Mucoadhesive polymers: Design of S-protected thiolated cyclodextrin-based hydrogels

AIM

This study aims to design chemically crosslinked thiolated cyclodextrin-based hydrogels and to evaluate their mucoadhesive properties via mucosal residence time studies on porcine small intestinal mucosa and on porcine buccal mucosa.

METHODS

Free thiol groups of heptakis(6-deoxy-6-thio)-β-cyclodextrin (β-CD-SH) were S-protected with 2-mercaptoethanesulfonic acid (MESNA) followed by crosslinking with citric acid. Cytotoxicity was assessed by hemolysis as well as resazurin assay. Hydrogels were characterized by their rheological and mucoadhesive properties. Ritonavir was employed as model drug for in vitro release studies from these hydrogels.

RESULTS

The structure of S-protected β-CD-SH was confirmed by IR and 1H NMR spectroscopy. Degree of thiolation was 390 ± 7 µmol/g. Hydrogels based on native β-CD showed hemolysis of 12.5 ± 2.5 % and 13.6 ± 2.7 % within 1 and 3 h, whereas hemolysis of just 3.5 ± 2.8 % and 3.9 ± 3.0 % was observed for the S-protected thiolated CD hydrogels, respectively. Both native and S-protected thiolated hydrogels showed minor cytotoxicity on Caco-2 cells. Rheological investigations of S-protected thiolated β-CD-based hydrogel (16.2 % m/v) showed an up to 13-fold increase in viscosity in contrast to the corresponding native β-CD-based hydrogel. Mucosal residence time studies showed that thiolated β-CD-based hydrogel is removed to a 16.6- and 2.4-fold lower extent from porcine small intestinal mucosa and porcine buccal mucosa in comparision to the native β-CD-based hydrogel, respectively. Furthermore, a sustained release of ritonavir from S-protected thiolated β-CD-based hydrogels was observed.

CONCLUSION

Because of their comparatively high mucoadhesive and release-controlling properties, S-protected thiolated β-CD-based hydrogels might be promising systems for mucosal drug delivery.

Impact of laparoscopic versus open surgery on humoral immunity in patients with colorectal cancer: a systematic review and meta-analysis

BACKGROUND

Laparoscopic surgery (LS) is hypothesized to result in milder proinflammatory reactions due to less severe operative trauma, which may contribute to the observed clinical benefits after LS. However, previous systematic reviews and meta-analyses on the impact of LS on immunocompetence are outdated, limited and heterogeneous. Therefore, the humoral response after laparoscopic and open colorectal cancer (CRC) resections was evaluated in a comprehensive systematic review and meta-analysis.

METHODS

Included were randomized controlled trials (RCTs) measuring parameters of humoral immunity after LS compared to open surgery (OS) in adult patients with CRC of any stage. MEDLINE, Embase, Web of Science (SCI-EXPANDED), Cochrane Library, Google Scholar, ClinicalTrials.gov and ICTRP (World Health Organization) were systematically searched. Risk of bias (RoB) was assessed using the Cochrane RoB2 tool. Weighted inverse variance meta-analysis of mean differences was performed for C-reactive protein (CRP), interleukin (IL)-6, IL-8, tumour necrosis factor (TNF)α and vascular endothelial growth factor (VEGF) using the random-effects method. Methods were prospectively registered in PROSPERO (CRD42021264324).

RESULTS

Twenty RCTs with 1131 participants were included. Narrative synthesis and meta-analysis up to 8 days after surgery was performed. Quantitative synthesis found concentrations to be significantly lower after LS at 0-2 h after surgery (IL-8), at 3-9 h (CRP, IL-6, IL-8, TNFα) and at postoperative day 1 (CRP, IL-6, IL-8, VEGF). At 3-9 h, IL-6 was notably lower in the LS group by 86.71 pg/ml (mean difference [MD] - 86.71 pg/ml [- 125.05, - 48.37], p < 0.00001). Combined narratively, 13 studies reported significantly lower concentrations of considered parameters in LS patients, whereas only one study reported lower inflammatory markers (for CRP and IL-6) after OS.

CONCLUSION

The increase in postoperative concentrations of several proinflammatory parameters was significantly less pronounced after LS than after OS in this meta-analysis. Overall, the summarized evidence reinforces the view of a lower induction of inflammation due to LS.

Polyphosphate coated nanoparticles: Enzyme-activated charge-reversal gene delivery systems

AIM

The current study aimed to develop enzyme-activated charge-reversal lipid nanoparticles (LNPs) as novel gene delivery systems.

METHODS

Palmitic acid was covalently bound to protamine being utilised as transfection promoter to anchor it on the surfaces of LNPs. Green fluorescent protein (GFP) encoding plasmid DNA (pDNA) was ion paired with various cationic counter ions to achieve high encapsulation in LNPs. Protamine-decorated LNPs were prepared by solvent injection method followed by coating with sodium tripolyphosphate (TPP) to generate a bio-inert anionic outer surface. Resulting LNPs were characterised regarding size, polydispersity, zeta potential and encapsulation efficiency. Enzyme-triggered charge-reversal of LNPs was investigated using isolated alkaline phosphatase (ALP) monitoring changes in zeta potential as well as monophosphate release. Furthermore, monophosphate release, cell viability and transfection efficiency were evaluated on a human alveolar epithelial (A549) cell line.

