Intravenous fate of poly(2-(dimethylamino)ethyl methacrylate)-based polyplexes

The objective of this study was to assess the in vivo fate of poly(2-(dimethylamino)ethyl methacrylate) (pDMAEMA)-based polyplexes after intravenous administration into mice. Circulation kinetics and tissue distribution in terms of plasmid localization and transfection efficiency were assessed. To gain more insight into the observed biodistribution and gene expression profile, the interaction of pDMAEMA-based polyplexes with blood components (erythrocytes and albumin) was investigated in vitro. In the case of i.v. injection of positively charged polyplexes at a dose of 30 microg DNA most of the radioactivity was found in the lungs and the liver 60 min after injection. In the case of pDMAEMA/DNA polyplexes with a negative charge, uptake occurred mainly by the liver. Administration of positively charged complexes at a 30 microg DNA dose resulted in reporter gene expression primarily in the lungs. Injection of negatively charged complexes and naked plasmid did not result in luciferase expression in any of the organs examined. In vitro turbidity experiments showed the induction of a charge dependent aggregation process upon addition of albumin to the polyplexes pointing out to the involvement of aggregate formation in the dominant lung uptake of the positively charged polyplexes. Also, incubations of polyplexes after pre-incubation with a physiological concentration of albumin with washed erythrocytes confirmed that polyplexes induce the formation of extremely large structures. This paper underlines the need for the design of systems with reduced interaction with blood components to promote the delivery of DNA to target tissues outside the lungs.     

Tissue reactions of in situ formed dextran hydrogels crosslinked by stereocomplex formation after subcutaneous implantation in rats

In this study, the in vivo biocompatibility of physically crosslinked dextran hydrogels was investigated. These hydrogels were obtained by mixing aqueous solutions of dextran grafted with L-lactic acid oligomers and dextran grafted with D-lactic acid oligomers. Gelation occurs due to stereocomplex formation of the lactic acid oligomers of opposite chirality. Since gelation takes some time, in situ gel formation is possible with this system. A number of sterilization methods was evaluated for their effect on the chemical and physical properties of the hydrogel. It was shown that of the investigated options (filtration, gamma irradiation, dry-heat and autoclaving) dry-heat sterilization was the preferred method to prepare sterile gels suitable for in vivo evaluations. Two types of stereocomplex gels were prepared and implanted subcutaneously in rats. The tissue reaction was evaluated over a period of 30 days. A mild ongoing foreign body reaction was observed characterized by infiltration of macrophages. Giant cells were only scarcely formed and the low numbers of lymphocytes showed that priming of the immune system is hardly involved. Importantly, the gels fully degraded in vivo within 15 days, which is in good agreement with the in vitro degradation behaviour of these gels. In conclusion, stereocomplexed dextran-oligolactic gels showed good biocompatibility which makes them suitable candidates for the design of controlled release devices for pharmaceutically active proteins.     

In vivo biocompatibility of dextran-based hydrogels

Dextran-based hydrogels were obtained by polymerization of aqueous solutions of methacrylated dextran (dex-MA) or lactate-hydroxyethyl methacrylate-derivatized dextran (dex-lactate-HEMA). Both nondegradable dex-MA and degradable dex-lactate-HEMA disk-shaped hydrogels, varying in initial water content and degree of substitution (DS, the number of methacrylate groups per 100 glucose units), were implanted subcutaneously in rats. The tissue reaction was evaluated over a period of 6 weeks. The initial foreign-body reaction to the dex-MA hydrogels was characterized by infiltration of granulocytes and macrophages and the formation of fibrin, and exudate, as well as new blood vessels. This reaction depended on the initial water content as well as on the DS of the hydrogel and decreased within 10 days. The mildest tissue response was observed for the gel with the highest water content and intermediate DS. At day 21 all dex-MA hydrogels were surrounded by a fibrous capsule and no toxic effects on the surrounding tissue were found. No signs of degradation were observed. The initial foreign-body reaction to the degradable dex-lactate-HEMA hydrogels was less severe compared with the dex-MA gels. In general, the size of the dex-lactate-HEMA hydrogels increased progressively with time and finally the gels completely dissolved. Degradation of the dex-lactate-HEMA hydrogels was associated with infiltration of macrophages and the formation of giant cells, both of which phagocytosed pieces of the hydrogel. A good correlation between the in vitro and the in vivo degradation time was found. This suggests that extra-cellular degradation is not caused by enzymes but depends only on hydrolysis of the ester and/or carbonate bonds present in the crosslinks of the hydrogels. After 21 days, the degradable hydrogels, as such, could not be retrieved, but accumulation of macrophages and giant cells was observed, both of which contained particles of the gels intracellularly. As for the dex-MA hydrogels, no toxic effects on the surrounding tissue were found. The results presented in this study demonstrate that dextran-based hydrogels can be considered as biocompatible materials, making these hydrogels attractive systems for drug delivery purposes.     

