Different Forms of TFF3 in the Human Endocervix, including a Complex with IgG Fc Binding Protein (FCGBP), and Further Aspects of the Cervico-Vaginal Innate Immune Barrier

TFF3 is a typical secretory poplypeptide of mucous epithelia belonging to the trefoil factor family (TFF) of lectins. In the intestine, respiratory tract, and saliva, TFF3 mainly exists as a high-molecular-mass complex with IgG Fc binding protein (FCGBP), which is indicative of a role in mucosal innate immunity. For the first time, we identified different forms of TFF3 in the endocervix, i.e., monomeric and homodimeric TFF3, as well as a high-molecular-mass TFF3-FCGBP complex; the latter also exists in a hardly soluble form. Immunohistochemistry co-localized TFF3 and FCGBP. Expression analyses of endocervical and post-menopausal vaginal specimens revealed a lack of mucin and TFF3 transcripts in the vaginal specimens. In contrast, genes encoding other typical components of the innate immune defense were expressed in both the endocervix and vagina. Of note, FCGBP is possibly fucosylated. Endocervical specimens from transgender individuals after hormonal therapy showed diminished expression, particularly of FCGBP. Furthermore, mucus swabs from the endocervix and vagina were analyzed concerning TFF3, FCGBP, and lysozyme. It was the aim of this study to illuminate several aspects of the cervico-vaginal innate immune barrier, which is clinically relevant as bacterial and viral infections are also linked to infertility, pre-term birth and cervical cancer.

Lecithin coating as universal stabilization and functionalization strategy for nanosized drug carriers to overcome the blood-brain barrier

Lecithin coated cholesteryl oleate (ChOl) based nanoparticles (NPs) imitating natural lipoproteins represent a new and promising drug carrier strategy to cross the blood-brain barrier (BBB). In such systems lecithin serves as stabilizing as well as functionalizing agent and enables the adsorptive binding of apolipoprotein E₃ (ApoE) as potential drug targeting ligand. The present work is focused on the effect of size reduction on the lecithin coating and ApoE binding. Furthermore, the transferability of this lecithin coating strategy to other NP cores, namely polylactic-co-glycolic acid (PLGA) and polylactic acid (PLA), is investigated in order to provide a universal strategy for a wide range of cores to overcome the BBB. The ChOl NPs' size was successfully reduced from 100 nm to 70 nm. Varying the core size of ChOl NPs illustrated, that the at least needed lecithin amount for sufficient stabilization could be calculated surface area dependently. However, the size reduction led to reduced dye loading per NP and increased ApoE need per NP mass. These effects turned out as huge disadvantages of smaller NPs by weakening the observed ApoE mediated effects. Nevertheless, the extended understanding of the lecithin coating could be used to transfer the concept to other core materials. PLGA and PLA NPs were investigated as alternative core materials for lecithin coating. PLGA was found to be unsuitable, whereas in the case of PLA sufficient stabilization and 100% adsorptive binding efficiency to ApoE could be achieved. The ApoE mediated effects of transcytosis at an in vitro BBB model by bypassing lysosomes were reproduced in even stronger quantities than with a ChOl core, proving lecithin coating as transferable strategy to disguise various NPs with a certain lipophilicity as lipoproteins.

Conversion of indomethacin nanosuspensions into solid dosage forms via fluid bed granulation and compaction

Preparation of pharmaceutical nanosuspensions is a popular technique to increase the dissolution velocity of poorly water-soluble drugs. Subsequent drying into a compaction-ready powder or granule is a critical process due to possible adverse solid characteristics and the risk of growth of nanoparticles. This work evaluated the drying of nanosuspensions via fluid bed granulation with focus on the binder selection and used concentrations, as well as the parameters spray rate and atomization pressure. Design of experiments was used to identify significant parameters. Indomethacin nanosuspensions were prepared by wet media milling and dried on a carrier consisting of lactose, microcrystalline cellulose, and crospovidone with and without additional binder during granulation. Resulting granules were compacted into tablets and their in vitro dissolution performances were characterized. A higher content of binder PVP and a higher spray rate led to less growth of resuspended nanoparticles. Finally, indomethacin nanoparticle tablets showed a superior dissolution performance in contrast to raw indomethacin tablets.

