The Impact of Endourological Experience on Flexible Ureteroscopy Outcomes and Performance at Different Levels of Expertise: Retrospective Multifactorial Analysis.

INTRODUCTION: The aim of this study was to analyze the influence of residents' participation in flexible ureteroscopy (fURS) on intra- and postoperative outcomes. MATERIALS AND METHODS: Intra- and postoperative parameters were compared in a retrospective monocentric setting between 3 groups: "resident group" (47 cases) for surgeries performed by experienced residents alone, "consultant group" (245 cases) for surgeries performed by consultants alone, "resident plus consultant group" (124 cases) for training surgeries between September 2013 and June 2017. RESULTS: Patients operated by residents alone had a significantly smaller median kidney stone diameter (5.0 vs. 7.0 mm for "consultant group" and 6.0 mm for "resident plus consultant group," p = 0.011), shorter operating time (median 47.0 vs. 63.0 and 77.0 min, p < 0.001) and fluoroscopy time (median 39.0 vs. 69.5 and 89.0 s, p < 0.001), as well as shorter postoperative hospital stay (p = 0.013). The laser application rate was the smallest in the "resident group" (10.64 vs. 31.43 and 29.84%, p = 0.009). Univariate analysis revealed no relevant differences regarding flexible ureteroscope defect rate, postoperative stone-free rate, or ≥2 Clavien-Dindo classification complications between the groups (p > 0.05). CONCLUSION: A proper case selection of less complicated cases, especially without laser application, could balance the experience deficit of the residents. fURS can be incorporated as a part of residents' training without an impact on fURS device defect rate or clinical outcomes.

Exploiting the aiming beam to increase the safety of laser lithotripsy: Experimental evaluation of light reflection and fluorescence.

BACKGROUND AND OBJECTIVES: In Holmium laser lithotripsy, usually, the surgeon is guided by a visible beam superimposing the infrared (IR) treatment radiation. It has been shown that a green aiming beam excites stone autofluorescence. This fluorescence signal can be used for calculi detection to check the correct fiber position before triggering the IR laser, thus preventing damage to soft tissue and application devices. However, also the directly reflected green light from the fiber tip gives valuable information on fiber position and its surface condition. MATERIALS AND METHODS: An external fiber-fiber-coupling-box (fiber core diameter 365 µm) for pulsed holmium laser radiation (2.1 µm) was set up containing a green diode laser module (520 nm, average power on the sample <0.5 mW) and optics and detectors for measuring the reflected light of this aiming beam as well as the fluorescence excited with it. Measurements were done via a lock-in technique with more than 20 human calculi samples and porcine calix in vitro. After the implementation of automatic data storage signals during ongoing in vitro lithotripsy procedures were recorded with the fiber positioned on tissue, stone, or in/on medical equipment (working channel of an endoscope, stone retrieval basket). RESULTS: Stone fluorescence signals measured were a factor of 7 to >100 higher than those of tissue. Stone fluorescence was detectable in "non-contact mode" with a linear signal decrease over a distance up to ~1 mm in front of the fiber tip (core diameter 365 µm) and with severely damaged fibers (max. decrease: 75% with pinched off fiber). Reflection signals of the fiber tip surface in air and water surrounding decreased significantly when the fiber was damaged; measured ratios of intact to damaged fiber found in the air were (5-17):1 and in water (1.6-3.7):1. Surfaces in front of the fiber aggravated the evaluation of fiber condition due to reflections but enabled to detect, for example, the working channel of a flexible endoscope in combination with the (missing) fluorescence signal. CONCLUSIONS: Autofluorescence induced by a green aiming beam can be exploited for stone detection in laser lithotripsy. A reflection measurement can give further information on fiber condition and position. Implementing this kind of safety features for an automatic block of IR laser emission in case of weak or missing fluorescence and un-normal reflections can assist the surgeon by avoiding tissue perforation, and damage to medical devices such as endoscopes. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Laser fibre, rather than the stone, may harm the scope: retrospective monocentric analysis of 26 pre- and intraoperative factors of flexible ureteroscope (fURS) damage.

