Electric Dipole Coupling of a Bilayer Graphene Quantum Dot to a High-Impedance Microwave Resonator.

We implement circuit quantum electrodynamics (cQED) with quantum dots in bilayer graphene, a maturing material platform that can host long-lived spin and valley states. Our device combines a high-impedance (Zr ≈ 1 kΩ) superconducting microwave resonator with a double quantum dot electrostatically defined in a graphene-based van der Waals heterostructure. Electric dipole coupling between the subsystems allows the resonator to sense the electric susceptibility of the double quantum dot from which we reconstruct its charge stability diagram. We achieve sensitive and fast detection of the interdot transition with a signal-to-noise ratio of 3.5 within 1 µs integration time. The charge-photon interaction is quantified in the dispersive and resonant regimes by comparing the resonator response to input-output theory, yielding a coupling strength of g/2π = 49.7 MHz. Our results introduce cQED as a probe for quantum dots in van der Waals materials and indicate a path toward coherent charge-photon coupling with bilayer graphene quantum dots.

Spin-Selective Equilibration among Integer Quantum Hall Edge Channels.

The equilibration between quantum Hall edge modes is known to depend on the disorder potential and the steepness of the edge. Modern samples with higher mobilities and setups with lower electron temperatures call for a further exploration of the topic. We develop a framework to systematically measure and analyze the equilibration of many (up to 8) integer edge modes. Our results show that spin-selective coupling dominates even for non-neighboring channels with parallel spin. Changes in magnetic field and bulk density let us control the equilibration until it is almost completely suppressed and dominated only by individual microscopic scatterers. This method could serve as a guideline to investigate and design improved devices, and to study fractional and other exotic states.

Intraoperative photodynamic evaluation of surgical margins during endoscopic extraperitoneal radical prostatectomy with the use of 5-aminolevulinic acid.

PURPOSE: Today there are no established techniques to image positive surgical margins (PSM) intraoperatively in endoscopic extraperitoneal radical prostatectomy (EERPE). The intention of this study was to describe the specific technique of photodynamic diagnosis (PDD) in patients undergoing EERPE and report on the potential to detect PSM under PDD. MATERIALS AND METHODS: Twenty-four patients with clinically organ-confined prostate cancer received 5-aminolevulinic acid 20 mg/kg body weight orally 3 hours prior to nonnerve-sparing EERPE. An endoscopic PDD system (Karl Storz, Tuttlingen, Germany) including a Tricam PDD 3-chip camera head linked with a straight 10-mm telescope and a D-light C system was used. During EERPE, visualization of the surgical margins was performed by means of both white light and PDD at specific steps during standardized prostatectomy in all patients. Positive PDD areas on the prostate specimen were marked with white ink and consequently processed in pathology. RESULTS: In white light endoscopy, no suspicion of a PSM was raised. Six out of the eight PSM were detected by PDD. In two cases, areas of positive PDD findings were free of prostate cancer and two PSM were not detected by PDD ( one bladder neck, one lateral). The overall sensitivity and specificity were 75% and 88.2%, respectively. CONCLUSIONS: Laparoscopy offers an appropriate setting for the use of PDD in prostate cancer to visualize possible PSM. Although imaging of PSM by PDD is promising with the technique being feasible and safe, larger series are needed to prove the reproducibility of our results.

Photodynamic diagnosis using 5-aminolevulinic acid for the detection of positive surgical margins during radical prostatectomy in patients with carcinoma of the prostate: a multicentre, prospective, phase 2 trial of a diagnostic procedure.

BACKGROUND: Surgical margin status after radical prostatectomy (RP) is a significant risk factor for tumour recurrence. It is an intriguing concept to find a fluorescence marker for photodynamic diagnosis (PDD) to make tumour margins visible during surgery. OBJECTIVE: To investigate the feasibility of identification of positive surgical margins (PSM) during open retropubic or endoscopic extraperitoneal RP by 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) to enhance surgical radicality. DESIGN, SETTING, AND PARTICIPANTS: Thirty-nine patients (Gleason score 6-10, prostate-specific antigen [PSA] 2.3-120 ng/ml) received 20 mg/kg of body weight of 5-ALA orally and underwent RP (24 endoscopic extraperitoneal, 15 open retropubic). MEASUREMENTS: A PDD-suitable laparoscopy optic (Karl-Storz GmbH, Tuttlingen, Germany) with a yellow long-pass filter was coupled to a fibre-optic light cord with an excitation light source (380-420 nm, D-Light, Karl-Storz GmbH, Tuttlingen, Germany) for fluorescence excitation of PpIX and to a PDD-suitable camera for video and photo documentation by the AIDA DVD system (Karl-Storz GmbH, Tuttlingen, Germany). RESULTS AND LIMITATIONS: There were more false-negative cases in the open group (four vs two) than in the endoscopic group but more false-positive cases in the endoscopic group (two vs none) than in the open group. The overall sensitivity and specificity were 56% and 91.6%, respectively. The sensitivity of the endoscopic cases was much higher (75% vs 38%) than for the open cases, while the specificity was higher for the open group (88.2% vs 100%). CONCLUSIONS: PDD with 5-ALA-induced PpIX during RP might be a feasible and effective method for reducing the rate of PSM. The technique seems to be more practicable during endoscopic RP rather than open RP. Further clinical studies with higher patient volumes and further development of the technique seem justified. TRIAL REGISTRATION: EudraCT: 2005-004406-93.