Asymmetrical flow field-flow fractionation for the analysis of PEG-asparaginase

Monomethoxypolyethylene glycol L-asparaginase (PEG-ASNASE) is the PEGylated version of the enzyme L-asparaginase (ASNASE). Both are used for remission induction in acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL). The treatment control is generally carried out by performing activity assays, though methods to determine the actual enzyme rather than its activity are rare. Using asymmetrical flow field-flow fractionation (AF4) offered the chance to develop a method capable of simultaneously measuring PEG-ASNASE and PEG. A method validation was performed in accordance with FDA guidelines for PEG-ASNASE from non-biological solutions. The method unfolded a linearity of 15-750 U/mL with coefficients of correlation of r(2)>0.99. The coefficients of variation (CV) for within-run and between-run variability were 1.18-10.15% and 2.43-8.73%, respectively. Furthermore, the method was used to perform stability tests of the product Oncaspar® (PEG-ASNASE) and estimation of the molecular weight by multi-angle light scattering (MALS) of stressed samples to correlate them with the corresponding activity. The findings indicate that Oncaspar® stock solution should not be stored any longer than 24 h at room temperature and cannot be frozen in pure aqueous media. The validated method might be useful for the pharmaceutical industry and its quality control of PEG-ASNASE production.

Plasma amino and keto acids in chronic renal failure

During both early and late stages of chronic renal insufficiency the response of BCKA to the disease state, as indicated by plasma levels, differs from that of BCAA. Val is the only BCAA whose concentration changes under the conditions of our study, and this only during the more advanced stages of disease. In contrast, all three BCKA declined, KIVA and KICA even in mild renal failure, showing that already during the early stages of the disease these BCKA levels are decreased. BCKA are more sensitive parameters than the corresponding amino acids with regard to the metabolic dysfunctions characteristic of this disease. Modern analytical methods allow more exact and reliable knowledge of these indicators and thus a better understanding of biochemical mechanisms, possibly resulting in better therapy.

PEGylated human serum albumin (HSA) nanoparticles: preparation, characterization and quantification of the PEGylation extent

Modification with poly(ethylene glycol) (PEG) is a widely used method for the prolongation of plasma half-life of colloidal carrier systems such as nanoparticles prepared from human serum albumin (HSA). However, the quantification of the PEGylation extent is still challenging. Moreover, the influence of different PEG derivatives, which are commonly used for nanoparticle conjugation, has not been investigated so far. The objective of the present study is to develop a method for the quantification of PEG and to monitor the influence of diverse PEG reagents on the amount of PEG linked to the surface of HSA nanoparticles. A size exclusion chromatography method with refractive index detection was established which enabled the quantification of unreacted PEG in the supernatant. The achieved results were confirmed using a fluorescent PEG derivative, which was detected by photometry and fluorimetry. Additionally, PEGylated HSA nanoparticles were enzymatically digested and the linked amount of fluorescently active PEG was directly determined. All the analytical methods confirmed that under optimized PEGylation conditions a PEGylation efficiency of up to 0.5 mg PEG per mg nanoparticle could be achieved. Model calculations made a 'brush' conformation of the PEG chains on the particle surface very likely. By incubating the nanoparticles with fetal bovine serum the reduced adsorption of serum proteins on PEGylated HSA nanoparticles compared to non-PEGylated HSA nanoparticles was demonstrated using sodium dodecylsulfate polyacrylamide gel electrophoresis. Finally, the positive effect of PEGylation on plasma half-life was demonstrated in an in vivo study in mice. Compared to unmodified nanoparticles the PEGylation led to a four times larger plasma half-life.

A microfluidic device for real-time monitoring of Bacillus subtilis bacterial spores during germination based on non-specific physicochemical interactions on the nanoscale level

A microfluidic device for studies on the germination of bacterial spores (e.g. Bacillus subtilis) based on non-specific interactions on the nanoscale is presented. A decrease in the population of spores during germination followed by the appearance of transition forms and an increase in the number of vegetative cells can be registered directly and simultaneously by using the microfluidic device, which is equipped with a conductive polymer layer (polyaniline) in the form of a nano-network. The lab-on-a-chip-type device, operating in a continuous flow regime, allows monitoring of germination of bacterial spores and analysis of the process in detail. The procedure is fast and accurate enough for quantitative real-time monitoring of the main steps of germination, including final transformation of the spores into vegetative cells. All of this is done without the use of biomarkers or any bio-specific materials, such as enzymes, antibodies and aptamers, and is simply based on an analysis of physicochemical interactions on the nanoscale level.