RESULTS

Protamine-decorated and TPP-coated (Prot-pDNA/DcChol-TPP) LNPs displayed a mean size of 298.8 ± 17.4 nm and a zeta potential of -13.70 ± 0.61 mV. High pDNA encapsulation was achieved with hydrophobic ion pairs of pDNA with 3ß-[N-(N',N'-dimethylaminoethane)-carbamoyl]cholesterol hydrochloride (DcChol). Zeta potential of Prot-pDNA/DcChol-TPP LNPs reversed to positive values with a total Δ26.8 mV shift upon incubation with ALP. Conformably, a notable amount of monophosphate was released upon incubation of Prot-pDNA/DcChol-TPP LNPs with isolated as well as cell-associated ALP. A549 cells well tolerated LNPs displaying more than 95 % viability. Compared with naked pDNA, unmodified LNPs and control LNPs, Prot-pDNA/DcChol-TPP LNPs showed a significantly increased transfection efficiency.

CONCLUSION

Prot-pDNA/DcChol-TPP LNPs can be regarded as promising gene delivery systems.

Zeta potential shifting nanoemulsions comprising single and gemini tyrosine-based surfactants

AIM

This study aims to design and evaluate zeta potential shifting nanoemulsions comprising single and gemini type tyrosine-based surfactants for specific cleavage by tyrosine phosphatase.

METHODS

Tyrosine-based surfactants, either single 4-(2-amino-3-(dodecylamino)-3-oxopropyl)phenyl dihydrogen phosphate (AF1) or gemini 4-(2-amino-3-((1-(dodecylamino)-3-(4-hydroxyphenyl)-1-oxopropan-2-yl)amino)-3-oxopropyl)phenyl dihydrogen phosphate (AF2) type were synthesized via amide bond formation of tyrosine with dodecylamine followed by phosphorylation. These surfactants were incorporated into nanoemulsions. Nanoemulsions were monitored by incubation with isolated tyrosine phosphatase as well as secreted tyrosine phosphatase of Escherichia coli in terms of phosphate release and zeta potential change.

RESULTS

Via isolated tyrosine phosphatase, and mediated by E. coli, phosphate groups of either single or gemini tyrosine-based surfactants could be cleaved by secreted tyrosine phosphatase. Nanoemulsions comprising a single tyrosine-based surfactant resulted in a charge shift from - 13.46 mV to - 4.41 mV employing isolated tyrosine phosphatase whilst nanoemulsions consisting of a gemini tyrosine-based surfactant showed a shift in zeta potential from - 15.92 mV to - 5.86 mV, respectively.

CONCLUSION

Nanoemulsions containing tyrosine-based surfactants represent promising zeta potential shifting nanocarrier systems targeting tyrosine phosphatase secreting bacteria.

Intraoral Drug Delivery: Highly Thiolated κ-Carrageenan as Mucoadhesive Excipient

AIM

This study aims to design a novel thiolated κ-carrageenan (κ-CA-SH) and evaluate its potential as an excipient for the design of mucoadhesive drug delivery systems.

METHODS

Native κ-carrageenan (κ-CA) was thiolated with phosphorous pentasulfide in sulfolane and characterized via ¹H NMR, FTIR, as well as Ellman's test. Cytotoxicity was assessed via resazurin assay. In vitro release of the model drug, benzydamine hydrochloride, was determined. Tensile and mucosal residence time studies were performed on buccal and small intestinal mucosa. Mucoadhesive features were investigated via rheological studies with freshly isolated porcine mucus.

RESULTS

Thiolated κ-CA (κ-CA-SH) with 1213.88 ± 52 µmol/g thiol groups showed no cytotoxicity at a concentration of 1% (m/v) and low cytotoxicity up to 2% (m/v). Benzydamine hydrochloride showed slow release in solution for both polymers. Tensile studies on buccal and intestinal mucosa showed an up to 2.7-fold and 7.7-fold enhancement in the maximum detachment force (MDF) and total work of adhesion (TWA) of κ-CA-SH vs. κ-CA, respectively. The κ-CA-SH exhibited an up to 4.4-fold improved dynamic viscosity with mucus and significantly prolonged residence time on mucosa compared to native κ-CA.

CONCLUSION

Since highly thiolated κ-CA shows a slow release of positively charged active pharmaceutical ingredients and enhanced mucoadhesive properties, it might be a promising excipient for local drug delivery in the oral cavity.

Phosphatase-degradable nanoparticles: A game-changing approach for the delivery of antifungal proteins

HYPOTHESIS

Polyphosphate nanoparticles as phosphatase-degradable carriers for Penicillium chrysogenum antifungal protein (PAF) can enhance the antifungal activity of the protein against Candida albicans biofilm.

