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Khurana L, Harczos T, Moser T, Jablonski L. En route to sound coding strategies for optical cochlear implants. iScience 2023; 26:107725. [PMID: 37720089 PMCID: PMC10502376 DOI: 10.1016/j.isci.2023.107725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2023] Open
Abstract
Hearing loss is the most common human sensory deficit. Severe-to-complete sensorineural hearing loss is often treated by electrical cochlear implants (eCIs) bypassing dysfunctional or lost hair cells by direct stimulation of the auditory nerve. The wide current spread from each intracochlear electrode array contact activates large sets of tonotopically organized neurons limiting spectral selectivity of sound coding. Despite many efforts, an increase in the number of independent eCI stimulation channels seems impossible to achieve. Light, which can be better confined in space than electric current may help optical cochlear implants (oCIs) to overcome eCI shortcomings. In this review, we present the current state of the optogenetic sound encoding. We highlight optical sound coding strategy development capitalizing on the optical stimulation that requires fine-grained, fast, and power-efficient real-time sound processing controlling dozens of microscale optical emitters as an emerging research area.
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Affiliation(s)
- Lakshay Khurana
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
- Auditory Neuroscience and Synaptic Nanophysiology Group, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- Junior Research Group “Computational Neuroscience and Neuroengineering”, Göttingen, Germany
- The Doctoral Program “Sensory and Motor Neuroscience”, Göttingen Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences (GGNB), Göttingen, Germany
- InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Tamas Harczos
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
- Auditory Neuroscience and Synaptic Nanophysiology Group, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Lukasz Jablonski
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
- Junior Research Group “Computational Neuroscience and Neuroengineering”, Göttingen, Germany
- InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
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Khurana L, Keppeler D, Jablonski L, Moser T. Model-based prediction of optogenetic sound encoding in the human cochlea by future optical cochlear implants. Comput Struct Biotechnol J 2022; 20:3621-3629. [PMID: 35860414 PMCID: PMC9283772 DOI: 10.1016/j.csbj.2022.06.061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/28/2022] [Accepted: 06/28/2022] [Indexed: 01/17/2023] Open
Abstract
When hearing fails, electrical cochlear implants (eCIs) partially restore hearing by direct stimulation of spiral ganglion neurons (SGNs). As light can be better confined in space than electrical current, optical CIs (oCIs) provide more spectral information promising a fundamental improvement of hearing restoration by cochlear implants. Here, we turned to computer modelling for predicting the outcome of optogenetic hearing restoration by future oCIs in humans. We combined three-dimensional reconstruction of the human cochlea with ray-tracing simulation of emission from LED or laser-coupled waveguide emitters of the oCI. Irradiance was read out at the somata of SGNs. The irradiance values reached with waveguides were about 14 times higher than with LEDs, at the same radiant flux of the emitter. Moreover, waveguides outperformed LEDs regarding spectral selectivity. oCIs with either emitter type showed greater spectral selectivity when compared to eCI. In addition, modeling the effects of the source-to-SGN distance, orientation of the sources and impact of scar tissue further informs the development of optogenetic hearing restoration.
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Affiliation(s)
- Lakshay Khurana
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany.,Auditory Neuroscience & Synaptic Nanophysiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Göttingen Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences (GGNB), University of Göttingen, Göttingen, Germany.,InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Daniel Keppeler
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience & Synaptic Nanophysiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Lukasz Jablonski
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany.,InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany.,Auditory Neuroscience & Synaptic Nanophysiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
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Keppeler D, Schwaerzle M, Harczos T, Jablonski L, Dieter A, Wolf B, Ayub S, Vogl C, Wrobel C, Hoch G, Abdellatif K, Jeschke M, Rankovic V, Paul O, Ruther P, Moser T. Multichannel optogenetic stimulation of the auditory pathway using microfabricated LED cochlear implants in rodents. Sci Transl Med 2021; 12:12/553/eabb8086. [PMID: 32718992 DOI: 10.1126/scitranslmed.abb8086] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/03/2020] [Indexed: 12/28/2022]
Abstract
When hearing fails, electrical cochlear implants (eCIs) provide the brain with auditory information. One important bottleneck of CIs is the poor spectral selectivity that results from the wide current spread from each of the electrode contacts. Optical CIs (oCIs) promise to make better use of the tonotopic order of spiral ganglion neurons (SGNs) inside the cochlea by spatially confined stimulation. Here, we established multichannel oCIs based on light-emitting diode (LED) arrays and used them for optical stimulation of channelrhodopsin (ChR)-expressing SGNs in rodents. Power-efficient blue LED chips were integrated onto microfabricated 15-μm-thin polyimide-based carriers comprising interconnecting lines to address individual LEDs by a stationary or mobile driver circuitry. We extensively characterized the optoelectronic, thermal, and mechanical properties of the oCIs and demonstrated stability over weeks in vitro. We then implanted the oCIs into ChR-expressing rats and gerbils, and characterized multichannel optogenetic SGN stimulation by electrophysiological and behavioral experiments. Improved spectral selectivity was directly demonstrated by recordings from the auditory midbrain. Long-term experiments in deafened ChR-expressing rats and in nontreated control animals demonstrated specificity of optogenetic stimulation. Behavioral studies on animals carrying a wireless oCI sound processor revealed auditory percepts. This study demonstrates hearing restoration with improved spectral selectivity by an LED-based multichannel oCI system.