PURPOSE: The increasing number of flexible ureteroscopy procedures, the fragility of devices and their repair costs are a burden for urological departments worldwide. The objective was to investigate the impact of 26 pre- and intraoperative factors on reusable flexible ureteroscope (fURS) damage. METHODS: All procedures were conducted with reusable fURS: Karl Storz Flex-X2 or Olympus URF-V. Statistical analysis was performed in RStudio (1.0.136) with Chi-square test and Mann-Whitney U tests (MWU). RESULTS: In total, 416 flexible ureteroscopies, performed between September 2013 and June 2017, were analysed. 283 (68.03%) of these were for kidney stone surgery, and 133 (31.97%) for diagnostic purposes. In total, 39 (9.38%) devices were postoperatively deemed defective. The application of reusable laser fibre through fURS was more common in cases with documented defects [17/39 (43.59%) vs. 102/377 (27.06%), p = 0.047]. Other factors such as application of nitinol basket, biopsy via fURS, insertion of access sheath (UAS), as well as stone burden [median kidney stone maximal diameter: 6 mm (min 2.0; max 30.0) vs. 6 mm (min 1.0 vs. max 30.0)] showed no influence on fURS damage rate (p > 0.05). The infundibulopelvic angle (IPA) was steeper in cases with fURS damage as compared to cases without damage [median 44.0° (min 20.0; max 81.0) vs. 55.0 (min 7.0; max 122.0), p < 0.001]. CONCLUSIONS: Application of laser fibre via fURS can be considered as a risk factor of fURS damage. Stone burden, as well as the usage of not-sharp ended devices as nitinol baskets or forceps, is primarily not responsible for fURS damage.

Transient increased tumescence of the glans penis during penile erection after endovenous ablation of the great saphenous vein.

OBJECTIVE: The primary objective of our study was to investigate the impact of endovenous ablation of the great saphenous vein (GSV) on the degree of tumescence of the glans penis during penile erection as well as on global erectile function (EF). METHODS: We included patients scheduled for one of three different methods of endoluminal treatment. Our questionnaire was composed of the EF domain of the International Index of Erectile Function, an additional question that has been validated for assessment of swelling (tumescence) of the glans penis, and a question on the use of erectogenic medication. RESULTS: There were 62 patients enrolled in the study. Seven patients (11%) reported a postoperative enlargement of the glans penis on penile erection compared with the subjectively assessed glans tumescence before surgery. Three patients (5%) reported an increased tumescence of the glans 1 week after surgery, and four (7.4%) different patients reported the effect 3 months after surgery. Of these seven men, three had normal EF (score ≥26) at any time. One patient had mild erectile dysfunction before the operation, with an improvement to normal EF from week 1 throughout the observation in the study (3 months). CONCLUSIONS: This is the first prospective study that confirms an unexpected side effect of endoluminal treatment of the GSV occurring in approximately 10% of men. It might be of interest for insufficient responders to phosphodiesterase type 5 inhibitors with varicosis of the GSV in the future.

A New Automatically Fixating Stone Basket (2.5 F) Prototype with a Nitinol Spring for Accurate Ureteroscopic Stone Size Measurement.

INTRODUCTION: Intraoperative assessment of stone size is crucial for the successful and safe extraction of stones. The first automatically fixating measuring stone basket prototype showed a mismatch between the steel spring and the nitinol basket; therefore, to improve this prototype, the steel spring was replaced with a nitinol spring and a modified scale was implemented on the basket handle for accurate intraoperative stone size measurement. METHODS: The proposed tipped basket was composed of nitinol. A standard handle with a spring-supported self-closing mechanism (2.5 F, Urotech®) was used, and a modified nonlinear millimeter scale was established on the handle. The grasping force was provided by the new nitinol spring mechanism in the handgrip. Various colors associated with the stone size were applied on the scale. RESULTS: The material difference between the basket and the spring was eliminated. The measuring scale ranged from 2 mm (green) through 5 mm (yellow) to 8 mm (red), and the scale was nonlinear because of the nonlinear relationship between the diameter of the stone and the distance marked on the scale. CONCLUSION: The proposed automatically fixating stone basket with a nitinol spring has the potential to improve the safety and effectiveness of endourological stone retrieval. Further validation of this new scale and basket should follow.