Immunogenicity of meningococcal PorA formulations encapsulated in biodegradable microspheres.

The purpose of our study was to investigate the possibility to microencapsulate liposomes and meningococcal outer membrane vesicles (OMV), both containing neisserial pore protein A (PorA), in biodegradable dextran- and mannan-based microspheres and to study the immunogenicity of the encapsulated PorA formulations. PorA-liposomes and OMV were encapsulated in dextran- or mannan-based microspheres by using an aqueous two-phase system consisting of a polyethylene glycol solution and a methacrylated dextran or mannan solution. The formulations were characterized for size distribution, PorA structure and antigen recovery after release. Calcein-containing model liposomes were used to establish the encapsulation efficiency and release profiles from both types of microspheres. The immunogenicity of the PorA-containing formulations was determined in mice after subcutaneous immunization. Liposomes were encapsulated in dextran and mannan microspheres with a high efficiency (70-90%). Calcein liposomes, after a 5-day lag period, exhibited apparent zero-order release kinetics from both types of microspheres between Days 5 and 10 of incubation in vitro. The total release was 80 and 100% from mannan and dextran microspheres, respectively. The trimeric PorA conformation was preserved in the released liposomes and OMV and the antigen was partly recovered. The immunogenicity of PorA-liposomes and OMV encapsulated in dextran or mannan microspheres was preserved. In conclusion, PorA-liposomes and OMV could be encapsulated in dextran- and mannan-based microspheres with high efficiency. The immunogenicity of encapsulated antigen was preserved.     

Interleukin-10 promoter polymorphisms in rheumatoid arthritis and Felty's syndrome

OBJECTIVE: To examine whether promoter polymorphisms associated with variation in interleukin-10 (IL-10) production are relevant to the development of rheumatoid arthritis (RA) or Felty's syndrome (FS). METHODS: DNA was obtained from 44 FS patients, 117 RA patients and 295 controls. The promoter region between -533 and - 1120 was amplified by polymerase chain reaction, and polymorphisms detected by restriction enzyme digest or sequence-specific oligonucleotide probing. RESULTS: We found no significant difference in allele or haplotype frequencies between the groups. CONCLUSION: There is no association between FS or RA and these recently identified IL-10 promoter polymorphisms. Other genetic or environmental factors could explain the alterations in IL-10 levels seen in these conditions.      

Purging of acute myeloid leukemic cells by ether lipids and hyperthermia

Ether lipids (EL) and hyperthermia have been shown to possess a relatively selective cytotoxicity to leukemic cells. In this study, the combined effects of EL (ET-18-OCH3, ET-16-NHCOCH3, or BM 41.440) and hyperthermia on the growth of hematopoietic progenitors, myeloid leukemic cell lines, and leukemic cells obtained from patients with acute myeloid leukemia (AML) were examined to determine if this combination resulted in a greater selective killing of leukemic cells than that achieved by either EL or heat alone. When the cells were treated simultaneously with EL (50 micrograms/mL) and hyperthermia (42 degrees C) for one hour, the killing of leukemic cell line cells was enhanced considerably. Among the three EL, however, the combination of ET-18-OCH3 and heat seemed to be the most cytotoxic to leukemic cell line cells with no effect on the growth of hematopoietic progenitors. An increase in the duration of treatment with ET-18-OCH3 to four hours with heat added during the last hour resulted in a further reduction of leukemic cell line cells while sparing 50% of hematopoietic progenitors after cryopreservation. The combined treatment with ET-18-OCH3 and heat also inhibited the growth of leukemic progenitors obtained from AML patients by 97% to 100%. These data indicate that the combined treatment with EL and hyperthermia might offer an efficient means to eliminate myeloid leukemic cells in vitro.     