Individual day-to-day variations in plasma amino acid levels in healthy persons

Fasting plasma levels of the large neutral amino acids (LNAA;L-forms) andL-tryptophan (TRP) ratios were determined in thirteen healthy volunteers (7 males, 6 females) on five consecutive mornings, and the same procedure was repeated for each individual three months later. We found characteristic overall ranges for the parameters studied, and, in addition to certain differences between the sexes, considerable inter- and intraindividual daily variations. Although the individuals showed statistically identifiable mean levels that, in the majority of subjects, were maintained over a period of three months, it is concluded that the degree of intraindividual variability does not allow us to regard a single value as "characteristic" for a given individual. This should be borne in mind in particular in follow-up studies of plasma LNAA in patients with, for example, depressive disorders.

A note on mean distances, R̅[MO₆], in substituted polyhedra, [(M1-xMx′)O6], in the crystal structures of oxygen based solid solutions: local versus crystal averaging methods

Structure determination or refinement by diffraction methods on solid solutions containing more than one type of central ion in certain ployhedra of their crystal structures, e.g. (M1-xMx′)O6 octahedra, yield crystal-averaged mean distances R̅(M1-xMx′)-O depending on the site fraction x M′i of the substituting metal ion M′, which are equal or close to the interpolations between the mean distances in the respective and member polyhedra. However, such results represent virtual crystal approximations as they imply that no structural relaxation occurs to balance the different sizes of M and M′. Another extreme would be the hard sphere model, implying full structrual relaxation. In this case, R̅M-O and R̅M′-O retain the end member values independent of x M′i, and the results of the virtual crystal approximation obtained by diffraction methods, are to be interpreted as fractional distance sums x M′*R̅M′-O +(1-x M′)*R̅M-O. The real local situation is expected between these extremes, though the crystal averaging diffraction methods of structure research do not see that. This paper shows that the required local polyhedral distances in solid solutions in the case of substituitive 3dN transition metal ions, may be obtained by evaluating their crystal field parameters 10 Dq as extracted from their dd-transitons in electronic absorption spectra of the respective crystals. For this purpose, 10 Dq x M′ at a site fraction x M′i is to be extracted from measured spectra and reference values of (10 DqM′i)x=1 and (R̅(M′-O)i)x=1 in the M′-bearing end member of the solid solution series have to be known or measured. The evaluation of single crystal electronic spectra as well as of refinements of data from X-ray diffraction on crystals of a number of different 3dN-ion bearing solid solution series as viridine, piemonite, (Ni,Mg)-olivine, rubbies, (Fe,Mg)-chloritoid, prove that in all these cases R̅(M′-O)i strongly deviates from the virtual crystal approximation towards the fully relaxed situation of the real crystal. The lattice relaxations for infinite dilution, i.e. lim x M′i → 0, in corundum, andalusite, Mg-chloritoid and olivine are appreciable but do not strongly differ from each other, 0.52 < ε < 0.76. That the relaxation in corundum (ruby) is also in this range indicates that there is no strong compression of Cr3+-ions substituting for Al in this "hard structure".

The crystal chemistry of Mn3+ in the clino- and orthozoisite structure types, Ca2M3 3+[OH|O|SiO4|Si2O7]: A structural and spectroscopic study of some natural piemontites and “thulites” and their synthetic equivalents

Six new structure refinements and eleven sets of polarised, single-crystal electronic absorption spectra, E‖X, Y and Z, in the energy range 35000–5000 cm–1 were obtained on natural and synthetic orthozoisite-type “thulites” and clinozoisite-type piemontites: Ca2(Al3–pMp 3+) [OH|O|SiO4|Si2O7] where M3+ = Mn3+ or (Mn1–n 3+Fen 3+) for the synthetic or natural minerals, respectively. Electron microprobe analyses of the single crystals studied revealed substitutional degrees pM3+ = 0.13 or 0.51 in natural and synthetic “thulite”, respectively, and 0.57 ≤ pM3+ ≤ 1.17 or 0.83 ≤ pM3+ ≤ 1.47 in the natural or synthetic piemontites, respectively.