Scents in the stack: olfactometric proficiency testing with an emission simulation apparatus.

Olfactometry is globally acknowledged as a technique to determine odor concentrations, which are used to characterize odors for regulatory purposes, e.g., to protect the general public against harmful effects of air pollution. Although the determination procedure for odor concentrations is standardized in some countries, continued research is required to understand uncertainties of odor monitoring and prediction. In this respect, the present paper strives to provide answers of paramount importance in olfactometry. To do so, a wealth of measurement data originating from six large-scale olfactometric stack emission proficiency tests conducted from 2015 to 2017 was retrospectively analyzed. The tests were hosted at a unique emission simulation apparatus-a replica of an industry chimney with 23 m in height-so that for the first time, conventional proficiency testing (no sampling) with real measurements (no reference concentrations) was combined. Surprisingly, highly variable recovery rates of the odorants were observed-no matter, which of the very different odorants was analyzed. Extended measurement uncertainties with roughly 30-300% up to 20-520% around a single olfactometric measurement value were calculated, which are way beyond the 95% confidence interval given by the widely used standard EN 13725 (45-220%) for assessment and control of odor emissions. Also, no evidence has been found that mixtures of odorants could be determined more precisely than single-component odorants. This is an important argument in the intensely discussed topic, whether n-butanol as current reference substance in olfactometry should be replaced by multi-component odorants. However, based on our data, resorting to an alternative reference substance will not solve the inherent problem of high uncertainty levels in dynamic olfactometry. Finally, robust statistics allowed to calculate reliable odor thresholds, which are an important prerequisite to convert mass concentrations to odor concentrations and vice versa.

Steep Infundibulopelvic Angle as a New Risk Factor for Flexible Ureteroscope Damage and Complicated Postoperative Course.

OBJECTIVE: The increasing number of flexible ureterorenoscopy (fURS) procedures, the fragility of devices, and their growing repair costs represent a substantial burden for urological departments worldwide. No risk factors of flexible ureteroscope damage have been identified so far. The objective of this study was to investigate the impact of infundibulopelvic angle (IPA) on device damage and on other intraoperative and postoperative factors such as length of hospital stay, surgical complications, stone-free rate (SFR), operation, and fluoroscopy time. MATERIALS AND METHODS: In a retrospective monocentric study, IPA was measured based on intraoperative retrograde pyelography images taken during fURS. All procedures were conducted with modern reusable flexible ureteroscopes: Karl Storz Flex-X2 or Olympus URF-V. Statistical analysis was performed in RStudio (version 1.0.136) with the unpaired t-test and Mann-Whitney U test. Pearson correlation coefficient (Pearson's r) was measured whenever applicable. RESULTS: In total, 381 fURS performed between September 2013 and March 2017 were analyzed: 260 (68.24%) for kidney stone operation and 121 (31.76%) for diagnostic purposes; of these, 38 (9.97%) devices were postoperatively deemed defective. IPA values were significantly steeper in cases with flexible ureteroscope damage compared to cases without damage (median 42.5 degrees vs 56.0, p < 0.001). Steeper IPA was significantly associated with the occurrence of Clavien-Dindo ≥2 complications (median 51.0 degrees vs 55.0, p = 0.005) as well as prolonged hospital stay (median 51.0 degrees vs 55.0, p = 0.014). No influence on SFR was observed (p > 0.05). IPA did not correlate with operation or fluoroscopy time. CONCLUSIONS: Steep IPA can be considered the first risk factor predicting both flexible ureteroscope damage and an unfavorable postoperative course. A better understanding of damage mechanisms is the key for the proper indications to use costly single-use devices.

Retrospective Cost Analysis of a Single-Center Reusable Flexible Ureterorenoscopy Program: A Comparative Cost Simulation of Disposable fURS as an Alternative.

