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  • 1
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Neuromonitoring ; SSEP ; NIRS ; Transkonjunktivale Sauerstoffspannung ; Selektive Shunteinlage ; Key words NIRS ; Selective shunting ; Neuromonitoring ; SSEP ; Conjunctival oxygen tension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract The principle of, “selective shunting” during carotid endarterectomy requires a special concept to monitor neuronal function. The valence of the oxymetric methods, “near-infrared” spectroscopy (NIRS) and conjunctival oxygen tension (pcjO2) was determined with the reference method somatosensory evoked potentials (SEP). Methods. In 41 patients undergoing reconstructive surgery on the internal carotid artery, recordings of the different methods were obtained under control, during carotid occlusion and during reperfusion. Cerebral ischemia was assumed if a complete loss of SEP appeared and an intraluminal shunt was placed. Conjunctival oxygen tension was measured continuously and simultaneously on the ipsi- and contralateral eye. Results. In comparison to the reference method (SEP) the sensitivity and specificity of NIRS was 80% and 94%, respectively. The occlusion induced reduction of NIRS appeared 6.5±3.2 min earlier than the corresponding loss of SEP. Biocular determination of conjunctival oxygen tension was not able to detect hypoperfusion dependent ischemia during carotid occlusion. Conclusion. During carotid endarterectomy the measurement of conjunctival oxygen tension is not useful to detect cerebral ischemia. The use of NIRS as a single neuronal monitor is not appropriate to perform, “selective shunting”. In contrast to SEP, however, NIRS is characterized by its rapid changes immediately following carotid occlusion. This non invasive method is likely to complete the standard method SEP in a modified monitoring concept of neuronal function during carotid endarterectomy.
    Notes: Zusamenfassung Ziel der Arbeit. Das Prinzip der selektiven Shunteinlage bei Karotisendarterektomien erfordert ein differenziertes Neuromonitoringkonzept. Die Wertigkeit der oxymetrischen Verfahren “near-infrared” Spektroskopie (NIRS) sowie des transkonjunktivalen Sauerstoffpartialdrucks (pcjO2) wurden anhand der Referenzmethode SSEP bestimmt. Methodik. Bei 41 Patienten mit elektiver Karotis-TEA wurden diese Neuromonitoringparameter unter Kontrollbedingungen, während Karotisokklusion und in der Reperfusionsphase bestimmt. Der vollständige Verlust der SSEP-Amplitude war das Kriterium zur Shunteinlage. Die Messung des transkonjunktivalen Sauerstoffpartialdrucks erfolgte zeitgleich auf dem ipsi- und kontralateralen Auge. Ergebnisse. Im Vergleich zur Referenzmethode SSEP zeigte NIRS eine Sensitivität und Spezifität von 80% und 94%. Die okklusionsbedingte Reduktion von NIRS zeigte sich im Mittel 6,5±3,2 min früher als die entsprechenden Veränderungen der SSEP-Werte. Die biokulare Bestimmung des transkonjunktivalen Sauerstoffpartialdrucks konnte die hypoperfusionsbedingte Ischämie nicht detektieren. Schlußfolgerung. Die transkonjunktivale Sauerstoffspannung ist bei Karotisendarterektomien als Neuromonitoringverfahren ungeeignet. Die alleinige Indikation zur Shunteinlage ist mittels NIRS nicht möglich. NIRS ist jedoch im Unterschied zu den SSEP durch eine rasche Änderung nach Karotisokklusion charakterisiert. NIRS ist als nicht invasive Methode geeignet, das Standardverfahren SSEP in einem modifizierten Neuromonitoringkonzept zu ergänzen.