EXPERIMENTS

PAF-polyphosphate (PP) nanoparticles (PAF-PP NPs) were obtained through ionic gelation. The resulting NPs were characterized in terms of their particle size, size distribution and zeta potential. Cell viability and hemolysis studies were carried out in vitro on human foreskin fibroblasts (Hs 68 cells) and human erythrocytes, respectively. Enzymatic degradation of NPs was investigated by monitoring release of free monophosphates in the presence of isolated as well as C. albicans-derived phosphatases. In parallel, shift in zeta potential of PAF-PP NPs as a response to phosphatase stimuli was determined. Diffusion of PAF and PAF-PP NPs through C. albicans biofilm matrix was analysed by fluorescence correlation spectroscopy (FCS). Antifungal synergy was evaluated on C. albicans biofilm by determining the colony forming units (CFU).

FINDINGS

PAF-PP NPs were obtained with a mean size of 300.9 ± 4.6 nm and a zeta potential of -11.2 ± 2.8 mV. In vitro toxicity assessments revealed that PAF-PP NPs were highly tolerable by Hs 68 cells and human erythrocytes similar to PAF. Within 24 h, 21.9 ± 0.4 μM of monophosphate was released upon incubation of PAF-PP NPs having final PAF concentration of 156 μg/ml with isolated phosphatase (2 U/ml) leading to a shift in zeta potential up to -0.7 ± 0.3 mV. This monophosphate release from PAF-PP NPs was also observed in the presence of C. albicans-derived extracellular phosphatases. The diffusivity of PAF-PP NPs within 48 h old C. albicans biofilm matrix was similar to that of PAF. PAF-PP NPs enhanced antifungal activity of PAF against C. albicans biofilm decreasing the survival of the pathogen up to 7-fold in comparison to naked PAF. In conclusion, phosphatase-degradable PAF-PP NPs hold promise as nanocarriers to augment the antifungal activity of PAF and enable its efficient delivery to C. albicans cells for the potential treatment of Candida infections.

Thiolated cyclodextrins: A comparative study of their mucoadhesive properties

AIM

The aim of this study was the comparison of the mucoadhesive properties of nonionic, negatively, and positively charged thiolated cyclodextrins (CDs), including α-, β-, and γ-CDs of low and high degree of thiolation.

METHODS

Native α-, β-, and γ-CDs were thiolated with phosphorous pentasulfide in sulfolane (CD-SH) (i), via reductive amination with cysteamine after oxidative ring opening (CD-Cya) (ii), and via esterification with mercaptosuccinic acid (CD-MSA) (iii). These thiolated CDs were characterized via ¹H NMR and Ellman's test. Cytotoxicity was determined via resazurin and hemolysis assay. Mucoadhesive properties were evaluated via rheological studies with freshly isolated porcine mucus, as well as residence time studies on porcine small intestinal mucosa.

RESULTS

The structure of thiolated CDs was confirmed via ¹H NMR. The degree of thiolation was in the range of 594-1034 µmol/g for low and 1360-3379 µmol/g for high CD-SH, whereas thiolated CD-Cya and thiolated CD-MSA exhibited a degree of thiolation of 1142-3242 µmol/g and 243-1227 µmol/g, respectively. Just cationic CDs showed cytotoxicity. Nonionic highly thiolated α-CD-SH, α-CD-Cya, and α-CD-MSA exhibited with mucus 5.6-, 15.7- and 2.8-fold improved dynamic viscosity, while improvement was 7.7-, 6.1-, and 5.4-fold for the corresponding thiolated β-CDs and 12.3-, 15.4- and 17.8-fold for the corresponding thiolated γ-CDs compared with native CDs, respectively. A prolonged mucosal residence time following the rank order γ > β > α was observed for all thiolated CDs, whereby γ-CD-Cya, nonionic highly thiolated β-CD-SH and α-CD-Cya showed the highest mucoadhesive properties.

CONCLUSION

A high degree of thiolation and the introduction of cationic charges are mainly responsible for high mucoadhesive properties of CDs.

Betaine-modified hydroxyethyl cellulose (HEC): A biodegradable mucoadhesive polysaccharide exhibiting quaternary ammonium substructures

The aim of this study was to improve the mucoadhesive properties of hydroxyethyl cellulose (HEC) via the covalent attachment of betaine. Synthesis was carried out through esterification of HEC utilizing N-chlorobetainyl chloride. Betaine-modified HEC was characterized via FTIR and NMR analyses, ester quantification and zeta potential measurements. Enzymatic degradation and cell viability were also investigated. Moreover, rheological and mucoadhesive properties were evaluated. FTIR and NMR analyses confirmed the covalent attachment of betaine to HEC. Betaine-modified HEC contained 228.45±11.63 µmol/g ester bonds and its zeta potential was 0.37±0.19 mV. Enzymatic degradation studies showed the ability of lipase to cleave off betaine from HEC. Cytotoxicity studies demonstrated that betaine-modified HEC is up to a concentration of 0.3% not toxic. In comparison to unmodified HEC, betaine-modified HEC showed with mucus a 2.3- and 4-fold higher viscosity within 3 h and 6 h, respectively. Furthermore, betaine-modified HEC exhibited 23.5-fold higher mucoadhesive properties on porcine intestinal mucosa compared to unmodified HEC. In conclusion, betaine-modified HEC might be a useful biodegradable mucoadhesive polymer.

