A Model-Based Product Evaluation Protocol for Comparison of Safety-Engineered Protection Mechanisms of Winged Blood Collection Needles.

OBJECTIVE: To evaluate differences in product characteristics and user preferences of safety-engineered protection mechanisms of winged blood collection needles. DESIGN: Randomized model-based simulation study. SETTING: University medical center. PARTICIPANTS: A total of 33 third-year medical students. METHODS: Venipuncture was performed using winged blood collection needles with 4 different safety mechanisms: (a) Venofix Safety, (b) BD Vacutainer Push Button, (c) Safety-Multifly, and (d) Surshield Surflo. Each needle type was used in 3 consecutive tries: there was an uninstructed first handling, then instructions were given according to the operating manual; subsequently, a first trial and second trial were conducted. Study end points included successful activation, activation time, single-handed activation, correct activation, possible risk of needlestick injury, possibility of deactivation, and preferred safety mechanism. RESULTS: The overall successful activation rate during the second trial was equal for all 4 devices (94%-100%). Median activation time was (a) 7 s, (b) 2 s, (c) 9 s, and (d) 7 s. Single-handed activation during the second trial was (a) 18%, (b) 82%, (c) 15%, and (d) 45%. Correct activation during the second trial was (a) 3%, (b) 64%, (c) 15%, and (d) 39%. Possible risk of needlestick injury during the second trial was highest with (d). Possibility of deactivation was (a) 0%, (b) 12%, (c) 9%, and (d) 18%. Individual preferences for each system were (a) 11, (b) 17, (c) 5, and (d) 0. The main reason for preference was the comprehensive safety mechanism. CONCLUSION: Significant differences exist between safety mechanisms of winged blood collection needles.

Healthcare utilization of people with type 2 diabetes in Germany: an analysis based on health insurance data.

AIMS: This population-based study assesses the healthcare utilization of people with Type 2 diabetes by analysing routine data from Allgemeine Orts-Krankenkasse (AOK), the largest statutory health insurance provider in Germany. METHODS: Anonymized billing data from all AOK-insured persons with at least one day of insurance during the evaluation year 2010 were analysed. Treatment and cost data from all areas of inpatient and outpatient care were available, as was information regarding patient age and sex. International Classification of Diseases (ICD-10) diagnosis and Anatomical Therapeutic Chemical (ATC) classification were used to identify 2.7 million insured persons with diabetes. RESULTS: The age- and sex-standardized prevalence of Type 2 diabetes was 9.8%. Of those patients identified, 33.9% had at least one diabetes-related complication and 83.0% had a diagnosis of hypertension. Almost two-thirds (63.1%) received antihyperglycaemic medication. Metformin and sulfonylurea were prescribed most often; medications without proof of benefit in endpoint studies were prescribed much less frequently. People without diabetes were admitted to hospital only half as often as those with Type 2 diabetes. The projected total expenditure in Germany for all people with Type 2 diabetes amounted to approximately €33.3 billion in 2010. CONCLUSIONS: This study shows an increase in both the prevalence of diabetes and treatment costs. The majority of people with Type 2 diabetes were aged 70 years or older. One third of this group has diabetes-related complications. Antihyperglycaemic medications without proof of benefit in endpoint studies were prescribed much less frequently than drugs with proof of benefit.

Electrical high frequency stimulation of the caudate nucleus induces local GABA outflow in freely moving rats.

Electrical high frequency stimulation of the globus pallidus internus or the subthalamic nucleus has beneficial motor effects in advanced Parkinson's disease. The mechanisms underlying these clinical results remain, however, unclear. From previous in vitro studies it is proposed that the gamma-aminobutyric acid (GABA) system is involved in the effectiveness of electrical high frequency stimulation (HFS). In these experiments, we developed an in vivo model that allows for simultaneous and collocated microdialysis and HFS by electrical pulses of 124 Hz in the caudate nucleus of freely moving rats. GABA and glutamate outflow were sampled by microdialysis technique and quantified after pre-column o-phthaldialdehyde sulphite derivatization using HPLC with electrochemical detection. As the most outstanding result, we could demonstrate that high frequency stimulation significantly increased basal GABA outflow without affecting glutamate levels in freely moving rats.

Temporal profile of connexin 43 expression after photothrombotic lesion in rat brain.