Manganese in “thulite” is trivalent, as it is in piemontite. In both structure types, M3+ fractionates strongly into the axially compressed [M(3)O6] polyhedra, and does not enter the M(2) sites. Mean M(3)—O and M(1)—O distances increase in both structures, compared to the M3+-free Al end members. Such distance changes in piemontite are +0.47% and +0.53% per 0.1x M3+, respectively, (x = site fraction). The bending angle of the Si2O7-group in cis-configuration, ∢Si(1)—O(9)—Si(2), decreases from 164.4° in clinozoisite to 147.4° in the most Mn3+-rich synthetic piemontite with p Mn³⁺ = 1.47 (emp) or x Mn³⁺(M3) = 0.931 and x Mn³⁺(M1) = 0.460 (from structure refinement).

The detailed evaluation of the changes, due to Al→M3+ substitution, of individual bond lengths, as well as the quantitative evaluation of the intensities of the strong spinallowed dd bands of Mn3+ in M(3), prove that in natural piemontite the preference of Mn3+ for M(3) over M(1) is more pronounced than that of Fe3+. This is in accord with the Jahn-Teller effect of 3d4-configurated Mn3+. In addition, evaluation of the individual M(3)–O(i) distances with increasing x Mn³⁺(M3) in piemontite indicates that the axial compression of the [M(3)O6] polyhedra increases. This contrasts with the behaviour of Fe3+-bearing epidotes and is again in accord with the Jahn-Teller effect of Mn3+.

The polarisation behaviour of the three strong spin-allowed dd-bands of Mn3+ in M(3), v I at 13000–12000 cm–1 (E‖Y), v II at 19000–18000 cm–1 (E‖Y and Z, Z > Y) and v III at 24000–22000 cm–1 (E‖X) is best interpreted by assuming a C 2 v (C 2″) pseudo-symmetry of the M(3) sites, a super-group of their site symmetry Cs . Evaluation of the energies of v I, v II and v III on the basis of the energy level diagram obtained for Mn3+ with the above pseudo-symmetry yields the crystal field parameter 10 Dq = 13540 cm–1 for x Mn³⁺(M3) = 0:931. 10 Dq increases slightly by 30 cm–1 per -0.1x Mn³⁺(M3). Such values and the Jahn-Teller splitting of the octahedral crystalfield ground-state of Mn3+, δ = v I, yield a crystal field stabilisation energy of Mn3+(M3) of 14080 cm–1 for x Mn³⁺(M3) = 0:931. CFSEMn 3+ increases slightly by 28 cm–1 per -0.1x Mn³⁺(M3). Such values are appreciably smaller than those typical of Mn3+ substituting for Al in the axially elongated [M(1)O6] octahedra in the andalusite structure type. This different behaviour of Mn3+ in the two structure types is likely due to the smaller deviation of (c=a)oct in piemontite M(3) compared to andalusite M(1) for the same site fractions of Mn3+. In addition, the axial inversion effect — compressed [M(3)O6] in the clinozoisite-type or elongated [M(1)O6] in the andalusite-type, involving the electron hole of 3d4 in d z 2 or d( x ²- y ²), respectively — may play a role.

The crystal chemistry of the humite minerals: spectroscopic studies and structure refinement of an unusual iron-rich clinohumite