OBJECTIVE: The increasing number of flexible ureterorenoscopy (fURS) procedures, the fragility of devices, and their growing maintenance and repair costs represent a substantial burden for urologic departments. Disposable single-use fURS devices offer many advantages over reusable fURS. Among them, the LithoVue™ model shows the best clinical utility. In our study, we assessed the economic aspects of reusable fURS application compared with the potential costs and benefits of single-use fURS (LithoVue™). Indications for single-use fURS were proposed based on potential risk factors of reusable fURS damage. MATERIALS AND METHODS: This single-center retrospective analysis compared the actual cost of reusable fURS procedures with the potential costs of LithoVue™ based on the price offered by the manufacturer. Consecutive case analysis of damaged fURS was performed to determine potential risk factors associated with fURS damage. RESULTS: The study group consisted of 423 reusable fURS procedures conducted between January 2013 and December 2016. During this period, 102 (24.11%) diagnostic fURS and 321 (75.89%) fURS for kidney stone therapy were performed. In 32 of 423 (7.57%) fURS cases, devices were postoperatively deemed defective, 9 of which were used for diagnostic procedures (9/102; 8.82%), 7 for stone removal (7/148; 4.73%), and 16 for stone removal and laser (Ho:YAG) application (16/173; 9.25%). The average cost per reusable fURS procedure was found to be €503.26. CONCLUSIONS: Disposable fURS is a more expensive option for high-volume centers. Based on our case analysis, laser disintegration treatment of multiple, large stones in the lower kidney pole of recurrent stone formers, as well as a steep infundibulopelvic angle (IPA ≤50°), seems to be the main risk factor for fURS damage. For these cases, disposable fURS may be a cost-effective alternative; however, a prospective comparison of economic outcomes between disposable and reusable fURS, together with confirmation of the proposed damage risk factors, is needed.

Stone/tissue differentiation for Holmium laser lithotripsy using autofluorescence: Clinical proof of concept study.

BACKGROUND AND OBJECTIVES: Holmium laser lithotripsy is the gold standard for intracorporeal fragmentation of urinary calculi. Usually, a visible beam is superimposed on the IR treatment laser as an aiming beam to guide the surgeon. In vitro tests showed that this aiming beam (532 nm, power <1 mW) excites strong fluorescence on human calculi. Tissue, in contrast, emitted much weaker fluorescence. If this is verified in vivo, the fluorescence signal induced by the aiming beam could be used to implement a feedback loop, preventing the Holmium laser being fired on tissue. MATERIALS AND METHODS: Fluorescence signals of 67 tissue and 68 stone spots were measured in a clinical proof of concept study with eight patients. For this, a modulated excitation/detection scheme (lock-in technique) was implemented. A frequency-doubled, diode-pumped solid-state laser module (532 nm, modulation frequency 66 Hz, average power 0.3 mW) was coupled via a dichroic mirror with the Holmium lithotripsy laser into the treatment fiber. The fluorescence signal entering the treatment fiber was detected via another dichroic mirror with a photodiode and a lock-in amplifier. RESULTS: In most instances (94%), the calculus of a patient gave a signal which was at least twice the maximum signal of ureteral tissue. CONCLUSION: The results of our proof of concept study indicate that measuring the fluorescence signal of a green aiming beam could be used to implement a feedback loop for Holmium laser lithotripsy. Preventing the laser being fired on tissue, this would increase the safety of the procedure. Lasers Surg. Med. 49:361-365, 2017. © 2016 Wiley Periodicals, Inc.

A comparison between an in vitro ureteroscopic stone size estimation and the stone size measurement with the help of a scale on stone baskets.

INTRODUCTION: Endoscopic treatment of ureter stones and renal calculi relies on the surgeon's estimation of the stone size for both lithotripsy and removal of stones or stone fragments. We therefore compared precision and reliability of the endoscopic estimation of stone size by the surgeon with measurements on a scale on a stone basket. MATERIALS AND METHODS: Two surgeons (one high experienced and one low experienced) first estimated, then measured the size of 12 stones differing in size and color using different stone baskets (2.5, 3.0, 4.0 Ch) each via a semirigid renoscope in an artificial ureter under water repeatedly on two different days. All together, we had 288 measurements and 288 estimations. RESULTS: On the whole, the accuracy of the estimation diminished with bigger stones. There is an increasing underestimation with increasing stone size. Factors, which significantly influence the estimation, are the operating surgeon, the color of the stone, the time sequence, and the size of the closed basket, which was held beside the stone. The accuracy of the measurement of the stone baskets is not as good as the estimation. The small 2.5-Ch basket is the most accurate in measuring big stones (>6 mm), the 3.5 Ch in intermediate stones (3-6 mm), the big basket (4.0 Ch) in small stones (<3 mm). CONCLUSION: This first attempt at validation of a scale on stone baskets shows different results for each basket which could be systematically improved. Until now, the estimation of the surgeons is better than the measurement, but it is also influenced by factors like the surgeon or the color of the stone.