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Affiliation(s)
- Daniel Keppeler
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.,Göttingen Graduate Center for Neurosciences and Molecular Biosciences, University of Göttingen, 37075 Göttingen, Germany
| | - Michael Schwaerzle
- University of Freiburg, Department of Microsystems Engineering (IMTEK), 79110 Freiburg, Germany.,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, 79110 Freiburg, Germany
| | - Tamas Harczos
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
| | - Lukasz Jablonski
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
| | - Alexander Dieter
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.,Göttingen Graduate Center for Neurosciences and Molecular Biosciences, University of Göttingen, 37075 Göttingen, Germany
| | - Bettina Wolf
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
| | - Suleman Ayub
- University of Freiburg, Department of Microsystems Engineering (IMTEK), 79110 Freiburg, Germany.,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, 79110 Freiburg, Germany
| | - Christian Vogl
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, 37075 Göttingen, Germany
| | - Christian Wrobel
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.,Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Center Göttingen, 37099 Göttingen, Germany
| | - Gerhard Hoch
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
| | - Khaled Abdellatif
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
| | - Marcus Jeschke
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
| | - Vladan Rankovic
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
| | - Oliver Paul
- University of Freiburg, Department of Microsystems Engineering (IMTEK), 79110 Freiburg, Germany.,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, 79110 Freiburg, Germany
| | - Patrick Ruther
- University of Freiburg, Department of Microsystems Engineering (IMTEK), 79110 Freiburg, Germany. .,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, 79110 Freiburg, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany. .,Göttingen Graduate Center for Neurosciences and Molecular Biosciences, University of Göttingen, 37075 Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, 37075 Göttingen, Germany.,Multiscale Bioimaging Cluster of Excellence, University Medical Center Göttingen, 37075 Göttingen, Germany.,MPI for Biophysical Chemistry, 37077 Göttingen, Germany
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Dieter A, Klein E, Keppeler D, Jablonski L, Harczos T, Hoch G, Rankovic V, Paul O, Jeschke M, Ruther P, Moser T. μLED-based optical cochlear implants for spectrally selective activation of the auditory nerve. EMBO Mol Med 2020; 12:e12387. [PMID: 32596983 PMCID: PMC7411546 DOI: 10.15252/emmm.202012387] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/23/2020] [Accepted: 06/02/2020] [Indexed: 01/19/2023] Open
Abstract
Electrical cochlear implants (eCIs) partially restore hearing and enable speech comprehension to more than half a million users, thereby re-connecting deaf patients to the auditory scene surrounding them. Yet, eCIs suffer from limited spectral selectivity, resulting from current spread around each electrode contact and causing poor speech recognition in the presence of background noise. Optogenetic stimulation of the auditory nerve might overcome this limitation as light can be conveniently confined in space. Here, we combined virus-mediated optogenetic manipulation of cochlear spiral ganglion neurons (SGNs) and microsystems engineering to establish acute multi-channel optical cochlear implant (oCI) stimulation in adult Mongolian gerbils. oCIs based on 16 microscale thin-film light-emitting diodes (μLEDs) evoked tonotopic activation of the auditory pathway with high spectral selectivity and modest power requirements in hearing and deaf gerbils. These results prove the feasibility of μLED-based oCIs for spectrally selective activation of the auditory nerve.
