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Herein, we report the first examples of the use of redox-active guanidines as catalysts in the green oxidation of organic molecules with dioxygen. In one half-reaction, the oxidized form of the redox-active guanidine is converted into the reduced, protonated state, thereby enabling dehydrogenative oxidation of the substrate (3,5-di-tert-butylcatechol→ortho-benzoquinone, benzoin→benzil, and 2,4-di-tert-butylphenol→biphenol). In the other half-reaction, efficient re-oxidation of the guanidine to the oxidized state is achieved with dioxygen in the presence of a copper catalyst. These results pave the way for the broader use of redox-active guanidines as oxidation catalysts., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Rationale Optimal secondary prevention of embolic stroke of undetermined source is not established. The current standard in these patients is acetylsalicylic acid, despite high prevalence of yet undetected paroxysmal atrial fibrillation. Aim The ATTICUS randomized trial is designed to determine whether the factor Xa inhibitor apixaban administered within 7 days after embolic stroke of undetermined source, is superior to acetylsalicylic acid for prevention of new ischemic lesions documented by brain magnetic resonance imaging within 12 months after index stroke. Design Prospective, randomized, blinded, parallel-group, open-label, German multicenter phase III trial in approximately 500 patients with embolic stroke of undetermined source. A key inclusion criterion is the presence or the planned implantation of an insertable cardiac monitor. Patients are 1:1 randomized to apixaban or acetylsalicylic acid and treated for a 12-month period. It is an event-driven trial aiming for core-lab adjudicated primary outcome events. Study outcomes The primary outcome is the occurrence of at least one new ischemic lesion identified by axial T2-weighted FLAIR magnetic resonance imaging and/or axial DWI magnetic resonance imaging at 12 months when compared with the baseline magnetic resonance imaging. Key secondary outcomes are the combination of recurrent ischemic strokes, hemorrhagic strokes, systemic embolism; combination of MACE including recurrent stroke, myocardial infarction, and cardiovascular death and combination of major and clinically relevant non-major bleeding defined according to ISTH, and change of cognitive function and quality of life (EQ-5D, Stroke Impact Scale). Discussion Embolic stroke of undetermined source is caused by embolic disease and associated with a high risk of recurrent ischemic strokes and clinically silent cerebral ischemic lesions. ATTICUS will investigate the impact of atrial fibrillation detected by insertable cardiac monitor and the effects of early anticoagulation with apixaban compared with antiplatelet therapy with acetylsalicylic acid on the incidence of new ischemic lesion after embolic stroke of undetermined source.

Ancient hydraulic lime mortar preserves chemical and isotopic signatures that provide important information about historical processing and its durability. The distribution and isotopic composition of calcite in a mortar of a well-preserved Punic-Roman cistern at Pantelleria Island (Italy) was used to trace the formation conditions, durability, and individual processing periods of the cistern mortar. The analyses of stable carbon and oxygen isotopes of calcite revealed four individual horizons, D, E, B-1 and B-2, of mortar from the top to the bottom of the cistern floor. Volcanic and ceramic aggregates were used for the production of the mortar of horizons E/D and B-1/B-2, respectively. All horizons comprise hydraulic lime mortar characterized by a mean cementation index of 1.5 ± 1, and a constant binder to aggregate ratio of 0.31 ± 0.01. This suggests standardized and highly effective processing of the cistern. The high durability of calcite formed during carbonation of slaked lime within the matrix of the ancient mortar, and thus the excellent resistance of the hydraulic lime mortar against water, was documented by (i) a distinct positive correlation of δ(18)Ocalcite and δ(13)Ccalcite; typical for carbonation through a mortar horizon, (ii) a characteristic evolution of δ(18)Ocalcite and δ(13)Ccalcite through each of the four mortar horizons; lighter follow heavier isotopic values from upper to lower part of the cistern floor, and (iii) δ(18)Ocalcite varying from -10 to -5 ‰ Vienna Pee Dee belemnite (VPDB). The range of δ(18)Ocalcite values rule out recrystallization and/or neoformation of calcite through chemical attack of water stored in cistern. The combined studies of the chemical composition of the binder and the isotopic composition of the calcite in an ancient mortar provide powerful tools for elucidating the ancient techniques and processing periods. This approach helps to evaluate the durability of primary calcite and demonstrates the importance of calcite as a proxy for chemical attack and quality of the ancient inorganic binder.