Photodynamic diagnosis of prostate cancer using 5-aminolevulinic acid--first clinical experiences.

OBJECTIVES: To study the feasibility of 5-aminolevulinic-acid (5-ALA)-induced photodynamic diagnosis (PDD) for the evaluation of the surgical margins (SMs) during radical prostatectomy (RP) in patients with prostate cancer (PCa). METHODS: A total of 18 patients with histologically confirmed PCa (Gleason score 4 to 8, prostate-specific antigen 1 to 20 ng/mL) underwent RP. Of the 18 patients, 16 received 5-ALA (20 mg/kg) orally 2 hours before RP, and 2 served as controls without any application of 5-ALA. To study the protoporphyrin IX (PPIX) accumulation after application of 5-ALA, all harvested specimens were investigated by fluorescence microscopy and spectroscopy. In 10 of 16 patients, PDD of the SMs and the prostate was performed during RP using an incoherent light source filtered for efficient fluorescence excitation. RESULTS: In all 16 patients, who had received 5-ALA fluorescence microscopy showed a selective accumulation of PPIX in the PCa cells, and only weak PPIX fluorescence could be detected in benign epithelial cells and none in the adjacent stroma. The 2 patients, who had not received 5-ALA had no PPIX fluorescence in the prostate. Of 10 patients, 8 demonstrated fluorescence-negative and histologically confirmed negative margins during PDD, and 1 each demonstrated a fluorescence-positive SM that was also confirmed by histologic examination and a positive SM that was not confirmed by PPD. CONCLUSIONS: This is the first report of PDD for PCa using 5-ALA. These initial results have demonstrated that PPIX is selectively enhanced in malignant tissue, an essential prerequisite of PDD. Additional studies are warranted to validate these preliminary data and the efficacy of PDD for PCa during RP.

Symphysitis following transrectal biopsy of the prostate.

Transrectal ultrasound-guided needle biopsy of the prostate is a widely accepted technique to obtain prostatic tissue for histological examination. Severe complications are rarely seen. We report a case of symphysitis causing hospitalization and severe pain and discomfort of the patient. Possible etiologic factors are traumatic osseous lesions and transport of rectal bacteria to the periosseous region. Especially in small prostates, care should be taken to avoid this condition. Prolonged perioperative antibiotic prophylaxis is mandatory.

Chromosome 9 deletions are more frequent than FGFR3 mutations in flat urothelial hyperplasias of the bladder.

Flat urothelial hyperplasias (FUHs) in patients with papillary bladder tumours frequently show deletions of chromosome 9, suggesting that FUH could be the first neoplastic step in the development of papillary bladder cancer. FGFR3 mutations are frequent in non-invasive papillary tumours with low risk of progression. Our aim was to investigate the frequency of FGFR3 mutations and deletions of chromosomes 9p/q and 8p/q in FUH. Thirty FUH and 9 simultaneous or consecutive tumours were detected by 5-ALA-based photodynamic cystoscopy. DNA was isolated from frozen sections and whole genome amplification was done by I-PEP-PCR, followed by LOH analysis on chromosomes 8p/q and 9p/q. FGFR3 mutations were detected by SNaPshot analysis. LOH analysis on FUH revealed deletions at 9p/q (11/30, 37%) and 8p/q (3/30, 10%). FGFR3 mutations were found in 7/30 FUH (23%). Only 2 FUH showed an FGFR3 mutation without deletions of chromosome 9. In contrast, 6 FUH revealed chromosome 9 deletions but wild type FGFR3 (p = 0.03). These results suggest that chromosome 9 deletions are the earliest genetic alterations in bladder cancer. The detection of FGFR3 mutations in FUH further supports the role of this lesion as precursor of papillary bladder cancer.

Retropubic transvesical prostatectomy for significant prostatic enlargement must remain a standard part of urology training.

OBJECTIVE: In recent years, open prostatectomy for benign enlargement has again become an issue of interest. We evaluated our experience with this procedure. Special attention was paid to the effect of the experience of the surgeon on operative outcome. MATERIAL AND METHODS: The patient files of 201 patients were evaluated retrospectively for operation outcome parameters. Statistical analysis was performed where appropriate. The different parameters were also analyzed separately for patients operated on by the head of the department and those operated on by residents. RESULTS: We found significant differences in pre- and postoperative median residual urine volume (85 vs 0.0 ml; p < 0.001) and pre- and postoperative median urinary flow (6.0 vs 20.8 ml/s; p < 0.001). There was a moderate correlation between preoperative determination of the prostate volume by means of transrectal ultrasound and postoperative histological weight. Patients operated on by the head of the department had a significantly shorter operation time. Postoperative complications were rarely seen in either group. The rates of postoperative complications were as follows: permanent incontinence, 0.5%; endoscopic revision (bleeding), 3%; open revision, 1%; urinary tract infection, 13%; and secondary wound healing, 5.5%. CONCLUSIONS: We feel that open prostatectomy remains an excellent technique for large prostate adenomas and should always be offered in such cases as a true alternative to endoscopic techniques. Having a well-trained urologist perform the procedure is the best guarantee of minimal blood loss and minimal complication rates. Therefore, open prostatectomy should be part of the education program of all prostate centers and urological departments.