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Affiliation(s)
- Alexander Dieter
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Göttingen Graduate School for Neurosciences and Molecular BiosciencesUniversity of GöttingenGöttingenGermany
- Present address:
Synaptic Wiring LabCenter for Molecular Neurobiology HamburgUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Eric Klein
- Department of Microsystems Engineering (IMTEK)University of FreiburgFreiburgGermany
| | - Daniel Keppeler
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
| | - Lukasz Jablonski
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - Tamas Harczos
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - Gerhard Hoch
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - Vladan Rankovic
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
- Restorative Cochlear Genomics GroupAuditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - Oliver Paul
- Department of Microsystems Engineering (IMTEK)University of FreiburgFreiburgGermany
- BrainLinks‐BrainToolsCluster of ExcellenceUniversity of FreiburgFreiburgGermany
| | - Marcus Jeschke
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
- Cognitive Hearing in Primates GroupAuditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - Patrick Ruther
- Department of Microsystems Engineering (IMTEK)University of FreiburgFreiburgGermany
- BrainLinks‐BrainToolsCluster of ExcellenceUniversity of FreiburgFreiburgGermany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Göttingen Graduate School for Neurosciences and Molecular BiosciencesUniversity of GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
- Auditory Neuroscience GroupMax Planck Institute for Experimental MedicineGöttingenGermany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC)University of GoettingenGoettingenGermany
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Ritzau-Jost A, Jablonski L, Viotti J, Lipstein N, Eilers J, Hallermann S. Apparent calcium dependence of vesicle recruitment. J Physiol 2018; 596:4693-4707. [PMID: 29928766 DOI: 10.1113/jp275911] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 06/11/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Synaptic transmission relies on the recruitment of neurotransmitter-filled vesicles to presynaptic release sites. Increased intracellular calcium buffering slows the recovery from synaptic depression, suggesting that vesicle recruitment is a calcium-dependent process. However, the molecular mechanisms of vesicle recruitment have only been investigated at some synapses. We investigate the role of calcium in vesicle recruitment at the cerebellar mossy fibre to granule cell synapse. We find that increased intracellular calcium buffering slows the recovery from depression following physiological stimulation. However, the recovery is largely resistant to perturbation of the molecular pathways previously shown to mediate calcium-dependent vesicle recruitment. Furthermore, we find two pools of vesicles with different recruitment speeds and show that models incorporating two pools of vesicles with different calcium-independent recruitment rates can explain our data. In this framework, increased calcium buffering prevents the release of intrinsically fast-recruited vesicles but does not change the vesicle recruitment rates themselves. ABSTRACT During sustained synaptic transmission, recruitment of new transmitter-filled vesicles to the release site counteracts vesicle depletion and thus synaptic depression. An elevated intracellular Ca2+ concentration has been proposed to accelerate the rate of vesicle recruitment at many synapses. This conclusion is often based on the finding that increased intracellular Ca2+ buffering slows the recovery from synaptic depression. However, the molecular mechanisms of the activity-dependent acceleration of vesicle recruitment have only been analysed at some synapses. Using physiological stimulation patterns in postsynaptic recordings and step depolarizations in presynaptic bouton recordings, we investigate vesicle recruitment at cerebellar mossy fibre boutons. We show that increased intracellular Ca2+ buffering slows recovery from depression dramatically. However, pharmacological and genetic interference with calmodulin or the calmodulin-Munc13 pathway, which has been proposed to mediate Ca2+ -dependence of vesicle recruitment, barely affects vesicle recovery from depression. Furthermore, we show that cerebellar mossy fibre boutons have two pools of vesicles: rapidly fusing vesicles that recover slowly and slowly fusing vesicles that recover rapidly. Finally, models adopting such two pools of vesicles with Ca2+ -independent recruitment rates can explain the slowed recovery from depression upon increased Ca2+ buffering. Our data do not rule out the involvement of the calmodulin-Munc13 pathway during stronger stimuli or other molecular pathways mediating Ca2+ -dependent vesicle recruitment at cerebellar mossy fibre boutons. However, we show that well-established two-pool models predict an apparent Ca2+ -dependence of vesicle recruitment. Thus, previous conclusions of Ca2+ -dependent vesicle recruitment based solely on increased intracellular Ca2+ buffering should be considered with caution.