Following focal ischemic injury, several mechanisms lead to secondary expansion of the affected area and therefore increase the initial damage. We thoroughly investigated the expression of astrocytic connexin 43 (Cx43) after photothrombosis in rat brain. The temporal profile of Cx43 mRNA as well as protein expression was studied in remote, structurally uninjured cortical and hippocampal areas. The hippocampal formation revealed an increased number of Cx43 mRNA positive astrocytes and an up-regulated protein expression exclusively in the ipsilateral stratum oriens. We assume a participation of this region in glia scar formation. While Cx43 mRNA positive cells were transiently increased, immunoreactivity was reduced in the somatosensory cortex of injured hemispheres. The observed decrease of Cx43 protein in the post-ischemic cerebral cortex implies an impairment of gap junctional intercellular communication which might be detrimental to the brain.

Intraoperative computed tomography in otorhinolaryngology.

CONCLUSIONS: Intraoperative CT surgery provides the surgeon with additional information about the altered surgical site in difficult anatomical situations. The skull base and lamina papyracea may be revealed by means of intraoperative CT, which may be beneficial in endonasal sinus surgery involving difficult surgical sites, although individual ethmoid cells cannot be assessed owing to blood artefacts. This provides the surgeon with valuable information that may facilitate the procedure considerably. In soft-tissue surgery it is advisable to apply a contrast agent in order to achieve good soft-tissue contrast, thus allowing the tumour to be adequately distinguished from benign tissue. The intraoperative application of CT is a fairly time-consuming procedure, partly owing to the preparation time (set-up of the appliance; 10-min warming-up phase) and partly due to the length of time required to calculate each image (15 s). OBJECTIVE: CT is a well-established imaging method for the assessment of osseous and soft-tissue structures in the head and neck region. Saving information and transferring it to the intraoperative site may, however, be problematic. Computer-assisted navigation systems are now able to assist difficult surgical procedures in the field of otolaryngology. To investigate the indications for intraoperative CT, we used it in various surgical procedures in the head and neck region. MATERIAL AND METHODS: Intraoperative CT was applied using the Tomoscan M in 46 cases in order to demonstrate the surgical benefit of the following procedures: endonasal surgical procedures on the paranasal sinuses (maxillary and ethmoidal sinusitis, anterior fracture of the sphenoidal sinus); tumour removal by means of laser surgery (carcinomas of the hypopharynx and larynx); and cochlear implantation (to verify the electrode position). After positioning the patient on the CT table, the workstation was set up in the operating theatre. If necessary, the gantry could be moved over the patient's head without repositioning the patient. RESULTS: Intraoperative CT was used to assist in the exposure of the skull base and lamina papyracea in endonasal surgery of the paranasal sinuses. Individual ethmoidal sinuses could not be evaluated owing to blood artefacts. Intraoperative imaging proved particularly helpful in revision surgery for chronic sinusitis in cases with missing anatomical landmarks owing to previous surgeries, where there is an increased risk of inflicting damage to the skull base or orbita. The resection margins can be determined in craniofacial resections. In soft-tissue procedures, such as tumour removal by means of laser surgery, it proved possible to visualize the resection borders of malignant tumours. Assessment of the electrode position in cochlear implantation is particularly useful in revision cases and in cases of cochlear obliteration.

A comparison of two types of free bone grafts as transport discs in segmental distraction for reconstruction of calvarial bone defects: an experimental study.

INTRODUCTION: Several investigations over the past few years have shown that the importance of preserving the blood supply of the transport disc during segmental distraction has been overestimated. It was clearly demonstrated that distraction osteogenesis by local bone transportation could be achieved even with free bone grafts. So far, there have been no systematic investigations into how different types of free bone grafts vary in their function and suitability as transport discs in segmental craniofacial distraction. The aim of this study was to develop criteria to aid the clinician in selecting the most suitable free bone graft for distraction purposes. MATERIALS AND METHODS: Under general anesthesia, calvarial defects measuring 6 x 5 cm were created in 12 adult black head sheep in order to reconstruct them by segmental distraction using two different types of bone grafts as transport discs. Group 1 (n=6) received autotopical membranous bone of the calvarium as the transport segment, while group 2 (n=6) received heterotopical enchondral material from the iliac crest. Distraction was started postoperatively after 5 days at 0.6 mm/day and continued for 7 weeks. After a further 6 weeks of consolidation, the animals were killed and specimens examined macroscopically, radiographically and histologically. RESULTS: The significantly better quality of bone regenerates of group 1 was clearly influenced by the significantly better stability of the transport disc's connection to the distraction device, the calvaria grafts showing better volume stability and better mechanical resistance during transport than the iliac bone. The influence of both types of bone grafts on the macro- and microstructure of the newly formed bone was clearly evident. The mineralization density of group 2 regenerates was significantly lower than that of group 1 specimens. CONCLUSION: High mechanical stability of the bone graft is a very important point to consider when selecting a free graft for use as transport disc in local bone transport, especially if transport is necessary over long distances.

