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.

[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.

[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.

[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.

[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.

[Clinical experience in the treatment of neovascular age-related macular degeneration with pegaptanib]

BACKGROUND

Intravitreal anti-VEGF therapy with Pegaptanib was effective in neovascular AMD in the VISION study. We report our experience with Macugen for the treatment of occult or minimally classic choroidal neovascularisation (CNV) due to age-related macular degeneration (AMD).

PATIENTS AND METHODS

35 eyes of 35 patients with occult CNV or minimally classic CNV due to neovascular AMD not eligible for PDT were treated with intravitreal injection of 0.3 mg Pegaptanib. An average of 2.74 injections per patient was administered. Before, and every 3 months after treatment, visual acuity, intraocular pressure measurement, angiography and OCT examinations were performed. One month after treatment only visual acuity, intraocular pressure measurement, and OCT examinations were performed. Visual acuity measurements and an eye examination were done on the first and second day after injection, after 4-6 weeks and at months 3 and 6.

RESULTS

Intravitreal Pegaptanib was well tolerated and we had no complications. Mean visual acuity was 0.38 +/- 0.23 at baseline, after one month 0.38 +/- 0.26, at 3 months it was 0.39 +/- 0.22 and at 6 months 0.41 +/- 0.26. OCT examinations showed a decrease in central retinal thickness from 277 microm to 254 microm. In 91.4 % of the eyes the visual acuity was stabilised or improved. No patient had an elevated intraocular pressure after 6 months.

CONCLUSIONS

Intravitreal therapy with Pegaptanib was safe and effective. The majority of patients showed a stabilisation in all the assessed parameters. In clinical practice unselective VEGF inhibition should be considered carefully for patients with high cardiovascular risk profile or thromboembolic events in the history.

Kontinuierliche interscalenäre Plexusblockade bei einem dreijährigen Kind nach Armamputation - Ein Fallbericht

Amputations of extremities, especially in the childhood, impose high demands on the perioperative management. Apart from the intraoperative care of these children, the postoperative pain therapy has to do one's utmost in the avoidance of the development of phantom limb pain, which can, especially in the childhood, be associated with far reaching psychological consequences. We report the case of a 3-year old boy who had to undergo exarticualtion of his left arm due to an osteosarcoma of the humerus. The perioperative pain management was performed by a preoperatively placed interscalene catheter and infusion of 0.2 % ropivacaine. Within the first six days postoperatively complete pain relief could be ensured with this analgetic regimen.

Two different heat shock transcription factors regulate immediate early expression of stress genes in Arabidopsis

In order to assess the specific functional roles of different plant heat shock transcription factors (HSFs) we have isolated T-DNA insertion mutants in the AtHsf1 and AtHsf3 genes of Arabidopsis thaliana. Complete and selective loss of the promoter binding activities of AtHSF1 or AtHSF3, verified by immunoprecipitation assays, had no obvious effects on the heat shock (HS) response in the individual mutant lines. Only hsf1(-) /hsf3(-)double mutants were significantly impaired in HS gene expression. In these plants the inability to form high-molecular-weight HSE-binding complexes correlates with a dramatic change in the kinetics of mRNA accumulation from all HSF target genes tested, including members of the Hsp100, Hsp90, Hsp70 and small Hsp families, and genes for two heat-inducible class B-HSFs. After prolonged HS, the amounts of most heat shock mRNAs expressed, except transcripts of Hsp18.2, reached approximately the same levels as in wild type plants. Our data indicate that AtHSF1 and AtHSF3 are key regulators of the immediate stress-induced activation of HS gene transcription, and consequently determine the kinetics of the negative feed back loop that is responsible for the transience of HS gene expression in wild type.

Predicting blood-brain barrier permeability of drugs: evaluation of different in vitro assays

The ability of a drug to penetrate the blood-brain barrier (BBB) is essential for its use in the pharmaceutical treatment of CNS disorders. Five different in vitro methods to predict BBB permeability of drugs were compared and evaluated in the present study. All assays were performed with a consistent set of seven compounds and in the same physiological buffer to provide a basis for direct comparison of the results. Octanol-buffer and liposome-buffer partition coefficients were most conveniently obtained but failed to predict BBB permeability for certain drugs. The incorporation of drugs into lipid monolayers at the air-buffer interface was found to be a poor predictor of BBB permeability and was furthermore not considered suitable for screening due to the demanding experimental requirements. Permeability studies using Caco-2 cell monolayers provided a good correlation to an in vitro model of the BBB, which was based on primary cultured porcine brain capillary endothelial cells (PBCEC). However, differences in drug permeability between the intestine and brain derived cells were detected, limiting the advantages of the easy handling of the Caco-2 cell line compared to the more time-consuming primary culture of the BCEC.