Alginate–lanthanide microspheres for MRI-guided embolotherapy

In cancer therapy, a promising treatment option to accomplish a high tumor-to-normal-tissue ratio is endovascular intervention with microsized particles, such as embolotherapy. In this study, alginate microspheres (ams) were prepared with the JetCutter technique, which is based on cutting a sodium alginate solution jet stream into small droplets of uniform size which are then cross-linked with different lanthanides or iron-III, resulting in microspheres of a predefined size which can be visualized by magnetic resonance imaging (MRI). The microspheres were investigated for their size and morphology (light microscopy and scanning electron microscopy analysis), cation content and MRI properties. The lanthanide-ams formulations, with a uniform size of 250 μm and a cation content between 0.72–0.94%, showed promising results for MR imaging. This was further demonstrated for Ho³⁺-cross-linked alginate microspheres (Ho³⁺-ams), the most potent microsphere formulation with respect to MR visualization, allowing single sphere detection and detailed microsphere distribution examination. Intravascular infusion of Ho³⁺-ams by catherization of ex vivo rabbit and porcine liver tissue and assessment of the procedure with MRI clearly showed accumulation and subsequently embolization of the targeted vessels, allowing accurate monitoring of the microsphere biodistribution throughout the tissue. Therefore, the different alginate–lanthanide microsphere formulations developed in this study show great potential for utilization as image-guided embolotherapy agents.     

完全腹腔镜Roux—en—Y吻合术式应用于远端胃癌根治术20例

目的探讨完全腹腔镜Roux．en—Y吻合术式应用于远端胃癌根治术的安全性和可行性。方法回顾性分析福建省肿瘤医院腹部外科2012年8月至2013年3月对腹腔镜胃大部切除术后实施完全腹腔镜Roux．en—Y吻合术的20例胃癌患者的术中和术后临床资料。结果20例患者均成功实施完全腹腔镜远端胃癌根治术,无一例中转开腹或中转腹腔镜辅助手术。手术时间（190．8±53．6）min,术中出血量（122．4±57．7）ml,淋巴结清扫数（31．2±5．7）枚,术后病理切缘均为阴性。术后排气时间为（2．6±1．6）d,住院时间为（8．1±2．0）d。有1例术后出现肺部感染,但无吻合术相关并发症发生。结论完全腹腔镜Roux—en—Y吻合术式应用于远端胃癌根治术安全且可行。     

Identification of familial colorectal cancer and hereditary colorectal cancer syndromes through the Dutch population-screening program: results ofa pilot study

Objectives: In 2014, a population-screening program using immuno-faecal occult blood testing (I-FOBT) has started in the Netherlands. The aims of this study were to evaluate the proportion of individuals in the Dutch screening program with a positive I-FOBT that fulfill the criteria for familial colorectal cancer (FCC) and to evaluate the proportion of participants that needs genetic counseling or colonoscopic surveillance.

Material and methods: This retrospective observational study was performed in two large hospitals. Individuals aged between 55 and 75 years with a positive I-FOBT that underwent colonoscopy were included. A detailed family history was obtained in all individuals.

Results: A total of 657 individuals with a positive I-FOBT test underwent colonoscopy. A total of 120 (18.3%) participants were found to have a positive family history for CRC, 20 (3.0%) fulfilled the FCC criteria, 4 (0.6%) the Bethesda guidelines and 1 (0.2%) participant the Amsterdam criteria. Multiple adenomas (>10) were found in 21 (3.2%) participants. No cases of serrated polyposis were identified. Based on these criteria and guidelines, a total of 35 (5.3%) required referral to the clinical geneticist and the relatives of 20 (3.0%) participants should be referred for surveillance colonoscopy.

Conclusion: Obtaining a detailed family history at the time of intake of participants with a positive I-FOBT in the Dutch surveillance program increased the identification of participants with familial CRC.     

The Use of Magnetic Resonance Imaging for Non-Invasive Assessment of Venofer® Biodistribution in Rats

Purpose

The aim of this study was to determine the potential of magnetic resonance imaging to evaluate the biodistribution of exogenous iron within 24 h after one single injection of Venofer® (iron sucrose).

Methods

Venofer® was evaluated in vitro for its ability to generate contrast in MR images. Subsequently, iron disposition was assessed in rats with MRI, in vivo up to 3 h and post mortem at 24 h after injection of Venofer®, at doses of 10- and 40 mg/kg body weight (n?=?2?×?4), or saline (n?=?4).

Results

Within 10–20 min after injection of Venofer®, transverse relaxation rates (R₂) clearly increased, representative of a local increase in iron concentration, in liver, spleen and kidney, including the kidney medulla and cortex. In liver and spleen R₂ values remained elevated up to 3 h post injection, while the initial R₂ increase in the kidney was followed by gradual decrease towards baseline levels. Bone marrow and muscle tissue did not show significant increases in R₂ values. Whole-body post mortem MRI showed most prominent iron accumulation in the liver and spleen at 24 h post injection, which corroborated the in vivo results.

Conclusions

MR imaging is a powerful imaging modality for non-invasive assessment of iron distribution in organs. It is recommended to use this whole-body imaging approach complementary to other techniques that allow quantification of iron disposition at a (sub)cellular level.