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Affiliation(s)
- Andreas Ritzau-Jost
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Lukasz Jablonski
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Julio Viotti
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany.,Department of Anatomy and Embryology, Center of Anatomy, University Medical Center Göttingen, Göttingen, Germany
| | - Noa Lipstein
- Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Jens Eilers
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Stefan Hallermann
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
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Albrecht R, Bochmann C, Süße A, Jablonski L, Settmacher U. [Hybrid NOS appendectomy (NA): clinical assessment of a new surgical technique]. Zentralbl Chir 2012; 138:449-55. [PMID: 23242604 DOI: 10.1055/s-0032-1327892] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
UNLABELLED INTRODUCTION, AIM AND METHOD: Consecutive female patients undergoing hybrid NOS appendectomy (NA - with prospectively collected data) and laparoscopic appendectomy (LA - with retrospectively registered data) were compared by means of a matched-pair analysis according to selected criteria such as patient age, BMI, ASA and previous operations showing a near-perfect congruence with the following aims to: 1) demonstrate the feasibility of NA and to estimate its general costs, and 2) elucidate the outcome of the two techniques using available perioperative parameters from daily clinical practice. In particular, operating time, complications, histopathological findings, postoperative hospital stay and analgesic scores were used for comparison. A gynaecological follow-up investigation was carried out on the day of discharge and after a medium-term time period of 4 weeks in the NA group, and 6 months postoperatively, patients of both groups were interviewed using a standardised questionnaire. RESULTS From 05/01/2008 to 02/28/2010, transvaginal NA (n = 30) was compared with the results of the conventional LA (n = 30) in 60 female patients with regard to the operative outcome. Overall, matched-pair analysis of LA with NA, the novel technique resulted in the assessment of basically comparable surgical procedures with regard to perioperative routine parameters and outcome. There were no intraoperative complications in either of the two approaches; conversion was not required in both techniques. In addition, there were no significant differences in operating time (p = 0.099), postoperative complications (p = 0.72) and analgesic scores (p = 0.33/0.46). Postoperative hospital stay was even slightly shorter in the NA group (p = 0.02). The costs of the two methods are almost identical if the same instruments are used. Patient interviews suggested a slightly faster recovery, greater satisfaction with the better cosmetic outcome as well as a reduced pain intensity in favour of transvaginal NA. CONCLUSION Provided that a well developed laparoscopic expertise exists, it turned out i) that there are no serious reasons to resist a quick inauguration and establishment of NA for selected cases as well as ii) even to facilitate further clinical distribution of NA. Further systematic data collection appears to be indicated to analyse long-term outcome as parameters of an appropriate quality assurance.
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Affiliation(s)
- R Albrecht
- Klinik für Viszeral- und Gefäßchirurgie, HELIOS Klinikum Aue, Deutschland.
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Schmiedel D, Vary PS, Jablonski L, Hillen W. Plasmids for efficient single-copy gene cloning into gdh2 and trpC of Bacillus megaterium DSM319 and QM B1551. Appl Microbiol Biotechnol 1997; 47:543-6. [PMID: 9210344 DOI: 10.1007/s002530050970] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We constructed integrative plasmids to place xylA-lacZ indicator gene fusions into two different loci of the Bacillus megaterium chromosome, gdh2 and trpC, in lac mutants of strains DSM 319 and QM B1551, which differ markedly. Single-crossover integration was achieved in all cases while double crossovers occurred only in gdh2 of DSM 319 and QM B1551 and in trpC of QM B1551. Neither of the loci affected regulation of the xylA-lacZ fusions. These results confirm the suitability of the two gene loci for single-copy cloning.
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Affiliation(s)
- D Schmiedel
- Lehrstuhl für Mikrobiologie, Universität Erlangen-Nürnberg, Germany
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Abstract
Conditions for electroporation of plasmid DNA into Pasteurella multocida were determined for use in developing a cloning system to study virulence factors of P. multocida. The highest efficiency of transformation (1.25 x 10(7) cfu/micrograms DNA) was obtained when 7.6 x 10(10) cells of P. multocida strain R473 were electroporated at 12.5 kV/cm (10 ms, 5 ng of pVM109). Transformation efficiencies of cells prepared at mid-log-phase were approximately 0.5 log10 lower than early, late, or stationary phases. Neither pBR322 nor pUC-19 were able to transform strain R473 under these conditions, even when DNA concentrations were increased to 1 microgram. When pBR322 was ligated with a Pasteurella plasmid, pLAR-1, the hybrid was able to transform strain R473 at an efficiency between 4.5 x 10(2) and 8 x 10(4) cfu/micrograms DNA. Six strains of P. multocida including serotypes A, B, D, and E were transformed successfully.
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Affiliation(s)
- L Jablonski
- Department of Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg 24061
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Szczygielska J, Modzelewska I, Blaszyńska M, Dolezko H, Wysocka-Jablońska M, Hencner Z, Jablonski L, Malczyńska E. [Virological and serological investigations in pneumo-adeno- and meningopathies in children]. Pol Tyg Lek 1966; 21:1957-9. [PMID: 5981418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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