Nanoarchitectonics of Layer-by-Layer (LbL) coated nanostructured lipid carriers (NLCs) for Enzyme-Triggered charge reversal

HYPOTHESIS

Combined usage of Layer-by-Layer (LbL) coating and alkaline phosphatase (ALP) - responsive charge reversal strategies can improve the cellular internalisation of the colloidal drug delivery systems by also decreasing their cytotoxic effects.

EXPERIMENTS

Anionic core NLCs were formed by combining the melt emulsification method and ultrasonication. The resulting core NLCs were coated sequentially first with protamine (Prot NLCs) and then with sodium tripolyphosphate (TPP) or sodium polyphosphate (Graham's salt, PP) generating TPP or PP NLCs, respectively. The developed NLCs were characterised regarding their size and zeta potential. Enzyme-induced charge reversal of the TPP and PP NLCs was evaluated by zeta potential measurements upon their incubation with alkaline phosphatase (ALP). In parallel, time-dependent phosphate release was monitored in the presence of isolated as well as cell-associated ALP. Morphological evaluations were performed by scanning electron microscopy (SEM) studies. Moreover, cell viability and cellular uptake studies were carried out in vitro on Caco-2 cells.

FINDINGS

The core NLCs were obtained with a mean size of 272.27 ± 5.23 nm and a zeta potential of -25.70 ± 0.26 mV. Upon coating with protamine, the zeta potential raised to positive values with a total change up to Δ29.3 mV also displaying an increase in particle size. The second layer coating with TPP and PP provided a negative surface charge. Subsequent to ALP treatment, the zeta potential of the TPP and PP NLCs reversed from negative to positive values with total changes of Δ8.56 and Δ7.47 mV, respectively. Conformably, significant amounts of phosphate were released from both formulations. Compared with core NLCs, improved cellular viability as well as increased cellular uptake were observed in case of Prot, TPP and PP NLCs.

Phosphate decorated lipid-based nanocarriers providing a prolonged mucosal residence time

The aim of this study was to develop phosphate decorated lipid-based nanocarriers including self-emulsifying drug delivery systems (SEDDS), solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) to extend their mucosal residence time. All nanocarriers contained tetradecyltrimethylammonium bromide (TTAB) and polyoxyethylene (9) nonylphenol monophosphate ester (PNPP) for surface decoration. Zeta potential, cytotoxicity, charge conversion and phosphate release studies using isolated intestinal alkaline phosphatase (IAP) and Caco-2 cells were performed. Moreover, the residence time of nanocarriers was determined on porcine intestinal mucosa. Results showed a shift from negative to positive zeta potential due to the addition of TTAB and charge conversion back to a negative zeta potential when also PNPP was added. Up to a concentration of 0.3 %, lipid-based nanocarriers were not toxic. Charge conversion studies with IAP revealed the highest zeta potential shift for NLC_TTAB-PNPP with almost Δ22 mV. Phosphate release studies using isolated IAP as well as Caco-2 cells showed a fast phosphate release for SEDDS_TTAB-PNPP, SLN_TTAB-PNPP and NLC_TTAB-PNPP. SLN _TTAB-PNPP and NLC _TTAB-PNPP provided the highest increase in mucosal residence time that was 4-fold more prolonged than that of blank formulations. In conclusion, phosphate modified lipid-based nanocarriers can essentially prolong the intestinal residence time of their payload.

Nanostructured Lipid Carriers (NLCs) for Oral Peptide Drug Delivery: About the Impact of Surface Decoration

This study was aimed to evaluate the impact of surfactants used for nanostructured lipid carriers (NLCs) to provide enzymatic protection for incorporated peptides. Insulin as a model peptide was ion paired with sodium dodecyl sulfate to improve its lipophilicity. Three NLC formulations containing polyethylene glycol ester (PEG-ester), polyethylene glycol ether (PEG-ether), and polyglycerol ester (PG-ester) surfactants were prepared by solvent diffusion method. NLCs were characterized regarding particle size, polydispersity index, and zeta potential. Biocompatibility of NLCs was assessed on Caco-2 cells via resazurin assay. In vitro lipolysis study was performed using a standard lipid digestion method. Proteolytic studies were performed in simulated gastric fluid containing pepsin and simulated intestinal fluid containing pancreatin. Lipophilicity of insulin in terms of log Poctanol/water was improved from -1.8 to 2.1. NLCs were in the size range of 64-217 nm with a polydispersity index of 0.2-0.5 and exhibited a negative surface charge. PG-ester NLCs were non-cytotoxic up to a concentration of 0.5%, PEG-ester NLCs up to a concentration of 0.25% and PEG-ether NLC up to a concentration of 0.125% (w/v). The lipolysis study showed the release of >90%, 70%, and 10% of free fatty acids from PEG-ester, PG-ester, and PEG-ether NLCs, respectively. Proteolysis results revealed the highest protective effect of PEG-ether NLCs followed by PG-ester and PEG-ester NLCs for incorporated insulin complex. Findings suggest that NLCs bearing substructures less susceptible to degrading enzymes on their surface can provide higher protection for incorporated peptides toward gastrointestinal proteases.