An orange-red mineral with strong pleochroism from magnesian skarns of the Salminski rapakivi massif which was originally described as an olivine,is identified as an unusually iron-rich clinohumite.The composition of the mineral is,as obtained by combining data of electron microprobe analyses,Mössbauer analyses and unconstrained structure refinements: [Mg5.2(Fe3.42 2+Mn0.07Ni0.01Zn0.04Ca0.01Fe0.11 3+ Ti0.04 4+)Σ=3.70] × [Si4.03O16[F1.21(OH,O)0.79]Σ=2.00]. Thus,the Fe-end member fraction is X Fe = 0.42, i.e. unusually high when compared with those of the usual magnesian clinohumites, e.g. = 0.06 in the crystal studied structurally by Robinson et al.(1973). Fe is the sumof octahedral,Mg-substituting cations which could - due to the similarity of their scattering curves and the very low fractions except for that of iron - not be discriminated in the structure refinement. Such refinements yield the following Fe-fractionations, f Fe, between the different octahedral sites of the structure: f Fe(M1 c ) =0.17, f Fe(M1 n ) = 0.33, f Fe(M26) = 0.32, f Fe(M25) = 0.13, f Fe(M3) = 0.05 (ΣFe = 1.00). The analysis of the Mössbauer spectra yields a fractionation pattern very close to that obtained by XRD. The Fe-fractioning in the ferrous clinohumite with X Fe = 0.42 is nearly the same as that in magnesian clinohumite with X Fe = 0.06, such similarities being obviously related to the fact that a slightly distorted hexagonally close anion package forms the basis of all the humite mineral structures. The structural changes on iron incorporation pertain predominantely changes in the individual and mean M–O distances and O–M–O angles. Polyhedral distortions Δ oct and σ oct 2 increase most drastically, compared to magnesian clinohumite with X Fe = 0.06, in the M26 octahedra. The polarized electronic absorption spectra are dominated by two features: an intense, broad band centered at 22800 cm-1 strongly polarized E ∥ X (nα ∢ b ca. 10°), which was identified as Fe2+(M25)-Ti4+(M3) charge-transfer transition in the M25M3M3M25 octahedral chain fragments of the structure. The strong polarization of this band together with the position of the UV absorption edge,causes the pleochroismof the mineral.The second prominent feature in the polarized single crystal spectra is a complex band system in the NIR which is assigned to dd-transitions of Fe2+(M1 c + M1 n ), bands at 10800 and 7600 cm-1, and of Fe2+(M26), bands at 9400 and 8800 cm-1. Such transitions are in analogy with the behaviour of Fe2+ in the M1 and M2 sites of the olivine structure.

Lung injury following thoracic aortic occlusion: comparison of sevoflurane and propofol anaesthesia

BACKGROUND

Halogenated anaesthetics have been shown to reduce ischaemia-reperfusion injuries in various organs due to pre- and post-conditioning mechanisms. We compared volatile and total intravenous anaesthesia with regard to their effect on remote pulmonary injury after thoracic aortic occlusion and reperfusion.

METHODS

Eighteen pigs were randomized after sternotomy and laparotomy (fentanyl-midazolam anaesthesia) to receive either sevoflurane or propofol in an investigator-blinded fashion. Ninety minutes of thoracic aortic occlusion was induced by a balloon catheter. During reperfusion, a goal-directed resuscitation protocol was performed. After 120 min of reperfusion, the anaesthetic regimen was changed to fentanyl-midazolam again for another 180 min. The oxygenation index and intra-pulmonary shunt fractions were calculated. After 5 h of reperfusion, a bronchoalveolar lavage was performed. The total protein content and lactate dehydrogenase activity were measured in epithelial lining fluid (ELF). Alveolar macrophage oxidative burst was analysed. The wet to dry ratio was calculated and tissue injury was graded using a semi-quantitative score. Ten animals (n=5 for each anaesthetic) without aortic occlusion served as time controls.

RESULTS

The oxygenation index decreased and the intra-pulmonary shunt fraction increased significantly in both occlusion groups. There were no significant differences between sevoflurane and propofol with respect to the oxygenation index, ELF composition, morphologic lung damage, wet to dry ratio and alveolar macrophage burst activity. Differences were, however, seen in terms of systemic haemodynamic stability, where catecholamine requirements were less pronounced with sevoflurane.

CONCLUSION

We conclude that the severity of remote lung injury was not different between sevoflurane and propofol anaesthesia in this porcine model of severe lower-body ischaemia and reperfusion injury.

Continuous subcutaneous insulin infusion leads to immediate, stable and long-term changes in metabolic control

BACKGROUND

Evaluations of continuous subcutaneous insulin infusion (CSII) usually focus on one pre- and one post-CSII measurement to assess metabolic therapy outcome.

AIM

Extending this research, the aim of the present study was to provide a more fine-grained analysis of achieved glycaemic control.

METHODS

In 52 patients with type 1 diabetes (mean age of 37.85 years at CSII begin; s.d. +/- 12.41), haemoglobin A(1c) (HbA(1c)) levels were assessed every 3 months over a period of 5 years (1 year before and 4 years after the introduction of CSII). Mixed models were utilized to describe changes in glycaemic control.