Stone/tissue differentiation for holmium laser lithotripsy using autofluorescence.

BACKGROUND AND OBJECTIVES: Holmium laser lithotripsy is a safe and effective method to disintegrate urinary stones of all compositions in an endoscopic procedure. However, handling and safety could be improved by a real-time feedback system permanently monitoring the position of the treatment fiber. The laser is fired only when the fiber is identified as being placed in front of stone. This work evaluates the potential of fluorescence detection with an excitation wavelength of 532 nm for this purpose. MATERIALS AND METHODS: A fiber-based fluorescence measurement was set-up to acquire autofluorescence signals from several human renal calculi, artificial stones, and porcine tissue samples (renal calix and ureter). Three different approaches were investigated. First, experiments were performed with a pulsed laser source with a wavelength of 532 nm, pulse energy 36.5 ± 1 µJ, pulse duration 1.2 ± 0.5 nanoseconds, and a repetition rate of 1 kHz with 15 urinary concretions. In the second step, a series of measurements on 42 human urinary calculi samples was carried out using low power continuous wave excitation of 0.4 ± 0.1 mW. Fluorescence was also measured simultaneously to stone fragmentation by holmium laser pulses (pulse energy 240 ± 50 mJ, repetition rate 10 Hz). Finally, a modulated excitation/detection scheme (lock-in technique) was implemented to render fluorescence detection insensitive to white background light. RESULTS: Unlike porcine renal calix, ureter, and artificial stone human urinary calculi show a strong fluorescence signal when excited with 532 nm. With pulsed excitation on urinary stone (20,000 ± 11,000) counts were registered at 587 nm with the CCD-array of a grating spectrometer in an integration time of 50 milliseconds. Tissue gave lower count rates of ≤(5,500 ± 1,100) even with longer integration times (500 milliseconds/1 second). With a cw excitation power of 0.4 mW (13,000 ± 11,000) counts were registered in an integration time of 200 milliseconds at 587 nm (porcine renal calix: (770 ± 340)). Modulated excitation (66 Hz) with an average power of 0.3 mW and detection with a photodiode resulted in a lock-in amplifier signal of 1.5-4.3V on stone (background and skin: <0.5V). CONCLUSION: With the lock-in technique, autofluorescence from stones can be detected with only the average excitation power of a green aiming beam overlaid to the Ho:YAG-laser beam (power ≤ 1 mW). Since tissue shows very little autofluorescence when excited with 532 nm, this fluorescence signal enables monitoring of the correct position of the treatment fiber during ureteroscopic procedures.

Light-controlled macrocyclization of tetrathiafulvalene with azobenzene: designing an optoelectronic molecular switch.

Macrocyclization between tetrathiafulvalene (TTF) dithiolates and bis-bromomethylazobenzenes/bis-bromomethylstilbenes is investigated under high dilution conditions. We show that macrocycles of different size can be formed depending on whether the (Z)- or (E)-isomers of azobenzene (AB) or stilbene are used. This represents the first example of a light-controllable cyclization reaction. The oxidation potential of the small, structurally rigid TTF-AB macrocycle is found to depend on the conformation of the AB moiety, opening the way for the modulation of redox properties by an optical stimulus. DFT calculations show that the out-of-plane distortion of the TTF moiety in this macrocycle is responsible for the variation of its oxidation potential upon photoisomerization of the neighboring AB bridge.