Prospective observational cohort study on epidemiology, treatment and outcome of patients with traumatic brain injury (TBI) in German BG hospitals

OBJECTIVES

Since 2000/2001, no large-scale prospective studies addressing traumatic brain injury (TBI) epidemiology in Germany have been published. Our aim was to look for a possible shift in TBI epidemiology described in other European countries, to look for possible changes in TBI management and to identify predictors of 1-year outcome especially in patients with mild TBI.

DESIGN

Observational cohort study.

SETTING

All patients suffering from a TBI of any degree between 1 October 2014 and 30 September 2015, and who arrived in one of the seven participating BG hospitals within 24 hours after trauma, were included.

PARTICIPANTS

In total, 3514 patients were included.

OUTCOME MEASURES

Initial care, acute hospital care and rehabilitation were documented using standardised documentation forms. A standardised telephone interview was conducted 3 and 12 months after TBI in order to obtain information on outcome.

RESULTS

Peaks were identified in males in the early 20s and mid-50s, and in both sexes in the late 70s, with 25% of all patients aged 75 or older. A fall was the most frequent cause of TBI, followed by traffic accidents (especially bicyclists). The number of head CT scans increased, and the number of conventional X-rays of the skull decreased compared with 2000/2001. Besides, more patients were offered rehabilitation than before. Though most TBI were classified as mild, one-third of the patients participating in the telephone interview after 12 months still reported troubles attributed to TBI. Negative predictors in mild TBI were female gender, intracranial bleeding and Glasgow Coma Scale (GCS) 13/14.

CONCLUSION

The observed epidemiologic shift in TBI (ie, elderly patients, more falls, more bicyclists) calls for targeted preventive measures. The heterogeneity behind the diagnosis 'mild TBI' emphasises the need for defining subgroups not only based on GCS.

Less Reactive Thiol Ligands: Key towards Highly Mucoadhesive Drug Delivery Systems

As less reactive s-protected thiomers can likely interpenetrate the mucus gel layer to a higher extent before getting immobilized via disulfide bond formation with mucins, it was the aim of this study to develop a novel type of s-protected thiomer based on the less reactive substructure cysteine-N-acetyl cysteine (Cys-NAC) in order to obtain improved mucoadhesive properties. For this purpose, two types of s-protected thiomers, polyacrylic acid-cysteine-mercaptonicotinic acid (PAA-Cys-MNA) and polyacrylic acid-cysteine-N-acetyl cysteine (PAA-Cys-NAC), were synthesized and characterized by Fourier-transform infrared spectroscopy (FT-IR) and the quantification of attached disulfide ligands. The viscosity of both products was measured in the presence of NAC and mucus. Both thiomers were also evaluated regarding swelling behavior, tensile studies and retention time on the porcine intestinal mucosa. The FT-IR spectra confirmed the successful attachment of Cys-MNA and Cys-NAC ligands to PAA. The number of attached sulfhydryl groups was in the range of 660–683 µmol/g. The viscosity of both s-protected thiomers increased due to the addition of increasing amounts of NAC. The viscosity of the mucus increased in the presence of 1% PAA-Cys-MNA and PAA-Cys-NAC 5.6- and 10.9-fold, respectively, in comparison to only 1% PAA. Both s-protected thiomers showed higher water uptake than unmodified PAA. The maximum detachment force (MDF) and the total work of adhesion (TWA) increased in the case of PAA-Cys-MNA up to 1.4- and 1.6-fold and up to 2.4- and 2.8-fold in the case of PAA-Cys-NAC. The retention of PAA, PAA-Cys-MNA, and PAA-Cys-NAC on porcine intestinal mucosa was 25%, 49%, and 76% within 3 h, respectively. The results of this study provide evidence that less reactive s-protected thiomers exhibit higher mucoadhesive properties than highly reactive s-protected thiomers.

Zeta potential changing self-emulsifying drug delivery systems: A promising strategy to sequentially overcome mucus and epithelial barrier

AIM

The aim of the present study was to develop zeta potential changing self-emulsifying drug delivery systems (SEDDS) via a flip-flop mechanism in order to improve their mucus permeating and cellular uptake properties.

METHODS

Phosphorylated serine-oleylamine (p-Ser-OA) conjugates were synthesized and incorporated into SEDDS at a concentration of 1% (v/v). Cytotoxic potential of p-Ser-OA and p-Ser-OA loaded SEDDS was investigated on Caco-2 cells. Phosphate release was evaluated using isolated as well as cell-associated intestinal alkaline phosphatase (AP). In parallel, change in zeta potential and amino group concentration on the surface of SEDDS was determined. Furthermore, mucus permeation and cellular uptake studies were performed.

