Techniques and Outcomes of Salvage Robot-Assisted Radical Prostatectomy (sRARP)

BACKGROUND

Salvage Robot-Assisted Radical Prostatectomy (sRARP) has been described as feasible treatment for the management of localised prostate cancer (PCa) recurrence after primary treatment. However, no large reports have published cancer and quality outcomes.

OBJECTIVE

To report perioperative, functional and oncologic outcomes of sRARP in patients with localised PCa recurrence.

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively evaluated 106 patients with local recurrence eligible for sRARP.

SURGICAL PROCEDURE

Surgery was performed using the DaVinci Si system similar to the standard approach but with adaptation to the primary treatment.

MEASUREMENTS

Peri-operative outcomes included 90-day complication rate. Functional outcomes included rates of incontinence and erectile dysfunction. Oncological outcomes included tumour staging, margin rate and recurrence.

RESULTS AND LIMITATIONS

Primary treatment was High Intensity Focused Ultrasound (HIFU) in 59 (56%) patients, 27 (25%) radiotherapy, 10 (9%) seed brachytherapy, 8 (8%) solitary androgen deprivation therapy (ADT), one (1%) cryotherapy and one (1%) electroporation / Nanoknife. Median follow-up was 2.1 years. 90-day complication rate was 8%. At two years or more, 50% were fully continent and 33% were socially continent. Continence rates tended to be better after focal compared to whole-gland treatments. Erectile dysfunction was present in 95%. Positive surgical margin rate was 39%. Biochemical recurrence occurred in 13% and local or metastatic recurrence in 11%.

CONCLUSIONS

sRARP is technically more challenging but is a feasible option in high-volume centres for treatment of recurrent PCa. Patients should be counselled that functional outcomes are inferior to primary RARP. Adjustment of surgical technique according to the primary treatment is key for good surgical outcomes.

PATIENT SUMMARY

We report our experience with sRARP for the management of localised PCa recurrence after primary treatment. This represents a feasible approach with acceptable peri-operative complications and cancer outcomes. Functional outcomes are inferior to RARP in the primary setting.

Impedance-based sensor for potassium ions

A conductometric sensor for potassium ions in solution is presented. Interdigitated, planar gold electrodes were coated with a potassium-selective polymer membrane composed of a poly(vinyl chloride) matrix with about 65 wt% of plasticiser and 2-5 wt% of a potassium-selective ionophore. The impedance of the membrane was measured, using the electrodes as a transducer, and related to the concentration of potassium in a sample solution in contact with the membrane. Sensitivity was optimised by varying the sensor components, and selectivity for potassium over sodium was also shown. The resulting devices are compact, miniature, robust sensors which, by means of impedance measurements, eliminate the need for a reference electrode. The sensor was tested for potassium concentration changes of 2 mM across the clinically relevant range of 2.7-18.7 mM.

Combining mixed titania morphologies into a complex assembly thin film by iterative block-copolymer-based sol–gel templating

Sol–gel templating combined with iterative spin-coating steps are used to custom-tailor hierarchically structured titania thin films. Using poly(styrene-block-ethylene oxide) P(S-b-PEO) as the structure directing agent, a foam-like structure is combined with nanogranules. Both structural elements are merged into a complex assembly in thin film geometry. The resulting morphology is pictured by SEM and probed with GISAXS. The installed mesoporous titania sandwich structure exhibits holes with a size of 45 nm which makes it promising for applications in photovoltaics or photocatalysis. An optical characterization completes the structural investigation.

Mechanically strained a-Si:H AMOLED driver circuits

This paper examines the variations in performance of amorphous silicon (a-Si:H) thin-film transistor (TFT) pixel driver circuits for active-matrix organic light-emitting diode (AMOLED) displays, which are subject to compressive or tensile mechanical strain. The external strain is induced by bending of the TFT substrate, and is measured by the observed changes in resistance of in-situ strain gauges. Mechanical strain impacts the performance of the circuit in terms of its drive current, which may be attributed to mobility and Fermi energy shifts in the individual TFTs. The effect of strain-induced shifts in the TFTs as a function of strain orientation (longitudinal or transverse) with respect to direction of current flow is also examined. Our measurements show that the variation in the drain current of a longitudinally oriented TFT can be as much as ∼ 1.5% for strains as high as 10−3. Proper layout and circuit design can suppress the effect of strain-induced shifts, and should be taken into consideration when designing stable TFT driver circuits for mechanically flexible AMOLED displays.