Objectives: The purpose of this study was to investigate the development of lateralization skills in children who received bilateral cochlear implants (CIs) in sequential operations., Methods: The lateralization skills of 9 children with a mean age of 4.1 years at the first surgery and 5.5 years at the second surgery were assessed at 3 time intervals. Children were assessed with a 3-loudspeaker setup (front, left and right) at 0.9 years (interval I) and 1.6 years (interval II) after the second implantation, and after 5.3 years of bilateral implant use (interval III) with a 9-loudspeaker setup in the frontal horizontal plane between -90° and 90° azimuth., Results: With bilateral implants, a significant decrease in lateralization error was noted between test interval I (45.0°) and II (23.3°), with a subsequent significant decrease at test interval III (4.7°). Unilateral performance with the CI did not improve significantly between the first 2 intervals; however, there was a bias of responses towards the unilateral side by test interval III., Conclusions: The lateralization abilities of children with bilateral CIs develop in a relatively short period of time (1-2 years) after the second implant. Children appear to be able to acquire binaural skills after bilateral cochlear implantation., (Copyright © 2013 S. Karger AG, Basel.)

The 715 patients who had crystalloid cardioplegia were compared with 5419 who had cold hyperkalemic blood cardioplegia for isolated coronary artery grafting from 1996 through 2001. Creatine kinase-MB was measured preoperatively, at 90 min, and 7 hours after the end of extracorporeal circulation. Correlation of post-bypass creatine kinase-MB release with aortic crossclamp time and other variables in the two cardioplegia groups was made using dichotomous encoding of cardioplegia in a multivariate linear regression model. Creatine kinase-MB levels 90 min after bypass were higher in patients who had crystalloid cardioplegia than in those who had blood cardioplegia. There was a linear relationship between aortic crossclamp time and post-bypass creatine kinase-MB release in both cardioplegia groups. Post-bypass creatine kinase-MB release increased with aortic crossclamp time independently of other factors and significantly more with crystalloid cardioplegia than with blood cardioplegia (the slope of the regression line was 0.230 versus 0.106). Intraaortic balloon pumping was used less frequently in the blood cardioplegia group. There was an advantage with blood cardioplegia for myocardial protection in longer aortic crossclamp times for isolated coronary bypass grafting.

The cochlear implantation, especially after bilateral operation provides a reliable and outstanding compensation in bilateral complete deafness or severe hearing impairment. Directional hearing can be restored with bilateral implantation so that warning signals are localized correctly and speech in noise is easier understood. Thus, rehabilitation is restored to a high degree. The involved expenses are severe, but are lower for the society when compared to the amount of money necessary to substitute a completely deaf patient lifelong.

Background: Cochlear implantation has become the method of choice for the treatment of deaf patients. A better technology of stimulation opened a wider field of patients suitable for cochlear implantation. Aim of the present study was to evaluate to which extent senior patients benefit by cochlear implantation., Patients and Methods: 36 patients between 65 and 85 years were tested by the Freiburger speech test for monosyllabic words and by the HSM sentence test with and without noise. The results were compared to those of younger implanted patients (16 - 64 years, n = 101)., Results: The speech perception for monosyllabic words did not differ significantly between both groups. A maximum plateau in speech perception for monosyllabic words was reached after 2 years at 55 %. The HSM sentence test revealed significant differences in the increase of speech perception between senior and younger patients in the first post surgical year. After one year elderly patients reached the same perception score as younger patients with a maximum of approximately 80 % after 3 years. At a signal to noise ratio of 15 % younger patients achieved a maximal perception of 55 % after 1 year whereas senior patients needed 4 years to reach this level., Conclusions: Senior patients benefited by cochlear implantation to the same extent as younger patients did. Senior patients gained a similar speech perception level as younger implanted patients although the elderly needed more time to reach the same scores. Nevertheless, cochlear implantation should not be denied due to age alone.