Cell-type specific dendritic contacts between retinal ganglion cells during development

The extent of a neuron's dendritic field defines the region within which information is processed. The dendritic fields of functionally distinct ON and OFF center retinal ganglion cells (RGCs) form separate mosaics across the retina. Within each mosaic, neighboring dendritic fields overlap by a constant amount, sampling the visual field with the appropriate coverage. Contact-mediated lateral inhibition between neighboring RGCs has long been thought to regulate both the extent and overlap of dendritic fields during development. Here we show that dendro-dendritic contact exists between developing RGCs and occurs in a manner that would regulate the formation of ON and OFF mosaics separately. Dye-filled neighboring ON and OFF ferret alpha RGCs were reconstructed using multiphoton microscopy. At all neonatal ages examined, we observed dendro-dendritic contacts between RGCs of the same sign (ON/ON; OFF/OFF), but never between cells of opposite signs (ON/OFF). Terminal dendrites of one cell often touched a dendrite of its neighbor as they intersected. In some instances, the distal dendrite of one cell formed a fascicle with the proximal process of its neighbor. Alpha cells did not form contacts with neighboring beta cells of the same sign. Together, these observations suggest that dendro-dendritic contact between RGCs is cell-type specific. Dendritic contacts were observed even before the alpha cell arbors were completely stratified, suggesting that cell-cell recognition may take place early in their development. For each cell type, the relative overlap of dendritic fields was constant with age, despite a two-fold increase in field area. We suggest that dendro-dendritic contacts may be sites of intercellular signaling that could regulate local extension of dendrites to maintain the relative overlap of RGCs within a mosaic during development.

Progesterone receptor immunohistochemical quantitation compared with cytosolic assay: correlation with prognosis in breast cancer

Quantitation of estrogen and progesterone receptors (PR) represents the standard of care in the treatment of patients with breast cancer. Historically this was performed by cytosolic assay; current methods utilize immunohistochemical staining, which may be quantitated visually or by image cytometry. Formalin-fixed paraffin embedded sections from 95 breast carcinomas were immunostained with an avidin-biotin complex technique. steam antigen retrieval, and a monoclonal PR antibody (1/40 Biogenex). Nuclear immunostain was quantitated visually as the percentage of immunopositive nuclei, scored as 0 to 4. By image cytometry, the percentage of positively staining nuclear area (PPNA) was determined in 15 hpf using the CAS 200 Image Analyzer. Dextran-coated charcoal (DCC) ligand binding assay data were divided into negative (<10 fmol), low positive (10-50), or positive (>50). A statistically significant correlation was found between stage (P = 0.0001), the presence of nodal metastases (P = 0.0001), cytosolic assay (P = 0.036), image cytometry (P = 0.01), and disease-free survival. Only stage (P = 0.0001) and PR quantitation per cytosolic assay (P = 0.0001) correlated with overall survival. The method of choice for the assessment of PR hormone status in breast carcinomas is the DCC ligand binding assay. This method correlates with both survival and disease-free survival. Image cytometric quantitation of PR immunohistochemical staining correlates only with disease-free survival. The commonly used method of visual quantitation of PR immunostaining fails to relate either to survival or disease-free survival.

Human osteoblast-like cells phagocytose metal particles and express the macrophage marker CD68 in vitro

Periprosthetic osteolysis is a major cause of aseptic loosening in artificial joint replacement. It is assumed to occur in conjunction with the activation of macrophages. We have shown in vitro that human osteoblast-like cells, isolated from bone specimens obtained from patients undergoing hip replacement, phagocytose fine particles of titanium alloy (TiAlV). The human osteoblast-like cells were identified immunocytochemically by the presence of bone-specific alkaline phosphatase (BAP). With increasing duration of culture, a variable number of the osteoblastic cells became positive for the macrophage marker CD68, independent of the phagocytosis of particles, with a fine granular cytoplasmic staining which was coexpressed with BAP as revealed by immunodoublestaining. The metal particles were not toxic to the osteoblastic cells since even in culture for up to four weeks massively laden cells were vital and had a characteristic morphology. Cells of the human osteosarcoma cell line (HOS 58) were also able to phagocytose metal particles but had only a low expression of the CD68 antigen. Fluorescence-activated cell scanning confirmed our immunocytochemical results. Additionally, the cells were found to be negative for the major histocompatibility complex-II (MHC-II) which is a marker for macrophages and other antigen-presenting cells. Negative results of histochemical tests for tartrate-resistant acid phosphatase excluded the contamination by osteoclasts or macrophages in culture. Our observations suggest that the osteoblast can either change to a phagocytosing cell or that the phagocytosis is an underestimated property of the osteoblast. The detection of the CD68 antigen is insufficient to prove the monocytic lineage. In order to discriminate between macrophages and osteoblasts additional markers should be used. To our knowledge, this is the first demonstration of cells of an osteoblastic origin which have acquired a mixed phenotype of both osteoblasts and macrophages.