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  • 2
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Tagesklinik ; Anästhesie-Informations-Management-System (AIMS) ; Dokumentation ; Unvorhergesehene stationäre Aufnahme ; Ambulantes Operieren ; Keywords Day care unit ; Anesthesia information management system (AIMS) ; Documentation ; Unanticipated admission ; Ambulatory surgery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract From January 1997 until June 1999, the complete durations of stay of 3152 outpatients were entered into a computerized documentation system. The scope of the data entry went from patient admission to patient release. The objective was to determine the usefulness of the anaesthesia information management system (AIMS) in producing complete and high-quality documentation in the field of outpatient operations. Some aspects and results from routine work are presented here. Method. The system was installed in eight bedside computers, in addition to a further client connected to the existing AIMS via Ethernet. Patient medical courses were documented both preoperatively and postoperatively in outpatient bedsides until their discharge or admission. The online documentation software NarkoData (Version 4, Imeso GmbH, Hüttenberg, Germany) was used to document and store patient data in a database. This program contains all relevant information concerning the course of anaesthesia and outpatient duration of stay, including application of drugs, vital signs, observation times, and medical findings as well as the data sets of the German Society of Anaesthesiology and Intensive Care Medicine (DGAI), ICD, and ICPM. Data was analyzed by exporting from the database into a statistical program using “structured query language.” Results. Data sets of 3152 outpatients were entered into the online documentation software. Most (54.2%) of the ambulatory surgical procedures were performed by the Department of Traumatology. General Surgery followed with 16.0%, and Urology managed 9.5% of the cases. The most frequent ambulatory surgical procedures were: diagnostic arthroscopy (923, 31.2%), removal of osteosynthetic material (410, 13.8%), and circumcision (250, 8.4%). Anesthesia procedures consisted of inhalative (38.6%, n=1218) and intravenous anesthesia (IVA) (29.9%, n=938). In 22.6% (713) of the cases, regional anaesthesia was performed. The average postoperative observation time was 289.2±140.1 minutes. One hundred sixty-nine patients (5.4%) were unexpectedly admitted to overnight care. The decision to admit patients to normal wards took place within the first 3 postoperative hours in 51.9% of the cases. Conclusion. The AIMS described above is sufficient in documenting the entire care process of patients in a day care unit. Integration into the existing AIMS was an important prerequisite for the integrity of the documentation chain. This allowed for a sensitive communication with other clinical data processing systems. The quality of documentation and flow of information at the workplaces in the day care unit were increased, similarly to other anaesthesiological workplaces in the hospital. Medical and administrative data and information for analyses of clinical processes are possible with such tools.
    Notes: Zusammenfassung Von Januar 1997 bis Juni 1999 wurde der komplette Aufenthalt aller tageschirurgischen Patienten, von der Aufnahme bis zur Entlassung, mit einem computergestützten Dokumentationssystem erfasst. Einzelne Aspekte und Ergebnisse aus dem Routinebetrieb sollen mit der Fragestellung vorgestellt werden, ob ein Anästhesie-Informations-Management-System (AIMS) geeignet ist, auch im Bereich des “Ambulanten Operierens” eine umfassende und qualitativ hochwertige Dokumentation zu gewährleisten. Methodik. Die Installation des Systems erfolgte durch Einbindung von 8 Bettplatz-Computern und eines weiteren Clients über das Intranet in das bestehende AIMS. An den tagesstationären Bettplätzen wurden Patientendaten prä- und postoperativ bis zur Entlassung oder Verlegung der Patienten mit der Online-Dokumentationssoftware NarkoData® Version 4 (Imeso GmbH, Hüttenberg) dokumentiert und in einer Datenbank gespeichert. Dieses Programm erfasst sämtliche für den Narkoseverlauf und tagesstationären Aufenthalt relevanten Informationen, u. a. Medikamentenapplikationen, Vitaldaten, Überwachungszeiten, Befunde sowie den Kerndatensatz der DGAI, ICD 9 und ICPM. Zur Auswertung wurden die Daten mittels der “Structured Query Language” (SQL) aus der Datenbank in ein Statistikprogramm exportiert. Ergebnisse. Die Datensätze von 3.152 tagesstationären Patienten wurden mit der Online-Dokumentationssoftware erfasst. Die häufigsten tageschirurgischen Operationen führte mit 54,2% der Fälle die operierende Fachabteilung Unfallchirurgie durch, gefolgt von der Allgemeinchirurgie