Objective: The purpose of the study was to investigate speech reception in noise in subjects who had undergone bilateral implantation with multichannel cochlear implants., Methods: Nine adults with bilateral MED-EL implants were included in the study. The subjects were tested using both implants and the better implant only. Tests were performed in a symmetrical setup, which ideally eliminates any head shadow effect. Speech tests included sentences in quiet and at various signal-to-noise ratios. From the results, the gain in signal-to-noise ratios at the speech reception threshold was determined., Results: All subjects showed a substantial gain in signal-to-noise ratios of approximately 4 dB on average. In addition, the gain in signal-to-noise ratios was essentially stable for as long as 4.4 years., Conclusions: The results indicate that bilateral cochlear implant users are able to binaurally process speech.

Background: About a decade ago a PC based system to document surgery and follow up evaluation was installed. At that time the wide spread DOS systems provided only inputs via the keyboard. However, we believed that to assure the system would be accepted by the user, a graphical user interface would be necessary. Such an interface provides greater user-comfort and ensures the validity of entered data., Methods: A simple graphical platform was installed, which provided all the necessary functions without being too complex. Several forms were designed for data collection. The first form implemented was designed for ear surgery. It comprises 356 items. The relevant data in the form are selected by a mouse click from possible alternatives. Although a large number of items are provided, it takes only one to two minutes to fill in the form., Results: At present, September 2001, the database contains 10 453 records related to ear operations, 9633 preoperative audiograms and the results from 16 140 follow up evaluations. A special language and an interpreter for analyzing the data were added to complete the system., Conclusions: The large number of cases stored in the database allows data analysis with a high level of statistical confidence for any conclusions based upon the data. It also allows investigations of the simultaneous influence of a large number of variables on the results.

Background: The goal of this study was to compare the auditory behaviour of bilaterally implanted children while using both CIs to their auditory behaviour during the time when they were using one CI., Methods: For this purpose a questionnaire looking at different aspects of hearing such as hearing in background noise, in complex listening situations and directional hearing was developed. The questionnaire was completed by the parents of 28 bilaterally implanted children. They were instructed to state their judgement on the behaviour of their children. The parents scaled their judgements using a method of extended category scaling similar to that applied in the loudness scaling with the Würzburg hearing field (WHF). Each of the five verbal categories was subdivided into 10 numerical subdivisions, so that the parents were able to express judgements lying between the different categories., Results: Eight out of eleven items showed that hearing with bilateral CIs was significantly better than with one CI (p < 0,003). The two items, which did not show a significant difference between the two conditions were those related to the interest in auditory rehabilitation and to aversion to noise., Conclusions: The questionnaire has proven to be a useful instrument to assess the quality of hearing in children. The possibility of bilateral implantation should be considered during the decision process prior to implantation.

One of the most consistently deleted chromosomal regions in solid tumours is 11q23-q25, which consequently has been postulated to harbour one or more tumour suppressor loci. Despite large efforts to identify the responsible genes, the goal remains elusive, but as knowledge accumulates new candidates are emerging. The present study was undertaken in an attempt to assess the possible implication of four genes residing at 11q23-q24, in a population of early onset breast cancer (n=41). The coding sequence of PIG8, CHK1, LOH11CR2A and PPP2R1B were screened for mutations using the protein truncation test or single-strand conformational polymorphism, in combination with direct DNA sequencing. Varying proportions of alterations were detected, ranging from 6% in PPP2R1B to 39% in PIG8. Many of these changes were deletions, in some cases corresponding to complete exons, thus likely to represent splice variants, while others were presumed to arise from aberrant splicing, since they occurred at sites with resemblance to exon/intron borders. Considering only bona fide mutations, the highest alteration frequency (17%) was again found in PIG8. Most of these alterations were likely to have an adverse impact on the translated protein as they either altered the reading frame or affected phylogenetically conserved residues. Our data represent the first evidence of alterations in the PIG8 gene in human malignancies, a finding that substantiates its role as a potential tumour suppressor gene as suggested by its involvement in p53-induced apoptosis.