Axon regeneration in organotypic slice cultures from the mammalian auditory system is topographic and functional

In vitro models have frequently been employed to investigate the specificity of the formation of axonal projections during both development and regeneration. Such studies demonstrated pathway, target, and laminar specificity, yet they did not tackle the problem of topography. Here, we addressed the issue of regeneration of spatial specificity at the topographic level by lesioning a precisely organized projection from the auditory system of neonatal rats in organotypic slice culture and by analyzing regeneration capacity. Lesioning had no effect on the survival of axotomized neurons or the structure of the auditory nuclei. Anterograde and retrograde biocytin tracing demonstrated that the projection regenerated topographically at the supracellular level. Whole-cell patch-clamp recordings revealed that the regenerated projection was functional. Topographic regeneration was not impaired by blocking spike activity with tetrodotoxin or glycinergic transmission with strychnine. However, if lesioning was performed after the slices had been incubated for 1 week, regeneration capacity was lost despite good survival of neurons. The loss of the regeneration capacity in vitro occurs at a developmental stage that corresponds to the age when the capacity for axonal reorganization is lost in vivo. We conclude that the developmental processes occurring in vivo and in vitro are comparable in this system, which is why we think that essential aspects of the loss of regeneration capacity may be addressed with our culture model in the future.

Development of auditory brainstem circuitry. Activity-dependent and activity-independent processes

Despite its complexity, the neural circuitry in the auditory brainstem of vertebrates displays a fascinating amount of order. How is this order established in such a precise manner during ontogeny? In this review, we will summarize evidence for both activity-independent and activity-dependent processes involved in the generation of the auditory brainstem circuitry of birds and mammals. An example of activity-independent processes is the emergence of crude topography, which, most probably, is determined by molecular markers whose expression is genetically controlled. On the other hand, neuronal activity supports cell survival, affects dendritic and axonal growth, and influences fine tuning of maps. It appears that various types of neuronal activity, namely spontaneous versus acoustically evoked, bilateral versus unilateral, uncoordinated versus patterned, play a role during different aspects of development and cooperate with the activity-independent processes to ensure the proper formation of neuronal circuitry.

Development of glycinergic transmission in organotypic cultures from auditory brain stem

We investigated whether glycinergic transmission develops organotypically in auditory brain stem cultures. Slices of the medial nucleus of the trapezoid body and the lateral superior olive were incubated in medium with a raised extracellular K+ concentration. As in vivo, glycine receptor alpha1 subunit immunoreactivity increased and became clustered on somata and proximal dendrites. Together with organotypic expression of glycine transporter GLYT2, this indicates that molecular components of glycinergic synapses form properly. In contrast, glycinergic synaptic currents did not develop as in vivo: after 7 days in vitro they were still similar to those at the time of culture preparation. We suggest that for organotypic development of glycine receptors and transporters, Ca2+ influx due to elevated K+ is sufficient. The development of functional synaptic transmission, however, may require patterned electrical activity.

Development of a topographically organized auditory network in slice culture is calcium dependent

Inhibitory and excitatory connections of remarkably precise topographic order are characteristic features of the mammalian auditory system, particularly within the superior olivary complex (SOC). Little is known about the requirements for the correct development of these specific connections. Previous in vivo experiments have demonstrated a high expression of calcium-binding proteins in this system during development, pointing to the need for precise calcium regulation. Here, we have employed an organotypic slice culture from the above neuronal network and analyzed the requirements for the maintenance and development of this system in vitro. When slices from neonatal rats were incubated in standard culture medium for up to 7 days, we found no organotypic features. Only if 25 mM KCl was added to the culture medium, the cytoarchitecture of the nuclei, the neuronal morphology, and the specificity and topography of internuclear connections were indistinguishable from that in vivo. The addition of calcium channel blockers (MgCl2 and nifedipine) to the high-KCl medium reduced organotypicity drastically, indicating that a depolarization-induced increase of intracellular calcium is indispensable. Furthermore, the temporal course of the expression of the calcium-binding protein parvalbumin in culture under high KCl mimics that in vivo, demonstrating developmental processes during incubation. The need for calcium influx into neurons of this auditory network in vitro (which is not seen in other slice culture systems) strengthens the hypothesis that an optimal calcium concentration is exceptionally important in auditory neurons. The effect of KCl in the slice cultures may substitute for input activity regulating intracellular calcium in auditory neurons in vivo.