RESULTS

p-Ser-OA was synthesized by covalent attachment of serine (Ser) to oleylamine (OA) via a carbodiimide-mediated reaction followed by phosphorylation using phosphorous pentoxide (P₂O₅) and phosphoric acid (H₃PO₄). The chemical structure of p-Ser-OA was confirmed via FT-IR, ¹H NMR, ¹³C NMR, ³¹P NMR and mass spectroscopic analysis. p-Ser-OA loaded SEDDS exhibited a droplet size and zeta potential of 46.42 ± 0.35 nm and -11.53 mV, respectively. A significant amount of phosphate was released after incubation with isolated as well as cell-associated AP within 6 h and zeta potential raised up to -2.04 mV. p-Ser-OA loaded SEDDS showed improved mucus permeation in comparison to p-Ser-OA loaded SEDDS treated with AP. Moreover, cellular uptake increased almost 2-fold after phosphate cleavage using AP.

CONCLUSION

Findings of this study show that SEDDS changing their zeta potential via a flip-flop mechanism exhibit both high mucus permeating and high cellular uptake properties.

Entirely S-Protected Thiolated Silicone: A Novel Hydrophobic Mucoadhesive and Skin Adhesive

The aim of this study was the synthesis and evaluation of an entirely S-protected thiolated silicone as novel hydrophobic mucoadhesive and skin adhesive. 2-[(2-Amino-2-carboxyethyl)disulfanyl]nicotinic acid was covalently attached to a poly(dimethylsiloxane)-graft-polyacrylate via amide bond formation. Adhesive properties were determined via the rotating cylinder method and tensile studies on porcine small intestinal mucosa besides on porcine abdominal skin. Rheological characteristics were evaluated on a cone-plate rheometer. The S-protected thiolated silicone exhibited 128 ± 18 μmol immobilized 2-mercaptonicotinic acid per gram of polymer and showed a 5.9-fold extended time of mucosal adhesion compared with the unmodified silicone on the rotating cylinder. With a 2.3-fold higher maximum detachment force and a 1.7-fold higher total work of adhesion tested on porcine small intestinal mucosa, the S-protected thiolated silicone is superior to the unmodified silicone. Furthermore, using porcine abdominal skin, a 2.4-fold higher maximum detachment force and a 4.4-fold higher total work of adhesion obtained for the S-protected thiolated silicone outlines the preferentially adhesion to skin. Triggered by N-acetyl-L-cysteine liberated thiol groups form interchain and intrachain disulfide bonds within the polymer (6.7% m/v) causing a 23.0-fold increase in dynamic viscosity (ƞ). In parallel, the elastic modulus (G') and the viscous modulus (G") increased 39.2-fold and 8.1-fold, respectively.

Randomized clinical trial of prophylactic transanal irrigation versus supportive therapy to prevent symptoms of low anterior resection syndrome after rectal resection

Background

Low anterior resection syndrome (LARS) is a frequent problem after rectal resection. Transanal irrigation (TAI) has been suggested as an effective treatment in patients who have developed LARS. This prospective RCT was undertaken to evaluate the effect of TAI as a prophylactic treatment to prevent symptoms of LARS.

Methods

Patients who had undergone ultralow rectal resection were randomized to start TAI on a daily basis, or to serve as a control with supportive therapy only after ileostomy closure. All patients were seen after 1 week, 1 month and 3 months, and the maximum number of defaecation episodes per day and night documented during follow‐up. Wexner score, LARS score and Short Form 36 questionnaire responses were evaluated in both groups.

Results

Thirty‐seven patients could be evaluated according to protocol (TAI 18, control 19). The maximum number of stool episodes per day and per night was significantly lower among patients who underwent TAI at 1 month (median 3 versus 7 episodes/day in TAI versus control group, P = 0·003; 0 versus 3 episodes/night, P = 0·001) and 3 months (3 versus 5 episodes per day, P = 0·006; 0 versus 1 episodes/night, P = 0·002). LARS scores were significantly better in the TAI group after 1 month (median 16 versus 32 in control group; P = 0·044) and 3 months (9 versus 31; P = 0·001). A significantly better result in terms of Wexner score was seen in the TAI group after 3 months (median 2 versus 6 in controls; P = 0·046).

Conclusion

Prophylactic TAI led to a significantly better functional outcome compared with supportive therapy for up to 3 months. Registration number: DRKS00011752 ( http://apps.who.int/trialsearch/).

[Quality in coloproctology training : How is coloproctology training qualitatively integrated into the national training catalogue?]

The incorporation of coloproctology as a part of the surgical training and further education of assistant and specialist physicians shows great differences between Germany, Austria and Switzerland. In this article the international and national possibilities before and after specialist medical training are described in detail. In Austria, an optional coloproctology module can already be chosen in the third year of surgical training. Coloproctology is a compulsory component during the complete surgical training in Germany but a lower number of operations are required. In the basic module in Switzerland coloproctology is compulsory but contained in the operation catalogue to a lesser extent, although it has to be explicitly chosen in the further specialist training. The mandatory training in coloproctology in Germany enables all surgical assistants to undergo training, even if it is less intensive. As a result of partially compulsory and partially optional modules in Switzerland, a lower proportion of trainees receive specific training but it is more detailed. The number of trainees who are trained in coloproctology is even smaller in Austria due to the coloproctological training being optional. In the German-speaking regions a variety of specialized courses and further education are available for assistants and surgeons to further deepen their knowledge, no matter which form of training they had. At the international level the European Board of Surgical Qualification (EBSQ) for coloproctology has been available since 1998 and for many European specialists is the only possibility for formal specialization. The quality of a coloproctology training and further education curriculum may vary with national and international factors; however, it is a parameter for high standards in coloproctology in routine daily work, for the numbers of young coloproctology surgeons and is associated with a sufficient research performance in this discipline.