Stone/tissue differentiation during intracorporeal lithotripsy using diffuse white light reflectance spectroscopy: In vitro and clinical measurements.

BACKGROUND AND OBJECTIVE: Holmium laser lithotripsy is the 'gold standard' for intracorporeal fragmentation of stones. However, there is a risk of damaging and perforating the ureter wall when the laser is accidentally fired while the fiber is in contact with tissue. The aim of this study was to evaluate if white illumination light, diffusely reflected back into the treatment fiber and spectrally analyzed, can be used for differentiating between stone and tissue. STUDY DESIGN/MATERIALS AND METHODS: Firstly, in vitro reflectance spectra (Xenon light source, wavelength range λ = 350-850 nm) of 38 human kidney stones, porcine renal calix and ureter tissue were collected. Secondly, in an in vivo study with 8 patients, 72 ureter and 49 stone reflectance signals were recorded during endourological interventions. The spectra were analyzed to discriminate between stone and tissue by the absence or presence of minima due to hemoglobin absorption at λ1 = 542nm and λ3 = 576nm. RESULTS: In vitro, all stone and tissue signals could correctly be identified by calculating the ratio R = I (λ1 = 542 nm)/I (λ2 = 475 nm): Because of the hemoglobin absorption at λ1 , R is smaller for tissue than for calculi. In vivo, only 75% tissue spots could correctly be identified utilizing this method. Using the more sophisticated evaluation of looking for minima in the diffuse reflectance spectra at λ1 = 542 nm and λ3 = 576 nm, 62 out of 64 tissue spots were correctly identified (sensitivity 96.9%). This was also the case for 39 out of 43 stone spots. Taking into account the number of measured spectra, a tissue detection probability of 91% and a stone detection probability of 77% was achieved (significance level 5%). CONCLUSION: White light diffusely reflected off the treatment zone into the fiber can be used to strongly improve the safety of Holmium laser lithotripsy by implementing an automatic feedback control algorithm that averts mispositioning the fiber.

Damage of stone baskets by endourologic lithotripters: a laboratory study of 5 lithotripters and 4 basket types.

Background. In some cases, the ureteral stone is simultaneously stabilized by a stone basket when endourologic lithotripsy is performed. This stabilization can be either on purpose or by accident. By accident means that an impaction in the ureter occurs by an extraction of a stone with a basket. A stabilization on purpose means to avoid a retropulsion of the stone into the kidney during lithotripsy. At this part of the operation, stone baskets have been frequently damaged. This severing of wires can lead to ureteral trauma because of hook formation. Material and Methods. In a laboratory setting, the time and the pulse numbers were measured until breaking the wires from four different nitinol stone baskets by using five different lithotripsy devices. The endpoint was gross visibledamage to the wire and loss of electric conduction. Results. The Ho:YAG laser and the ultrasonic device were able to destroy almost all the wires. The ballistic devices and the electrohydraulic device were able to destroy thin wires. Conclusion. The operating surgeon should know the risk of damagefor every lithotripter. The Ho:YAG-laser and the ultrasonic device should be classified as dangerous for the basket wire with all adverse effects to the patient.

1,7-diazaspiro[5.5]undecane--a neglected heterocycle.

A convenient and simple three step synthesis of 1,7-diazaspiro[5.5]undecane via Claisen condensation and acid catalyzed decarboxylation and spirocyclization of N-Boc-δ-valerolactam is described. Reactions of this spiroaminal with electrophiles including alkyl halides, alkane dihalides, acid chlorides, and sulfonyl chlorides gave either spirocyclic adducts or tetrahydropyridine derivatives. Additionally, the parent heterocycle is a novel bidentate ligand and formed complexes with ruthenium(II) and copper(II).

Could titanium oxide coating from a sol-gel process make stone baskets more resistant to laser radiation at 2.1 µm?