GABA neurons survive focal ischemic injury.

Focal cerebral lesions in rat brain induced by photothrombosis lead to an impaired inhibitory neurotransmission. A reduced gamma-aminobutyric acid (GABA)-mediated inhibition has been revealed by electrophysiological recordings associated with a diminished immunostaining of GABA handling proteins. Changes were found in ipsi- as well as in contralateral brain areas. Inhibition is mediated by interneurons using GABA as neurotransmitter. These cells use GAD (glutamate decarboxylase) to synthesize GABA. To analyze the vulnerability of GABAergic neurons in rats with a lesioned hindlimb area, cells expressing GAD65/67 mRNA were labeled using in situ hybridization. Positive somata were counted 7 and 30 days after focal ischemia in different cortical (hindlimb cortex, frontal cortex, primary and secondary somatosensory cortex) and hippocampal subsectors (pyramidal cell layer, stratum oriens and stratum radiatum/lacunosum-moleculare). The lesioned hemispheres were compared with the intact brain sides and with control brains. GABAergic interneurons survived the injury for up to 30 days in all investigated brain regions. Therefore it is unlikely that a loss of GABAergic neurons contributes to the reduced inhibition.

Intravascular stent placement for a fusiform aneurysm of the posterior cerebral artery: case report.

This article presents the case of a 45-year-old woman with a fusiform, broad-based, actually ruptured aneurysm of the posterior cerebral artery. The patient was successfully treated with stent placement and follow-up angiography demonstrated occlusion of the dome and the body of the aneurysm. Due to the limited neurosurgical treatment options, stent placement should be considered in patients with fusiform aneurysm of the posterior cerebral artery aneurysms.

Navigation with the StealthStationtrade mark in Skull Base Surgery: An Otolaryngological Perspective.

The introduction of computer-assisted navigation systems has played a significant role in assuring the integration and consistent intraoperative use of radiological information. We used a frameless stereotactic navigation system to treat 62 patients with a variety of skull base pathologies. The optoelectric appliance uses digital imaging information to locate surgical instruments in the operative area. The aim of this study was to evaluate the clinical accuracy, practicality, and impact of this navigation system on otolaryngological procedures. In conjunction with rigid head fixation and bone-anchored registration markers, the precision of registration was 0.8 mm and the accuracy of clinical measurements was less than 2 mm. With conventional fiducials and flexible head positioning, deviations were as large as 4.5 mm. The additional use of surface registration increased the precision of registration. Preoperative preparations took 15 to 35 minutes, depending on the complexity of the planning. Intraoperative computer support is an important aid to a surgeon's orientation, especially when a patient's anatomy is atypical. Navigation systems will likely improve the quality of surgery and facilitate training.

[Skull base surgery with an opto-electronic navigation system]. / Schädelbasischirurgie mit einem optoelektrischen Navigationssystem.

BACKGROUND AND OBJECTIVE: The exact localization of pathological anatomy is the basis of a successful operation. Malformations, tumors, or previous operations can make intraoperative orientation considerably more difficult. Navigation systems can be useful tools in such cases. METHODS: The OTS is an optoelectrical navigation system which was used on 34 patients with disorders of the skull base region. Clinical accuracy, practicability, and intraoperative usefulness of the system were evaluated. RESULTS: In clinical use, an accuracy of approximately 1.5 mm could only be achieved with the use of head fixation and bone-anchored reference markers. When using the VBH mouthpiece for dynamic referencing with flexible head positioning, deviations of less than 2 mm were observed. The preoperative preparation time was 15-25 min, depending on the operation schedule. CONCLUSIONS: The intraoperative orientation system represents a significant aid for orientation, particularly where anatomical alterations are present. Further modifications to improve both accuracy and the integration of the system into working practice are, however, essential.