[Differential indications for ileoanal pouch anastomosis : Ulcerative colitis, familial adenomatous polyposis, synchronous colorectal cancer - Crohn's disease, constipation]

Ileoanal pouch anastomosis is the procedure of choice for patients with drug refractory ulcerative colitis, indeterminate colitis and familial adenomatous polyposis (FAP). In selected patient groups this procedure is a treatment option for patients with Crohn's disease, hereditary nonpolyposis colorectal cancer (HNPCC), synchronous colorectal cancer and for severe colorectal constipation refractory to conservative drug treatment. The pouch procedure provides the opportunity to avoid a permanent ileostomy. The majority of surgeons prefer the ileal J‑pouch as the construction is the easiest to perform and complications and dysfunction rates are low. Due to functional reasons most pouch surgeons favor a circular stapled ileoanal pouch anastomosis. The more radical proctocolectomy can produce sensory defects in the anal canal with subsequent soiling and incontinence. Studies have shown that even after proctocolectomy residual rectal mucosa was found in the anal canal. Therefore, the functionally important anorectal transitional zone should be preserved if possible. Ulcerative colitis can be "healed" with proctocolectomy; however, pouchitis can still occur in one third of the patients. Patients must be informed about the risk of pouchitis and a multidisciplinary monitoring and treatment strategy must be available. In Crohn's disease the ileoanal pouch survival rate of 80% in the long-term follow-up is surprisingly good despite an increased postoperative complication rate. The anal pouch anastomosis is the standard operation in patients with drug refractory ulcerative colitis, indeterminate colitis and FAP. Synchronous colorectal cancer, HNPCC and severe therapy refractive constipation represent rare indications for proctocolectomy where decisions must be made on an individual basis.

Evaluation of the Tekscan F-SCAN system for measurement of the kicking force in horses

INTRODUCTION

The incidence of fractures after a kick, coupled with marked soft tissue trauma at the site of injury, suggests that the force of a kick from the hind limb of a horse is enormous. The goal of this study was to measure this force and to investigate whether the Tekscan F-SCAN in-shoe pressure measuring system is suitable for quantification of the impact strength of a kick from a horse. The system was tested in 6 horses that had undergone clinical examination and gait analysis. The sensor-shoe combination was attached to each hind foot and the horse was stimulated to kick against a wall. The F-SCAN system measured the maximum vertical and horizontal force (N), the main contact area (cm2) of the sole with the floor (stance phase limb) or wall (kicking limb) and the duration (sec) that the sole was in contact with the floor or wall. In addition, each kicking event was recorded with a video camera for subjective evaluation. The mean kicking force measured was lower than that recorded in horses trotting on a treadmill, where the forces exerted on one limb were similar to the horse's body weight. The results of this study indicate that the Tekscan F-SCAN system is not ideally suited to measure the force of a kick of a horse in vivo.

[Historical development of drug testing in Swiss equestrian sports]

INTRODUCTION

The goal of this study was to describe the development of equine drug testing in horses in Switzerland. This was achieved through evaluation of a film made by the Institute of Forensic Medicine at the University of Basel entitled 'Doping von Rennpferden' [Doping of Race Horses], toxicological detection, 1962', the analysis of doping test results of the Swiss Equestrian Federation and by interviewing individuals of various professions who were involved in equine drug testing at the time. The study compares early and modern methods of drug testing and highlights the changes in the attitude of equestrian athletes, horse owners and the general public toward doping in equestrian sports. The high sensitivity of modern analytical methods allows the detection of drugs at levels considerably below therapeutic concentrations. This has resulted in a shift from zero tolerance for Controlled Medication Substances to the establishment of sub-therapeutic threshold concentrations. The lists of performance-enhancing drugs used in doping are updated continually. It became clear from this work that in the early 1960s, Switzerland played a leadership role in anti-doping in equestrian sports, and that the efforts to keep the sport free of performance-enhancing drugs remain exemplary.