RESULTS

The pre-post course showed that already in the first quarter, a statistically significant lower HbA(1c) level was obtained [7.30%, in contrast to 8.21% at the last quarter with intensified conventional therapy (ICT)]. In the following 15 quarters, the mean HbA(1c) levels remained constantly lower than that with ICT. Overall, the aggregated mean HbA(1c) level of patients with CSII therapy was 7.19%, in contrast to 8.08% with ICT; thus, an overall decrease by 11% was achieved. In addition, individual differences in blood glucose level and age of diabetes onset as a predictor for therapy success were analysed.

CONCLUSIONS

The data show an immediate, stable and long-term effect of CSII on HbA(1c). In addition, a significant relationship between metabolic control and age of diabetes onset was found, as well as a reduction of variance in HbA(1c) levels between subjects after change to CSII.

Human serum albumin (HSA) nanoparticles: Reproducibility of preparation process and kinetics of enzymatic degradation

Nanoparticles prepared from human serum albumin (HSA) are versatile carrier systems for drug delivery and can be prepared by an established desolvation process. A reproducible process with a low batch-to-batch variability is required for transfer from the lab to an industrial production. In the present study the batch-to-batch variability of the starting material HSA on the preparation of nanoparticles was investigated. HSA can build dimers and higher aggregates because of a free thiol group present in the molecule. Therefore, the quality of different HSA batches was analysed by size exclusion chromatography (SEC) and analytical ultracentrifugation (AUC). The amount of dimerised HSA detected by SEC did not affect particle preparation. Higher aggregates of the protein detected in two batches by AUC disturbed nanoparticle formation at pH values below 8.0. At pH 8.0 and above monodisperse particles between 200 and 300 nm could be prepared with all batches, with higher pH values leading to smaller particles. Besides human derived albumin a particle preparation was also feasible based on recombinant human serum albumin (rHSA). Under comparable preparation conditions monodisperse nanoparticles could be achieved and the same effects of protein aggregates on particle formation were observed. For nanoparticulate drug delivery systems the enzymatic degradation is a crucial parameter for the release of an embedded drug. For this reason, besides the particle preparation process, particle degradation in the presence of different enzymes was studied. Under acidic conditions HSA as well as rHSA nanoparticles could be digested by pepsin and cathepsin B. At neutral pH trypsin, proteinase K, and protease were suitable for particle degradation. It could be shown that the kinetics of particle degradation was dependent on the degree of particle stabilisation. Therefore, the degree of particle stabilisation will influence drug release after cellular accumulation of HSA nanoparticles.

Influence of the formulation on the tolerance profile of nanoparticle-bound doxorubicin in healthy rats: Focus on cardio- and testicular toxicity

A toxicological study of doxorubicin bound to poly(butyl cyanoacrylate) or human serum albumin nanoparticles coated with polysorbate 80 was performed in healthy rats. The doxorubicin formulations were injected at a therapeutic dose regimen (3 x 1.5 mg/kg with a 72 h interval), and the animals were followed up for 15 or 30 days. The overall result of this study suggests that the surfactant-coated nanoparticle formulations of doxorubicin have favorable toxicological profiles. Specifically, these formulations display a considerably reduced cardio- and testicular toxicity, as compared to a free drug.

Barrier function of the gut and multiple organ dysfunction after cardiac surgery

We studied the influence of sequential involvement of the gastrointestinal (GI) tract on the development of multiple organ dysfunction (MOD) after cardiopulmonary bypass (CPB). One hundred and forty-six patients undergoing elective cardiac surgery were included in this prospective observational study. Standardized oral inert-sugar tests (sucrose, lactulose, mannitol, sucralose) were performed before and after CPB in different patients. Enzyme-linked immunosorbent assay of plasma levels of endotoxin core antibodies (EndoCAb) were performed peri-operatively. The functional mucosal surface was calculated from the amount of mannitol absorbed from the GI tract. Lower urine concentrations of absorbed mannitol were observed pre-operatively in patients developing MOD. In binary logistic regression this was an independent parameter. Decreased plasma concentrations of EndoCAb after surgery were seen in every patient, but were more significant in patients developing MOD. A reduced pre-operative functional mucosal surface may predict the early occurrence of MOD after surgery.

