eyes, the flap could be lifted very easily and the flap appeared very smooth. Structural and ultrastructural evaluation with light and transmission electron microscopy on epithelium and endothelium showed no side effects of the laser application. The area around the flap cut was minimally affected and the keratocytes and collagen fibres showed minimal alteration due to laser treatment. Scanning electron microscopy revealed in all cases smooth surfaces and precise sidecuts.

CONCLUSIONS

Precise corneal flaps can easily be created with this new femtosecond laser. At the same time, no structural and thermal side effects on corneal epithelium, stroma and endothelium appeared. Hence with this new femtosecond laser corneal flaps could be created easily without noteworthy side effects.

[Photodynamic therapy with verteporfin combined with intravitreal injection of bevacizumab for occult and classic CNV in AMD]

PURPOSE

The aim of this study is to discuss the effect and outcome of a combined photodynamic therapy and intravitreal injection of bevacizumab (1.25 mg) in occult and classic choroidal neovascularisation (CNV) due to AMD. Especially cases of occult CNV with pigment epithelium detachment (PED) are not likely to respond positively to standard photodynamic therapy, often ending up in PED enlargement or tearing of the RPE.

METHODS

In a pilot study involving 23 patients, intravitreal injections of bevacizumab were administered within 12 to 24 hours after standard PDT to reduce the post-PDT increase of proangiogenic and inflammatory factors. Before and at 1, 3 and 6 month after treatment visual acuity and OCT examinations (retinal thickness) were performed.

RESULTS

Mean visual acuity was significantly improved compared to baseline. (VA baseline 20/125, after 1 month 20/80, after 3 months 20/80, and 20/80 after 6 months) and an enlargement of the PED in occult CNV was prevented. We found no RPE rip. OCT findings in patients with occult and classic choroidal neovascularisation 1, 3 and 6 months after combination therapy showed a reduced retinal thickness compared to baseline.

CONCLUSIONS

Photodynamic therapy combined with injection of intravitreal bevacizumab tends to be more effective compared to PDT monotherapy by reducing the post-PDT increase of vascular growth and inflammatory factors. Our short-term results are very promising. Further studies are necessary to show the long-term effect of PDT and anti-VEGF combination therapy.