Purpose: To evaluate in vitro the marginal quality of Class II composite restorations at the gingival enamel margins as affected by contamination of the cavities with gingival fluid (GF) during different steps of resin bonding procedures., Materials and Methods: 70 Class II cavities were prepared in extracted human molars and restored with composite using a multi-component bonding system (OptiBond FL/Herculite XRV; OPTI) or a single-bottle adhesive (Syntac Sprint/Tetric Ceram; SYN). The cavities were contaminated with human GF: C1 after acid etching, C2 after application of the primer (OPTI) or light-curing of the primer-adhesive (SYN), and C3 after light-curing of the resin adhesive (OPTI). Uncontaminated cavities were used as the control (C0). The restored teeth were subjected to thermocycling (TC) and replicated for SEM analysis of marginal gap formation. Microleakage at the gingival margins was determined by dye penetration with basic fuchsin., Statistics: non-parametric tests (Kruskal-Wallis test, Mann-Whitney test with Bonferroni correction)., Results: In both bonding systems, contamination with GF after acid etching (C1) did not impair the marginal quality; the mean percentages of continuous margin/mean depths of dye penetration were: OPTI: C0: 88.5%/0.10 mm, C1: 95.6%/0.04 mm; SYN: C0: 90.9%/0.08 mm, C1: 97.0%/0.05 mm. Marginal adaptation was adversely affected when GF contamination was performed after

Background: Any type of otosurgical procedure involves the risk of inner ear damage. As middle ear surgery is also performed for functional reasons this risk should be taken into consideration. The aim of this study was to analyse the frequency and the nature of sensorineural hearing loss following chronic ear surgery., Patients: A total of 3989 middle ear cases operated on between 1991 and February 1999 at the Department of Otorhinolaryngology, Head and Neck Surgery, University of Würzburg, Germany were studied retrospectively: 781 type I tympanoplasties, 2408 type III tympanoplasties and 800 cases of stapes surgery. The pre- and the postoperative audiograms in the frequency range between 500 and 8000 Hz were analysed and correlated to the different intraoperative findings., Results: Sensorineural hearing loss occurred in a total of 1.3% of 2224 patients with normal preoperative bone conduction thresholds: 0.2% became deaf, 0.8% acquired a high tone loss at 4 kHz and in 0.3% patients also 2 kHz was affected. None of the documented intraoperative complications such as bleeding, unexpected opening of a semicircular canal, extensive manipulation at the ossicular chain or a gusher phenoma showed a relevant effect on postoperative bone conduction thresholds. The incidence of high tone loss was not increased in cases of extensive drilling of the temporal bone. An unexpected opening of the vestibulum led to a small, but statistically significant change in postoperative bone conduction thresholds., Conclusions: Our results demonstrated that the risk for sensorineural hearing loss caused by middle ear surgery is low. None of the analysed factors seems to be a relevant prognostic risk factor for postoperative inner ear depression.

The vibrations of the ossicles were measured with a laser Doppler vibrometer in temporal bone specimens. The data contradicted the generally accepted view that the malleus and incus rotate about a fixed axis. The vibrations of the ossicles show a more complex pattern and, consequently, a more sophisticated model is needed to portray the behaviour of the middle ear in a satisfactory manner. But in turn models with many degrees of freedom make the identification process a very difficult task. This dilemma can be resolved if the system is divided into subsystems of less complexity where each subsystem can be studied in an appropriate manner. The excitation by electrostatic forces, as applied in this study, seems to be a powerful tool to make possible a study of parts of the ossicular chain.