mit 16,0% und der Urologie mit 9,5%. Die häufigsten tageschirurgischen Eingriffe waren diagnostische Arthroskopie (923, 31,2%), Entfernung von Osteosynthesematerial (410, 13,8%) und die Zirkumzision (250, 8,4%). Von anästhesiologischer Seite kamen zumeist die Inhalationsnarkose (38,6%, n=1218) und die intravenöse Anästhesie (IVA; 29,9%, n=938) zum Einsatz. Eine Regionalanästhesie wurde in 22,6% der Fälle (n=713) durchgeführt. Die durchschnittliche postoperative Überwachungszeit betrug 289,2±140,1 min. 169 Patienten (5,4%) wurden ungeplant stationär aufgenommen. Die Entscheidung zu einer stationären Aufnahme wurde bei 50,9% der stationär aufgenommenen Patienten intraoperativ oder in den ersten drei postoperativen Stunden gefällt. Schlussfolgerung. Das beschriebene AIMS ist geeignet, den gesamten Behandlungsprozess eines Patienten in einer operativen Tagesklinik zu dokumentieren. Die Integration in das bestehende System stellte sich als wesentliche Voraussetzung für die Integrität der Dokumentationskette heraus und ermöglicht eine sinnvolle Kommunikation mit anderen klinischen Datenverarbeitungssystemen. Wie auch im Bereich der Anästhesie konnten die Dokumentationsqualität und der Informationsfluss am Narkosearbeitsplatz gesteigert werden. Neben medizinischen und administrativen Daten stehen Informationen für die Analyse klinischer Prozesse zur Verfügung.
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  • 3
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: To investigate whether free melatonin may be better suited to reveal age-related changes, we studied the circadian rhythm alterations in saliva melatonin levels during aging. Special attention was paid to the question as to how the free melatonin rhythms change in aging and when such changes take place. A total of 52 healthy volunteers participated in the study consisting of young, middle-aged, old and the oldest groups. In each subject, a total of 12 time-point salivary melatonin samples was taken over 24 hr. Of the 52 data sets, 51 exhibited significant circadian rhythm over 24 hr by using the base cosine function analysis to fit the data. A clear circadian rhythm of salivary melatonin was present in all age groups. The decline in nocturnal peak levels (amplitude) in salivary melatonin was found in old and the oldest subjects. Both the old and the oldest subjects showed an increased daytime (baseline) melatonin levels. The off-set melatonin levels were more than two times higher in the oldest group than that in the other groups indicating a delayed phase of salivary melatonin. Most strikingly, we found that a step-wise decrease in the circadian rhythms of saliva melatonin occurred early in life, around 40 yr of ages. The middle-aged subjects had only 60% of the amplitude of the young subjects. In addition, the middle-aged subjects showed the longest peak levels duration and the lowest daytime melatonin levels. The present study showed that the alterations in the circadian rhythms of salivary melatonin begin during middle-age. Our results showed that salivary melatonin measurement is a reliable, sensitive and easy method to monitor changes in the circadian rhythms of melatonin during the course of aging.
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  • 4
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Neuropathology is the most reliable criterion for diagnosing Alzheimer's disease (AD). A well-established system for staging the spread of neuropathological changes in AD is available. The clinical use of a biomarker that reflects the neuropathological change occurring in brain tissue has not yet been established. Melatonin is a product that plays not only a major role in the regulation of the circadian rhythms but may also exert neuroprotective effects in AD. Melatonin levels were determined in ventricular postmortem cerebrospinal fluid (CSF) of 121 subjects. Braak staging and a modified Braak staging for cortex (MBSC) were used to evaluate the severity of AD neuropathology. The present study revealed that not only the Braak stages of AD, but also the MBSC were negatively correlated with CSF melatonin levels. By using MBSC, we now demonstrate for the first time that CSF melatonin levels were significantly decreased in the aged individuals with early neuropathological changes in the temporal cortex, where the AD process starts. Those individuals that did not have any neurofibrillary tangle (NFT) or neuritic plaque (NP) in the temporal cortex, had much higher melatonin levels (287 ± 68 and 280 ± 64 pg/mL, respectively) than those individuals that had a few NFTs and NPs (82 ± 4 and 39 ± 8 pg/mL, respectively) in the temporal cortex. These results suggest that the decrease in CSF melatonin levels may be an early event in the development of AD possibly occurring even before the clinical symptoms.