BACKGROUND: Stone baskets could be easily destroyed by Holmium:YAG-laser at an endourologic treatment, with respect to this, we try to improve the resistance by coating them with a titanium oxide layer. The layer was established by a sol-gel-process. MATERIALS AND METHODS: Six new baskets (Equadus, Opi Med, Ettlingen, Germany) were used: 1.8 Ch. with 4 wires (diameter 0.127 mm). Three baskets were coated with a layer of titanium oxide established by a sol-gel process at the BioCerEntwicklungs GmbH in Bayreuth (~100 nanometres thickness). The lithotripter was a Holmium:YAG laser (Auriga XL, Starmedtec, Starnberg, Germany). 10 uncoated and 10 coated wires were tested with 610 mJ (the minimal clinical setting) and 2 uncoated and 2 coated wires were tested with 110 mJ. The wires were locked in a special holding instrument under water and the laser incident angle was 90°. The endpoint was gross visible damage to the wire and loss of electric conduction. RESULTS: Only two coated wires resisted two pulses (one in the 610 mJ and one in the 110 mJ setting). All other wires were destroyed after one pulse. CONCLUSION: This was the first attempt at making stone baskets more resistant to a Holmium:YAG laser beam. Titanium oxide deposited by a sol-gel-process on a titanium-nickel alloy did not result in better resistance to laser injuries.

Palladium(0)-catalyzed allylic alkylation of diketoester-dioxinones with allyl acetates under neutral conditions: synthesis of hexasubstituted benzene derivatives.

Intermolecular palladium(0)-catalyzed allylic alkylation of diketoester-dioxinones was performed under neutral conditions with 2-alkenyl and 2-cycloalkenyl acetates. Subsequent aromatization using cesium carbonate gave rise to isopropylidene-protected hexasubstituted resorcylates.

Total syntheses of angelicoin A, hericenone J, and hericenol A via migratory prenyl- and geranylation-aromatization sequences.

A five-step synthesis of the natural product angelicoin A using a late stage highly regioselective palladium(0)-catalyzed decarboxylative prenyl migration and aromatization sequence as the key step is reported. The method was extended with geranyl migration in eight-step total syntheses of hericenone J and hericenol A from geraniol.

Destruction of stone extraction basket during an in vitro lithotripsy--a comparison of four lithotripters.

BACKGROUND: Various techniques are available for intracorporeal disintegration of renal and ureteral stones, among them ballistic lithotripsy, ultrasonic lithotripsy and laser lithotripsy. The therapeutic effectiveness of these devices has been sufficiently studied and compared. This does not apply, however, to the risk of destroying the stone basket. MATERIALS AND METHODS: The time until destruction of the wires of various baskets with use of four different lithotripsy devices (LithoClast, EMS; LithoRapid, Olympus; Calcuson 27610029, Storz; Vera Pulse, Coherent) was measured in a model closely aligned with the clinic. RESULTS: As expected, the direct application of laser pulses (wavelength 2.1 µm) irrespective of thickness and shape led to a melting of all wires of the stone extraction basket in less than 50 seconds (pulse energy: 800 mJ, pulse repetition rate: 8 hertz; fiber diameter: 365 µm). The purely kinetic functioning lithotripters (electrokinetic-ballistic and pneumatic-ballistic) were not able to destroy any wire within the set time limit of one minute. The sonotrode of the ultrasonic device, which is considered to be very tissue-conserving, separated all wires of baskets with a diameter of 1.8F (4 wires), 75% of baskets with a diameter of 2.5F (9 of 12), but only 8.3% of baskets with a diameter of 3.5F (1 of 12). Plaited wires demonstrated a good resistance (0 of 4) in comparison with the sonotrode. CONCLUSION: Our study consequently shows that in addition to the laser, the ultrasonic probe can also easily destroy nitinol (nickel titanium) baskets.

Synthesis of the isoquinocycline-pyrrolopyrrole substructure.

The synthesis of the pyrrolopyrrole substructure of the isoquinocyclines is reported. The pentacyclic (CDEFG) substructure of isoquinocycline A and B, which contains an unusual 2,4,5,6-tetrahydropyrrolo[2,3-b]pyrrole (FG) connected via an N,O-spiro acetal to the anthraquinoid core of the isoquinocycline aglycon has been synthesized. Key steps were a nickel(0)-mediated hydrocyanation of an alkynone, the conversion of an O,O-acetal into an N,O-acetal, and an intramolecular amidine alkylation.