Stability of Amorphous Silicon Thin Film Transistors for Analog Circuit Applications

Analog circuits using amorphous silicon thin film transistors offer significant advantages for in situ signal processing in large-area optical and x-ray imagers. However such circuits are susceptible to gate-bias-induced shifts in the threshold voltages of the constituent transistors. In this work, the change of threshold voltage for devices undergoing cycles of stress, relaxation and reverse bias is measured in order to determine the feasibility of resetting the threshold voltage electrically. It is concluded that, although the reverse bias does assist the recovery of the threshold voltage, the process is still not sufficiently rapid. An analog amplifier circuit is then described which uses negative feedback to achieve a gain that is stable to within 6% over a period of 8 hours.

A Novel Device Structure for High Voltage, High Performance Amorphous Silicon Thin-Film Transistors

Conventional high voltage thin-film transistors (HVTFTs) suffer from performance limitations such as low on-current, Vx. shift and large curvature in the linear region of the output characteristics. These limitations are associated with the highly resistive dead region in conventional HVTFT structures. In this paper, we present a novel TFT structure which has a high on-current, improved output characteristics in the linear region, and no Vx, shift. The higher on-current and significant improvement in output characteristics allows faster switching. Elimination of the Vx shift leads to more reliable circuit operation. The new structure is based on the conventional low voltage TFT (LVTFT) structure except that it does not suffer from low-voltage breakdown. The low-voltage breakdown of the gate nitride in conventional LVTFTs is perceived to be due to spiking of the drain metallization into the underlying layers which creates regions of very high electric field. In our novel structure, a higher breakdown is achieved by locating the metal contacts away from the gate edge while keeping the necessary drain to gate overlap through a heavily doped microcrystalline layer. Therefore, the new TFT extends the same performance as LVTFTs to high voltage operation. Furthermore, this structure also enhances the yield and reliability by minimizing the common faults in TFTs such as short circuits between gate, source and drain.

Parental perception of time and decision-making in neonatal research

OBJECTIVE

To assess the impact of time on parental decision-making for research participation for neonates with congenital heart disease.

STUDY DESIGN

Interviews were conducted with 37 parents of 19 neonates with congenital heart disease who were eligible for three different studies: genetic etiology of congenital heart disease, heart rate variability (HRV) and structural and functional cranial magnetic resonance imaging (MRI). All parents were asked the same questions: (1) 'Did you have adequate time to make a decision about research?' and (2) 'Why?' Differences between groups (reporting adequate and inadequate time) were evaluated using Fisher's exact tests; central themes were examined using qualitative analysis.

RESULT

Of those parents who reported having adequate time to make their decision (22 of 37), the majority chose to participate when compared to those who reported inadequate time (genetics study, P<0.01; HRV, P=0.05; MRI, P<0.01). For the parents reporting inadequate time, consistent themes emerged: insufficient time to make an educated choice (n=10), consideration of study logistics (n=8), spouse not present at the time of decision (n=7) and insufficient time to discuss the studies (n=4).

CONCLUSION

Parental perception of adequate time to decide about research participation was associated with parental willingness to enroll the child in research. Despite any time limitations, parents were satisfied with the decisions they made. Optimizing the time available for the parental permission process could enhance research participation in the neonatal period.

Perivascular graft heparin delivery using biodegradable polymer wraps

Heparin remains the gold-standard inhibitor of the processes involved in the vascular response to injury. Though this compound has profound and wide-reaching effects on vascular cells in culture and animal models, its clinical utility has been questionable at best. It is clear that the mode of heparin delivery is critical to its potential and it may well be that routine forms of administration are insufficient to observe benefit given the heparin's short half-life and complex pharmacokinetics. When ingested orally, heparin is degraded to inactive oligomer fragments while systemic administration is complicated by the need for continuous infusion and the potential for uncontrolled hemorrhage. Thus alternative heparin delivery systems have been proposed to maximize regional effects while limiting systemic toxicity. Yet, as heparin is such a potent antithrombotic compound and since existing local delivery systems lack the ability to precisely regulate release kinetics, even site-specific therapy is prone to bleeding. We now describe the design and development of a novel biodegradable system for the perivascular delivery of heparin to the blood vessel wall with well-defined release kinetics. This system consists of heparin-encapsulated poly(DL lactide-co-glycolide) (pLGA) microspheres sequestered in an alginate gel. Controlled release of heparin from this heterogeneous system could be obtained over a period of 25 days in vitro. The experimental variables affecting heparin release from these matrices were investigated. Gel permeation chromatography (GPC) and scanning electron microscopy (SEM) were used to monitor the degradation process and found to correlate well with the release kinetics. Heparin-releasing gels inhibited growth of bovine vascular smooth muscle cells in tissue culture in a dose-dependent manner. Moreover, gel release controlled vascular injury in denuding and interposition vascular graft animal models of disease even when uncontrolled bleeding was evident with standard matrix-type release. This system may therefore provide an effective means of examining the effects of various compounds in the control of smooth muscle cell proliferation in accelerated arteriopathies and also shed light on the biologic nature of these processes.