Background: Following total laryngectomy the voice is produced by esophageal speech as well as with voice prostheses by vibrations of pharyngeal mucosal folds. This pharyngeal sound normally has a significantly lower fundamental frequency than the healthy voice (men about 120 Hz, women about 240 Hz, pharyngeal voice about 70 Hz), which is a handicap especially for female laryngectomy patients. In order to improve the postlaryngectomy voice, a new type of voice prostheses containing an integrated sound-producing metallic reed element was developed (ADEVA Company, Lübeck, Germany)., Methods/patients: Thirty-five of these new sound-producing voice prostheses were tested in vitro for different prosthesis-specific physical parameters (pressure, flow, sound pressure, flow resistance, frequency range). In 15 voice prosthesis speakers, a sound-producing prosthesis was introduced during a routine outpatient visit. Besides measurement of the above mentioned physical parameters in patients with conventional and sound-producing prostheses, the resulting voice as also evaluated by means of a video recording., Results: In vitro all prostheses with the metallic reed element produced a clear sound. Flow resistance of the prostheses was slightly elevated by the reed element. Insertion of the prostheses was hindered by the reed element. Period of uninterrupted sound production was prolonged after insertion of a sound-producing prosthesis and patients could speak on a lower pressure level, but the sound of the reed element was permanently distinguishable only in 6 of 15 patients., Conclusions: In principle a variation of the pharyngeal voice by means of a sound producing element, which is integrated into a voice prosthesis, is possible. The current design of the metallic reed element tested is not yet suitable for routine clinical use: 1. The reed element is too sensitive and is easily damaged during insertion, so the insertion device has to be improved. 2. The sound producing element is blocked by small amounts of tracheal secretions, so that this element should be replaceable separately without requiring removal of the silicone value (if possible by the patient himself). Prior to insertion of the sound producing voice prosthesis the maximum air flow through the shunt should be measured to determine if the patient can produce the necessary air flow for activation of the reed element. A further improvement for these special types of voice prostheses would be a sound producing element, which generates a variable frequency of sound. Limiting the patient to only one fundamental frequency creates a monotone, which does not sound naturally. Initial progress toward a sound-producing voice prostheses has been made. This should be followed by the necessary improvements in order to improve the feasibility of this design for routine clinical use.

Background: There is a reported 1% incidence of delayed migration of extrusions of the electrode arrays out of the cochlea., Methods: A titanium clip to fix the electrode array of the MED EL Combi 40 Cochlear Implant System is described. The clip is designed and shaped in a double U configuration. The clip material allows easy adaption to the individual anatomical situation. The clip is fixed to a bony bridge at the incus bar and fixes the electrode in a plane parallel to the chorda facial angle. It is closed around the electrode similarly to a stapes piston around the incus. Additional tests which examined the possible risk of damaging the electrode carrier and clinical findings are described., Results: The clip was used in 23 cases with a follow-up period up to 1 year. No signs for dislocation of the electrode were found. In one revision case the clip was covered with a thin mucosal layer. The electrode array showed no signs of damage. Intraoperative findings confirmed the experimental tests on the electrode fixation., Conclusion: The titanium clip facilitates safe and quick fixation of the electrode array and prevents dislocation. its flexibility and shape minimizes the risk of damage.