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  • 5
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Most odours are complex mixtures. However, the capacities of olfactory sensory neurons (OSNs) to process complex odour stimuli have never been explored in air-breathing vertebrates. To face this issue, the present study compares the electrical responses of single OSNs to two odour molecules, delivered singly and mixed together, in rats in vivo. This work is the first aimed at demonstrating that single OSNs simultaneously integrate several chemical signals and which, furthermore, attempts to describe such processes for the whole concentration range over which single OSNs can work. The results stress that complex interactions occur between components in odour mixtures and that OSN responses to such mixtures are not simply predictable from the responses to their components. Three types of interactions are described. They are termed suppression, hypoadditivity and synergy, in accord with psychophysical terminology. This allows us to draw links between peripheral odour reception and central odour coding. Indeed, events occurring in single OSNs may account for the dominating or even the masking effects of odour molecules in complex mixtures, i.e. for the prevailing action of a minor component in the final qualitative perception of a mixture. We conclude that our observations with binary mixtures anticipate the complexity of processes which may rise at the level of a single OSN in physiological conditions. Following this hypothesis, a natural odour would induce a multi-chemical integration at the level of single OSNs which may result in refining their individual odour-coding properties, leading them to play a crucial role in the final performance of the olfactory system.
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  • 6
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract A study on the development of a process to form materials suitable for biomedical xenograft implants from bovine cancellous bone is presented. Bone cubes cut from the condyle portion of bovine femurs sourced from abattoir waste were subjected to a defatting and subsequent deproteination procedure to produce shape-modifiable materials in which the biocompatible mineral calcium hydroxycarbonate apatite component was preserved in the original osseous architecture of the bovine bone. Optimum defatting was achieved by (1) thawing of the precut bone cubes in water, (2) pressure cooking at 15 psi in water, (3) soaking in 0.1 mol l−1 NaOH followed by a thorough rinse under running water, (4) microwave heating of the bone cubes in water, (5) refluxing in methyl acetate and finally (6) removal of internal liquid from the cubes by shaking and then air drying. Subsequent deproteination of the defatted bone cubes was optimally achieved by (1) soaking in 5% sodium hypochlorite solution at ambient temperature using ultrasonication, (2) thorough rinsing of the cubes in water followed by drying. The final product is a defatted/deproteinated, bleached material that can be molded into various shapes for implant use in the body. The bone specimens were characterized by a suite of analytical techniques (i.e. infrared, 31P and 13C solid magic-angle spinning (MAS) nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopies, atomic absorption (AA) spectrometry, inductively coupled plasma (ICP) spectrometry, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM)) in order to follow compositional changes during the various stages of processing. In general, bovine condyles proved to be the best source of xenograft materials with condyles from other animal species (i.e. deer, sheep and ostrich) being too small to constitute a utilizable source of cancellous bone. This study shows how value can be added to a hitherto underutilized abattoir by-product by using simple processing techniques.
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  • 7
    ISSN: 1573-4846
    Keywords: morphology ; electrical properties ; transparent conductive coatings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Tranparent conducting coatings have been prepared by sol gel methods either by a conventional sol-gel process (Antimony doped Tin Oxide—ATO, Aluminium doped Zinc Oxide—AZO) or a new wet chemical process using fully dispersed crystalline nanoparticles (ATO, Indium Tin Oxide—ITO). The dip coating technique has been used as deposition technique with single coating thickness varying from a few nanometer to ca. 400 nm. The layers have been fired in a furnace. Structural properties have been determined by x-ray diffraction and TEM analysis and the electrical properties by the van der Pauw/Hall measurement. Three different coating procedures have been used to investigate the effect on the structure, morphology and the electrical properties of the coatings. It is shown that the individual layer thickness in multilayer coatings influences dramatically the mentioned properties. Very thin individual layers favour a heterogeneous nucleation with dense columnar growth of the crystallites leading to low electrical resistivity (ρ ≈ 10−3Ω cm), while thick individual layers result in a porous morphology made of small crystallites leading to resistivities in the 10−2Ω cm range.
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