Distribution of the calcium-binding proteins parvalbumin and calretinin in the auditory brainstem of adult and developing rats

Parvalbumin (PV), calretinin (CR), and calbindin (CB) are calcium-binding proteins which are presumably involved in the regulation of the intracellular calcium concentration. Within the rat auditory system, CB is transiently expressed in several nuclei during the period of synapse refinement, indicating a specific function of CB during development, yet little is known in this regard about PV and CR. In order to gather more information about calcium-binding proteins during development, we analyzed the spatiotemporal distribution of PV and CR in the rat auditory brainstem using immunocytochemistry. In the adult, PV was heavily present in somata and neuropil of all nuclei and in fibers of all tracts. CR was found in somata of the cochlear nucleus and peripheral aspects of the inferior colliculus as well as in fibers extending into the superior olivary complex and the nuclei of the lateral lemniscus. The developmental expression of PV was characterized by a relatively late appearance in somata (at postnatal day 8), followed by a rapid increase to adult levels. In contrast, CR immunoreactivity was already strong two days before birth, yet the number and intensity of labeled neurons subsequently decreased and CR disappeared almost completely in the superior olivary complex, nuclei of the lateral lemniscus, and central aspects of the inferior colliculus. These data, together with those on CB, show that CR, CB, and PV are sequentially expressed during auditory brainstem development. They also suggest that the presence of the three proteins can be correlated with definite developmental stages.

Orientation and open-sea navigation in sea turtles

Loggerhead sea turtle hatchlings (Caretta caretta L.) emerge from underground nests, scramble to the sea and begin a transoceanic migration by swimming away from their natal beach and into the open ocean. Evidence suggests that hatchlings sequentially use three different sets of cues to maintain orientation during their initial migration offshore. While on the beach, hatchlings find the ocean by crawling towards the lower, brighter seaward horizon and away from the dark, elevated silhouettes of vegetation and dunes. Upon entering the ocean, turtles initially orient seawards by swimming into waves, which can be detected as orbital movements from under water. Laboratory experiments have demonstrated that turtles can transfer a course initiated on the basis of waves or visual cues to a course mediated by a magnetic compass. Thus, by setting a magnetic course on the basis of nearshore cues that indicate the seaward direction, hatchlings may continue on offshore headings after entering deep water beyond sight of land. Sea turtles may use the earth's magnetic field not only as a cue for compass orientation but also as a source of world-wide positional information. Recent experiments have demonstrated that loggerheads can detect subtle differences in magnetic field inclination and intensity, two geomagnetic features that vary across the surface of the earth. Because most nesting beaches and oceanic regions are marked by a unique combination of these features, these findings raise the possibility that adult sea turtles navigate using a bicoordinate magnetic map.

Role of echocardiography in the diagnosis of occult penetrating cardiac injury

OBJECTIVE

To determine the usefulness of early echocardiography in stable patients with penetrating wounds in proximity to the heart.

DESIGN

Retrospective chart review over a 1-year period.

SETTING

Urban level I trauma center.

PATIENTS

121 clinically stable patients with penetrating wounds in proximity to the heart underwent immediate echocardiography (ECHO). Those with evidence of pericardial effusion then underwent subxiphoid pericardial window (SPW), followed by a median sternotomy if blood was found.

RESULTS

Thirty patients had an ECHO that was positive and underwent immediate SPW. One patient with an initially negative ECHO deteriorated 5 hours after admission; a repeat ECHO was positive, and he also underwent SPW. In 16 of the 31 SPW performed, blood in the pericardial sac was confirmed. Of these 16, four had pericardial blood that cleared with irrigation and required no further intervention. The remaining 12 patients underwent exploration: 3 had injury to the pericardium only, 4 had injury to the right atrium, 3 had injury to the right ventricle, and 2 had injury to the left ventricle. All nine myocardial injuries required operative repair; all survived.

CONCLUSIONS

Using the protocol of early ECHO and selective pericardial window, no clinically significant injuries were missed. In all, 12 penetrating cardiac injuries were identified and repaired successfully. We have found early and aggressive work-up, as outlined herein, to be helpful in the successful treatment of occult cardiac injuries.