Intravenous crocetinate prolongs survival in a rat model of lethal hypoxemia

OBJECTIVE

To examine whether a carotenoid, trans-sodium crocetinate, has beneficial effects on hemodynamic status and short-term outcome in a rat model of lethal hypoxemia.

DESIGN

Randomized, placebo-controlled study.

SETTING

Medical school laboratory.

SUBJECTS

Eighteen spontaneously breathing, anesthetized Sprague-Dawley rats (six per group).

INTERVENTIONS

Rats underwent instrumentation to measure blood pressure, aortic and renal blood flow, arterial blood gases, bladder epithelial oxygen tension (by an intraluminal Clark electrode), and hepatic microvascular oxygen tension (measured by porphyrin phosphorescence). After stabilization, the rats were subjected to breathing 10% inspired oxygen concentration. After 10 mins, they were administered 1.25 mL/kg intravenous boluses of either isotonic saline (control), normal strength crocetinate (40 microg/mL), or a concentrated crocetinate solution (60 microg/mL). These boluses were repeated at 30-min intervals until either death or 3 hrs had elapsed.

MEASUREMENTS AND MAIN RESULTS

With the onset of hypoxemia, we observed a rapid reduction in blood pressure and renal blood flow, maintenance of aortic blood flow, an increase in arterial base deficit, and falls in oxygen tensions in arterial blood, bladder epithelium, and hepatic microvasculature. A progressive deterioration in the control rats was noted, with only two of the six animals surviving for 3 hrs. However, all 12 rats in the two crocetinate groups survived for 3 hrs, with hemodynamic stability until 150 mins and a slow decline thereafter.

CONCLUSIONS

Trans-sodium crocetinate improved hemodynamic status and prolonged survival in this model of severe acute hypoxic hypoxia. To our knowledge, this is the first demonstration of an intravenous agent having such an effect.

Drug resistance mutations can effect dimer stability of HIV-1 protease at neutral pH

The monomer-dimer equilibrium for the human immunodeficiency virus type 1 (HIV-1) protease has been investigated under physiological conditions. Dimer dissociation at pH 7.0 was correlated with a loss in beta-sheet structure and a lower degree of ANS binding. An autolysis-resistant mutant, Q7K/L33I/L63I, was used to facilitate sedimentation equilibrium studies at neutral pH where the wild-type enzyme is typically unstable in the absence of bound inhibitor. The dimer dissociation constant (KD) of the triple mutant was 5.8 microM at pH 7.0 and was below the limit of measurement (approximately 100 nM) at pH 4.5. Similar studies using the catalytically inactive D25N mutant yielded a KD value of 1.0 microM at pH 7.0. These values differ significantly from a previously reported value of 23 nM obtained indirectly from inhibitor binding measurements (Darke et al., 1994). We show that the discrepancy may result from the thermodynamic linkage between the monomer-dimer and inhibitor binding equilibria. Under conditions where a significant degree of monomer is present, both substrates and competitive inhibitors will shift the equilibrium toward the dimer, resulting in apparent increases in dimer stability and decreases in ligand binding affinity. Sedimentation equilibrium studies were also carried out on several drug-resistant HIV-1 protease mutants: V82F, V82F/I84V, V82T/I84V, and L90M. All four mutants exhibited reduced dimer stability relative to the autolysis-resistant mutant at pH 7.0. Our results indicate that reductions in drug affinity may be due to the combined effects of mutations on both dimer stability and inhibitor binding.