Image-guided surgery of the anterior skull base.

Minimally invasive surgical procedures have revolutionized surgery of the paranasal sinuses. The endonasal procedure has become standard practice due to a better understanding of pathological physiology. However, malformations, previous operations and bleeding can interfere greatly with intraoperative orientation. Together with microscopy and endoscopy, image-guided surgery has the potential to be of significant assistance to the surgeon. We evaluated the electromagnetic navigation system InstaTrak 2000 (Visualization Technologies Inc., Lawrence, MA) in 168 patients with various disorders of the paranasal sinuses who underwent endonasal surgery. The system consists of a headset attached to an electronic transmitter which is fitted on the dorsum of the nose and in the external auditory canal. With the aid of low-frequency magnetic fields the position of the instrument equipped with an electromagnetic receiver is calculated on the basis of the reaction of ferromagnetic components in the magnetic field; the location is displayed in orthogonal sections on a high resolution screen. The intraoperative accuracy of the system was estimated to be 1.2-2.8 mm. The preparation time amounted to < 10 min. No system failures were observed. The InstaTrak 2000 navigation system is only suitable for endonasal surgery. The placement of the electromagnetic transmitter and receiver allows flexible head positioning through the use of a headset. This system is a valuable aid for the surgeon under anatomically complex conditions. The technology also lends itself well to training purposes, as visualization in different sectional planes augments the understanding of anatomy and pathological anatomy.

In-plane motion correction for MR spectroscopic imaging.

A motion-detection method is described that is specifically suited for MR spectroscopic imaging (MRSI) studies. Information on in-plane rotation and translation of the subject was obtained using external spatial reference markers that are uniquely identified via their chemical shift. The marker locations were obtained directly from the acquired data at each encoding step, and no additional data acquisition was required. This method was applied to brain 1H MRSI studies that include subcutaneous lipid signals, which otherwise result in enhanced sensitivity to subject motion.

Computer-generated microcooled reflection holograms in silicon for material processing with a CO(2) laser.

We report on the design, fabrication, and testing of multilevel computer-generated reflection holograms in Si for CO(2) laser material processing for laser intensities of <2 kW/cm(2). The holograms are designed with an iterative method based on scalar diffraction theory. In this case the reconstructed intensity distribution is independent of the incident high-power laser mode. For achieving high diffraction efficiencies, multilevel staircase surface topologies are fabricated by multimask and reactive ion-etching technology on the front side of a polished Si wafer. For efficient hologram cooling, a gratinglike structure of microchannels is chemically etched on the back side of the Si wafer. Absorption and deformation measurements have been carried out on both a microcooled flat mirror and a reflection hologram. The maximum deformation amounts to 200 nm and is 10 times smaller than comparable conventional uncoated Cu mirrors. A diffraction efficiency of 88% is achieved with an eight-level reflection hologram and a 30-mm-diameter CO(2) laser beam with a power of 5 kW.

Removal of lipid artifacts in 1H spectroscopic imaging by data extrapolation.

Proton MR spectroscopic imaging (MRSI) of human cerebral cortex is complicated by the presence of an intense signal from subcutaneous lipids, which, if not suppressed before Fourier reconstruction, causes ringing and signal contamination throughout the metabolite images as a result of limited k-space sampling. In this article, an improved reconstruction of the lipid region is obtained using the Papoulis-Gerchberg algorithm. This procedure makes use of the narrow-band-limited nature of the subcutaneous lipid signal to extrapolate to higher k-space values without alteration of the metabolite signal region. Using computer simulations and in vivo experimental studies, the implementation and performance of this algorithm were examined. This method was found to permit MRSI brain spectra to be obtained without applying any lipid suppression during data acquisition, at echo times of 50 ms and longer. When applied together with optimized acquisition methods, this provides an effective procedure for imaging metabolite distributions in cerebral cortical surface regions.

Intracranial germ-cell tumours--treatment results and residuals.

