Retrograde Versus Antegrade Nerve Sparing During Robot-assisted Radical Prostatectomy: Which Is Better for Achieving Early Functional Recovery?

Background

Although the retrograde approach to nerve sparing (NS) aimed at maximizing NS during robot-assisted radical prostatectomy (RARP) has been described, its significant benefits compared to the antegrade approach have not yet been investigated.

Objective

To evaluate the impact of NS approaches on perioperative, pathologic, and functional outcomes.

Design, setting, and participants

Five hundred one potent (Sexual Health Inventory for Men [SHIM] score >21) men underwent bilateral full NS and were followed up for a minimum of 1 yr. After propensity score matching, 344 patients were selected and were then categorized into two groups.

Surgical procedure

RARP with antegrade NS (n = 172) or RARP with retrograde NS (n = 172).

Outcome measurements and statistical analysis

Functional outcomes were assessed using validated questionnaires. Multivariable logistic regression models were applied.

Results and limitations

Positive margin rates were similar (11.1% vs 6.9%; p = 0.192), and no correlation with the NS approach was found on regression analysis. At 3, 6, and 9 mo, the potency rate was significantly higher in the retrograde approach (65% vs 80.8% and 72.1% vs 90.1% and 85.3% vs 92.9%, respectively). The multivariable model indicated that the NS approach was an independent predictor for potency recovery at 3, 6, and 9 mo, along with age, gland size, and hyperlipidemia. After adjusting for these predictors, the hazard ratio (HR) for the retrograde relative to the antegrade approach was 2.462 (95% confidence interval [CI], 1.482–4.089; p = 0.001) at 3, 4.024 (95% CI, 2.171–7.457; p < 0.001) at 6, and 2.145 (95% CI, 1.019–4.514; p = 0.044) at 9 mo. Regarding continence, the recovery rates at each time point and the mean time to regaining it were similar, and the method of NS had no effect on multivariable analysis. The absence of randomization is a major limitation of this study.

Conclusions

In patients with normal erectile function who underwent bilateral full NS, a retrograde NS approach facilitated early recovery of potency compared to that with an antegrade NS approach without compromising cancer control.     

Falcipain-1, a Plasmodium falciparum cysteine protease with vaccine potential

Cysteine proteases (falcipains) of Plasmodium falciparum are potential targets for antimalarial chemotherapy, since they have been shown to be involved in important cellular functions such as hemoglobin degradation and invasion/rupture of red blood cells during parasite life cycle. The role of falcipain-1 at the asexual blood stages of the parasite still remains uncertain. This is mainly due to a lack of methods to prepare this protein in an active form. In order to obtain biologically active falcipain-1, a number of falcipain-1 constructs were designed and a systematic assessment of the refolding conditions was done. We describe here the expression, purification, and characterization of a falcipain-1 construct encoding mature falcipain-1 and 35 amino acids from the C-terminal of the pro domain. Recombinant falcipain-1 was overexpressed in the form of inclusion bodies, solubilized, and purified by Ni²⁺-nitrilotriacetic acid affinity chromatography under denaturing conditions. A systemic approach was then followed to optimize refolding parameters. An optimum refolding condition was obtained, and the yield of the purified refolded falcipain-1 was ~1 mg/liter. Activity of the protein was analyzed by fluorometric and gelatin degradation assays. Immunolocalization studies using anti-falcipain-1 sera revealed a distinct staining at the apical end of the P. falciparum merozoites. Previous studies using falcipain-1-specific inhibitors have suggested a role of falcipain-1 in merozoite invasion. Based on its localization and its role in invasion, we analyzed the immunogenicity of falcipain-1 in mice, followed by heterologous challenge with Plasmodium yoelii sporozoites. Our results suggest a possible role of falcipain-1 in merozoite invasion.     

Interaction between cisplatin treated murine peritoneal macrophages and L929 cells: involvement of adhesion molecules, cytoskeletons, upregulation of Ca2+ and nitric oxide dependent cytotoxicity

Murine peritoneal macrophages on treatment with cisplatin (10 microg/ml) showed increased binding to L929 cells. Cisplatin treated macrophage on co-incubation with L929 cells form a distinct cytoplasmic contact between the two cells. The plasmalemmae of the two cells fuse over a large surface area. The formation of contact between the cisplatin treated macrophage and L929 cell results in the induction of apoptosis in L929 cell. Untreated macrophages did not form a contact with L929 cells and no apoptosis is observed in L929 cells. Immunofluorescence microscopical studies clearly show the participation of cytoskeleton and the adhesion molecules in the formation of contact between the two cells. Further, a significant enhancement of the expression of iNOS and cytosolic Ca2+ was observed in cisplatin treated macrophages co-incubated with L929 cells. Cisplatin treated macrophages produced significant amount of NO when co-incubated with L929 cells, while there was minimal production of NO by untreated macrophages co-incubated with L929 cells. Cisplatin treated macrophage-induced L929 cell death was NO dependent, since L-NMMA (500 microM) significantly inhibited the cytotoxicity of L929 cells. The addition of excess L-arginine (2mM) reversed the L-NMMA induced inhibition of NO production and L929 cell cytotoxicity.     

Arginine-α, β-dehydrophenylalanine Dipeptide Nanoparticles for pH-Responsive Drug Delivery

Purpose

Nanoparticles (NPs) exhibiting responsiveness towards pH variations in organs, tissue microenvironments and cellular compartments can significantly add on to the drug delivery potential. Here, we have developed NPs from an amphipathic dipeptide, Arginine-α, β-dehydrophenylalanine (RΔF), and tried to explore their pH responsive drug delivery potential in various cancer cells.

Methods

RΔF-NPs were architectured by harnessing the process of molecular self-assembly followed by the assessment of effect of pH on NPs morphology using zetasizer, SEM and CD. FTIR and PXRD analysis of the dipeptide and doxorubicin (Dox) were carried out for compatibility assessment followed by encapsulation of Dox in RΔF-NPs. RΔF-Dox-NPs were evaluated for pH dependent release as well as for in-vitro cellular internalization and efficacy in cancer cells.

Results

RΔF self-assembled to form monodispersed particles at pH 7. SEM analysis revealed a loss of overall particle morphology along with particle aggregation at highly acidic and basic pH respectively. The NPs demonstrated a slow and sustained release behaviour at pH 7 (97.64?±?4.71% after 36 h) in comparison to pH 2 (90.27?±?1.45% after 8 h) and pH 10 (96.39?±?3.87% after 12 h). In-vitro efficacy studies carried-out in various cancer cells revealed that RΔF-Dox-NPs exhibited higher efficacy with 1.65, 1.95 and 13.34 fold lower IC₅₀ values in comparison to Dox in C6, HCT-116 and AGS cell lines.

Conclusions

RΔF-Dox-NPs with higher drug release at acidic pH, enhanced internalization in cancer cells along with higher cytotoxic potential can act as effective pH responsive drug delivery systems.