To improve the accuracy of measurements of left ventricular volume in the presence of an aneurysm, we used three-dimensional echocardiographic imaging to analyze the shape of left ventricles in 23 asymmetric model hearts with eccentric aneurysms of different sizes, shapes, and localizations. A standard 3.75 MHz ultrasound probe with a rotation motor device was used to obtain a three-dimensional data set. By rotating the probe stepwise 1 degree, 180 radial ultrasound pictures were digitized. On the basis of the three-dimensional data set, the following parameters were determined and compared with the dimensions of the model hearts obtained by direct measurement: total left ventricular volume (LVV), aneurysm volume, area of the aneurysm's base, the longest aneurysm long diameter, and the longest aneurysm cross diameter. In addition, quantification of LVV by three-dimensional echocardiography was compared with biplane two-dimensional echocardiographic measurement according to the disk method. Good agreements were found for LVV measured by both techniques, three-dimensional echocardiographic and direct measurement (mean of differences = 0.91 ml; SD of differences = +/- 6.23 ml; line of regression y = 1.07 x - 14.24 ml; r = 0.968; standard error of the estimate [SEE] = +/- 6.17 ml), aneurysm volume (mean of differences = 0.43 ml; SD of differences = +/- 2.14 ml; line of regression y = 1.05 x - 0.81 ml; r = 0.996; SEE = +/- 1.96 ml), area of the aneurysm's base (mean of differences = 0.24 cm2; SD of differences = +/- 1.72 cm2; line of regression y = 1.02 x - 0.02 cm2; r = 0.981; SEE = +/- 1.75 cm2), the longest aneurysm long diameter (mean of differences = -0.26 mm; SD of differences = +/- 1.60 mm; line of regression y = 0.97 x + 1.34 mm; r = 0.996; SEE = +/- 1.54 mm), and the longest aneurysm cross diameter (mean of differences = 1.35 mm; SD of differences = +/- 3.94 mm; line of regression y = 0.95 x + 3.17 mm; r = 0.941; SEE = +/- 3.99 mm). In contrast, in these extremely asymmetric-shaped model hearts, agreement between biplane two-dimensional echocardiographic and both direct LVV measurement (mean of differences = 7.8 ml; SD of differences = +/- 20.8 ml; line of regression y = 1.48 x - 92.45 ml; r = 0.874; SEE = +/- 18.36 ml) and three-dimensional echocardiographic measurements (mean of differences = -7.6 ml; SD of difference = +/- 18.1 ml; line of regression y = 0.59 x + 80.98 ml; r = 0.908; SEE = +/- 10.36 ml) was poor. Thus tomographic three-dimensional echocardiography allowed accurate volume determination of asymmetric model hearts in the shape of left ventricles with eccentric aneurysms.

Temporalis fascia remains the most widespread material for reconstructing the tympanic membrane in tympanomastoid surgery. If total or partial ossicular replacement prostheses are needed or pathology of the eustachian tube causes ventilation impairment, a more rigid transplant material is required. Between 1989 and 1994 perichondrium-cartilage composite grafts were used in a series of 597 cases of tympanomastoid surgery performed at the University ENT Clinic of Würzburg. The graft was taken from the tragus and prepared as a cartilage island with perichondrium attached to one side, the perichondrium-cartilage island transplant (PCI). If reconstruction of the ossicular chain was necessary, glass ionomer cement protheses (IONOS) were used. Closure of the tympanic membrane could be achieved in 90% of all cases. In those cases where ossicular chain reconstruction was postponed to a second procedure, closure of the drum was achieved in 96%. The audiological results of the different type III procedures were evaluated. By using the PCI technique a favorable closure of the air-bone gap to 10-25 dB was achieved, even in cases with advanced ear pathology technique and results are presented in detail.

In the past, the left atrial appendage has been considered a "useless" structure but associated to thromboembolic complications; its physiologic role is still undefined. Owing to its great distensibility, left atrial appendage positively influences atrial compliance and left ventricular performances. In addition this structure seems to play an important role in circulatory homeostasis by the release of atrial natriuretic factor in response to volume loading and atrial stretch. Transesophageal echocardiography provides a detailed anatomical characterization of this structure and, by means of Doppler flow velocities recordings, supplies relevant functional data. Despite their anatomical contiguity, the left atrium and atrial appendage result from a separate embryonic development; likewise, their function may differentiate. In the left atrial appendage a quadriphasic flow pattern has been described in subjects with sinus rhythm; however, as we reported, in some patients a more complex Doppler pattern can be observed, with an additional systolic forward flow wave which is presumably due to reflection phenomena. In patients with atrial fibrillation, an irregular flow pattern has been detected, which is mostly dependent on the duration of the arrhythmia, the underlying heart disease and the left atrial pressure. By transesophageal echocardiography a clear correlation has been established between the left atrial appendage slow flow and the occurrence of thromboembolic events; however, while waiting data from large studies, stratification of patients according to thromboembolic risk and decisions about anticoagulant prophylaxis should be performed by clinical information and transthoracic echocardiographic findings. No clinical or echocardiographic parameter has been found to be predictive of the thromboembolic events after cardioversion; in this setting the exclusion of atrial or atrial appendage thrombi by transesophageal echocardiography does not rule out the need for anticoagulation in patients with atrial fibrillation undergoing electrical or pharmacological cardioversion.