UNLABELLED: There is only sparse information about the development of children after successful treatment for intracranial germ-cell tumours. Between January 1981 and June 1992, 26 children with intracranial germ-cell tumours were treated in the University Hospital Hamburg-Eppendorf. We report on treatment results, long standing residuals and the "quality of life" of these patients. The long-term event-free survival was 88% for the germinomas and 43% for the malignant teratomas. Of the patients 58% had no relevant functional neurological deficits and 37% had mild impairment. Only 1 patient with metastatic disease was severely handicapped. Six patients showed neuro-endocrine dysfunction. All of them had suprasellar/hypothalamic lesions and all received successful substitution therapy. As to neuropsychological functions, 53% of the patients had no or only mild disturbances. The most affected function was speed of information processing. Of the children 69% were able to proceed with their education at the same level as before therapy. The overall self-assessment revealed good results in 75% of the patients. CONCLUSION: After surgical removal and radiation therapy long-term survival of intracranial germinomas amounts to 88%. Despite craniospinal axis radiation severe residuals are rare and a good quality of life is common. In malignant teratomas treatment regimens including chemotherapy are much less successful.

[Tumors of the cerebral hemispheres in children and adolescents. Results of treatment, residual syndromes and focal epilepsy]. / Grosshirnhemisphärentumoren bei Kindern und Jugendlichen. Behandlungsergebnisse, Residualsyndrome und fokale Epilepsien.

Tumors of the cerebral hemispheres comprise a big variety of histologic tumor types. Therefore, in the literature usually only specific subgroups such as benign gliomas and temporal lobe tumors are reported. In this study we report on 44 tumors of the cerebral hemispheres, including 9 angiomas. Apart from the treatment results concerning event free survival, the neurological and neuropsychological outcome of the patients were assessed. A peculiarity in the hemispheric tumors is their association with focal epilepsies. In 94% of our patient series, epileptic seizures had been the first tumor associated symptom and approximately 62% developed focal epilepsy. Seizure types, their association with tumor location and histology, the success of tumor therapy in concern of the epilepsy and the significance of the electroencephalogram in the follow up care of these patients were assessed separately.

Resolution and intensity distribution of output images reconstructed by sampled computer-generated holograms.

We address reconstruction abilities of computer-generated holograms that are fabricated in a sampled form and designed for spherical-wave illumination. Our approach enables one to define the limit of resolution of the object reconstruction and the light-intensity distribution in an output plane. The analysis takes into account a hologram aperture, a sampling aperture, and a curvature radius of spherical illumination. Theoretical results are confirmed by experimental verification.

[Mycotoxins as a risk factor for the origin of diseases and production decreases in swine facilities--an epidemiologic study]. / Mykotoxine als Risikofaktor für das Entstehen von Krankheiten und Leistungsminderung in Schweinebeständen--eine epidemiologische Studie.

Feed samples checked for the mycotoxins zearalenone and ochratoxin A from the harvest 1987 were positive at a markedly higher percentage (37.5%) compared to previous years, which is explained by the especially unfavourable harvesting conditions of 1987. In certain herd problems affecting the digestive or respiratory tract, mycotoxins could be detected with a much higher frequency (64.7% and 50.0% respectively). The mean level detected in feed samples by thin layer chromatography ranged within 30.3 ppb for zearalenone and within 58.3 ppb for ochratoxin A. In most cases there was a history of infertility. Considering the clinical situation, which is presented comparatively in herds with positive mycotoxin results, the possible involvement of mycotoxins in the disease, even at very low concentrations, is pointed out. In this context, zearalenone is incriminated of being an indicator of a multitoxic process besides its own direct effects. According to own experiences low levels of zearalenone in the range of 20-50 ppb in the feed have to be considered hazardous. If changing of pig feed in cases of herd problems will be recommended, a level of less than 10 ppb of zearalenone, especially in sow and piglet rations, should not be exceeded. Same may be valid to ochratoxin A.

Comparison between a humanized cow's milk and a soy product for premature infants.

A soy-based infant feed was compared with a humanized cow's milk product in newborn preterm babies. Forty preterm infants appropriate for gestational age with birth weights of between 1,500 and 1,800 g were randomly allocated, as they were admitted, to either a soy feed or a humanized cow's milk formula--both commercial products. The trial lasted 35 days for each patient. With a formula intake of 180 ml/kg/day, the patients on the soy feed did not progress well, and most had to be withdrawn from the trial, whereas the group fed on cow's milk fared satisfactorily. With formula intakes of 200 ml/kg/d, progress in the group on the soy feed was improved. However, the body weights and serum albumin levels of the babies receiving the soy product were significantly lower than those of babies on the cow's milk formula at the end of the trial. Until more work has been done, we suggest that soy formulas should be employed with caution in the feeding of small preterm infants.