[Gender-specific aspects of Lynch syndrome--an update]

Approximately 3-5% of all colorectal cancers are based on a hereditary predisposition, of which Lynch syndrome is by far the most frequent hereditary cancer syndrome. Beside colorectal cancer Lynch-Syndrome is the most frequent predisposing hereditary cause of endometrial cancer and is also associated with gastric cancer, ovarian cancer, cancer of the urinary tract as well as several other cancers. Genetically Lynch syndrome is caused by a germline mutation in one of the so-called mismatch-repair-genes. Based on several epidemiological studies, increasingly differences in the penetrance of the different cancers occurring are associated with the affected gene and also gender of the patient have been reported. The lifetime risk of colorectal cancer for males with Lynch syndrome generally is significantly higher and the age of first manifestation significantly earlier compared to females. The difference is especially notable in men with a MSH6-mutation. Moreover, the lifetime risk for gastric, bladder, and urothelial cancer is much higher in males. Women with an MSH6 mutation have a much higher risk for endometrial (and ovarian) cancer than for colorectal cancer. In patients with Muir Torre syndrome again males are predominantly affected and almost all affected have a mutation in MSH2 rather than in any other MMR gene. This review is an update of the literature analyzing gen and gender specific aspects of Lynch syndrome. To date these associations are based on retrospective studies, that require confirmation in a prospective setting with large patient numbers in order to identify validated, individualized gene and gender screening recommendations in the future. Especially in a syndrome with multiple potential cancer targets, an intense yearly program comprising several invasive procedures has a negative effect on patient compliance.

[Colorectal Carcinoma with Suspected Lynch Syndrome: A Multidisciplinary Algorithm]

Lynch syndrome is the most frequent hereditary cancer syndrome, accounting for approximately 3-5 % of all colorectal cancers. In addition, it is the most frequent predisposing hereditary cause of endometrial cancer and is also associated with gastric cancer, ovarian cancer, cancer of the urinary tract as well as several other cancers. In clinical practise Lynch syndrome is frequently not detected and many clinicians admit uncertainties regarding diagnostic procedures. Also, counselling of patients is considered difficult regarding therapeutic - especially prophylactic surgical and chemopreventive options and recommendations. Based on a review of available literature we discuss optimized strategies for improved detection of suspected Lynch syndrome patients. The aim of this review is to establish a clinical algorithm of how to proceed on a diagnostic level and to discuss surgical options at the time of a colorectal cancer. In order to identify patients with Lynch syndrome, family history should be ascertained and evaluated in regards to fulfilment of the Amsterdam-II- and/or the revised Bethesda criteria. Subsequently immunohistochemical staining for the mismatch-repair-genes, BRAF testing for MLH1 loss of expression, as well as testing for microsatellite instability in some, followed by genetic counselling and mutation analysis when indicated, is recommended. Pathological identification of suspected Lynch syndrome is readily feasible and straightforward. However, the need of performing these analyses in the tumor biopsy at the time of (gastroenterological) diagnosis of CRC neoplasia is essential, in order to offer patients the option of a prophylactically extended surgery and - as recommended in the German S3 guidelines - to discuss the option of a merely prophylactical hysterectomy and oophorectomy (if postmenopausal) in women. Close cooperation between gastroenterologists, pathologists and surgeons is warranted, so that patients may benefit from options of extended or prophylactically extended surgery at the time of diagnosis of a colorectal primary. Patients nowadays must be involved in informed decision-making regarding prophylactic or extended prophylactic surgery at the time of a colorectal primary. To date, however, limitations in daily clinical practise, the failure to assess family history and the lack of awareness of this important hereditary syndrome is the major asset leading to severe underdiagnosis and putting to risk the indexpatients themselves and their families to (metachronous) CRC and the associated extracolonic cancers. If at all tumors of patients fulfilling Bethesda criteria will be analysed for MSI in the surgical specimen and therefore Lynch syndrome patients are not given the opportunity to opt for extended surgery. In clinical experience the postoperative MSI-analysis is inconsistently performed - even if the Bethesda criteria are fulfilled - and in case of suspected Lynch syndrome genetically counselling is not consistently recommended. Therefore affected cancer patients are left unaware of their increased genetic risk and in average 3 high-risk gene carriers per family miss the opportunity to actively engage in the recommended screening program.

Health-related quality of life after laparoscopic and open surgery for rectal cancer in a randomized trial

Background

Previous studies comparing laparoscopic and open surgical techniques have reported improved health-related quality of life (HRQL). This analysis compared HRQL 12 months after laparoscopic versus open surgery for rectal cancer in a subset of a randomized trial.

Methods

The setting was a multicentre randomized trial (COLOR II) comparing laparoscopic and open surgery for rectal cancer. Involvement in the HRQL study of COLOR II was optional. Patients completed the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 and QLQ-CR38, and EuroQol – 5D (EQ-5D™) before surgery, and 4 weeks, 6, 12 and 24 months after operation. Analysis was done according to the manual for each instrument.

Results

Of 617 patients in hospitals participating in the HRQL study of COLOR II, 385 were included. The HRQL deteriorated to moderate/severe degrees after surgery, gradually returning to preoperative values over time. Changes in EORTC QLQ-C30 and QLQ-CR38, and EQ-5D™ were not significantly different between the groups regarding global health score or any of the dimensions or symptoms at 4 weeks, 6 or 12 months after surgery.

Conclusion

In contrast to previous studies in patients with colonic cancer, HRQL after rectal cancer surgery was not affected by surgical approach. Registration number: NCT0029779 (http://www.clinicaltrials.gov).