The electrical stimulation of the acoustic nerve is essential for evaluating patients for cochlear implants. Different tests are used to assess the performance of the cochlear nerve in a deaf ear. The use of category scaling of loudness leads to a more efficient test routine.

Transesophageal echocardiography is superior to transthoracic echocardiography in detection of superior to transthoracic echocardiography in detection of left atrial thrombi and spontaneous echocardiographic contrast, particularly in patients with atrial fibrillation and spontaneous echocardiographic contrast, thrombus formation is likely. In addition to the morphology, Doppler-echocardiography can be used to access left atrial appendage function. In patients with lone atrial fibrillation, reduced velocity was found in 60%, and no flow was detected in the left atrial appendage in 40%. These patients had a higher risk for spontaneous echocardiographic contrast and thrombus formation. As left atrial thrombi are found in 12% of patients, transesophageal echocardiography can be used to avoid cardioversion in these patients, which may lead to cerebral or peripheral emboli. Despite ruling out left atrial thrombi, embolism occurred after cardioversion when anticoagulation was insufficient or not performed. Current investigations are undertaken in order to demonstrate the clinical benefit of transesophageal echocardiography in patients with left atrial fibrillation.

Unlabelled: The present study focused on the accuracy and reproducability of measurements performed with a miniaturized pressure guidewire system (PGWS) under standardized in vitro conditions and in an isolated pig heart model. We used a pressure guide wire system provided by Pressure Guide, Radi Medical Systems, Uppsala, Sweden. Pressures were recorded by a fiber optic pressure sensor located laterally and 3 cm from the distal end. The basic principle is that the element modulates an optical reflection by pressure induced elastic movements. The light source is an emitting diode in the control unit. The PGWS replaces a standard 0.018 in. guidewire. The PGWS was introduced through a Y-adapter in a recirculating perfusion model, consisting of tubing with internal diameters from 1.00 to 4.00 mm. Different perfusion pressures (range 20-140 mm Hg) were generated by a pressure controlled roller pump., Results: Different lumen sizes from 1 to 4 mm had no influence on the measurements. a) In a range from 20 to 140 mm Hg no significant differences were found between the perfusion pressure and the pressures obtained by the PGWS, resulting in an r-value of 0.99 and an equation of y = 1.04x + 1.9. b) In pressure measurements proximal and distal of an artificial stenoses resulting in gradients from 0 to 100 mm Hg, the PGWS correctly identified the pressure difference with an equally high accuracy, 1, 2, and 3 cm behind the stenoses.(ABSTRACT TRUNCATED AT 250 WORDS)

In the total abdominal island skin flap of the rat based on both epigastric vessels in the groin, postoperative development after arterial or venous or complete division of the neurovascular bundle was documented. Photographic documentation, planimetry of the surviving skin area were used as methods together with evaluation of the blood supply of the flaps by Xe-133 clearance. The resulting new architecture of vessels was shown photomacroscopically by Indian ink injection. The function of arterial inflow and venous outflow was shown by microangiographical fluorescent methods. Hence, it was possible to combine special operation methods with definite new vessel structures, typical necrotic areas and postoperative mean value clearance results. Due to the difference of the xenon clearance results in individual cases, this method proved incapable of giving a safe prognosis on the survival of the special flap. Fluorescent microangiography pointed to the type of surgery which had been selected, and allowed functional evaluation of the blood supply of the flap.