Effects of sevoflurane and propofol on ischaemia–reperfusion injury after thoracic-aortic occlusion in pigs

BACKGROUND

Thoraco-abdominal-aneurysm surgery predicts high mortality. Propofol and sevoflurane are commonly used anaesthetics for this procedure. Halogenated anaesthetics induce organ protection similar to ischaemic preconditioning. We investigated which anaesthetic regimen would lead to a better protection against ischaemia-reperfusion injury induced by temporary thoracic-aortic occlusion.

METHODS

Following initial fentanyl-midazolam anaesthesia for surgical preparation, 18 pigs were randomly assigned to two groups: group one received propofol (n=9) and group two sevoflurane (n=9) before, during, and after lower body ischaemia in an investigator blinded fashion. Ten animals without aortic occlusion served as time controls (propofol, n=5; sevoflurane, n=5). For induction of ischaemia, the thoracic aorta was occluded by a balloon-catheter for 90 min. After 120 min of reperfusion, the study anaesthetics were discontinued and fentanyl-midazolam re-established for an additional 180 min. Goal-directed therapy was performed during reperfusion. Fluid and catecholamine requirements were assessed. Serum samples and intestinal tissue specimens were obtained.

RESULTS

Severe declamping shock occurred in both study groups. While norepinephrine requirements in the sevoflurane group were significantly reduced during reperfusion (P<0.05), allowing cessation of catecholamine support in 4/9 animals, all 9/9 animals were still catecholamine dependent at the end of the experiment in the propofol group. Serum activities of lactate dehydrogenase, aspartate transaminase, and alanine aminotransferase were lower with sevoflurane (P<0.05). Small intestine tissue specimens did not differ histologically.

CONCLUSIONS

Use of sevoflurane compared with propofol attenuated the haemodynamic sequelae of reperfusion injury in our model. Release of serum markers of cellular injury was also attenuated.

Preparation, characterisation and maintenance of drug efficacy of doxorubicin-loaded human serum albumin (HSA) nanoparticles

Human serum albumin (HSA) nanoparticles represent promising drug carrier systems. Binding of cytostatics to HSA nanoparticles may diminish their toxicity, optimise their body distribution and/or may overcome multidrug resistance. In the present study, doxorubicin-loaded HSA nanoparticle preparations were prepared. Doxorubicin was loaded to the HSA nanoparticles either by adsorption to the nanoparticles' surfaces or by incorporation into the particle matrix. Both loading strategies resulted in HSA nanoparticles of a size range between 150nm and 500nm with a loading efficiency of 70-95%. The influence on cell viability of the resulting nanoparticles was investigated in two different neuroblastoma cell lines. The anti-cancer effects of the drug-loaded nanoparticles were increased in comparison to doxorubicin solution. Based on these result a standard protocol for the preparation of doxorubicin-loaded HSA nanoparticles for further antitumoural studies was established.

Circulating levels of brain-derived neurotrophic factor correlate with disease severity in the intrinsic type of atopic dermatitis

BACKGROUND

Recent studies have shed light on the complex regulation of genetic, environmental, immunologic and pharmacologic factors, which contribute to the development of atopic dermatitis (AD). However, it is still unclear to which extent neuroimmune mediators have a role in AD.

AIMS OF THE STUDY

To assess peripheral neurotrophin levels and their correlation with scoring atopic dermatitis (SCORAD) scores in both the intrinsic and extrinsic types of AD compared with patients with psoriasis and nonatopic healthy subjects.

METHODS

Levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) were assessed in peripheral blood with enzyme-linked immunosorbent assay. Based on IgE-mediated sensitization, AD was divided into the extrinsic and intrinsic type. Severity of AD was assessed with SCORAD score and with psoriasis area and severity index (PASI) in patients with psoriasis.

RESULTS

Brain-derived neurotrophic factor and NGF were detectable in all the subjects studied. However, the levels of both neurotrophins were significantly higher in patients with extrinsic and intrinsic types of AD compared with patients with psoriasis and nonatopic healthy subjects (NGF: P < 0.001, BDNF: P < 0.001). NGF and BDNF levels were similar in the intrinsic and extrinsic type of AD. There was a significant correlation between BDNF and SCORAD score only in patients with the intrinsic type of AD (r = 0.57, P < 0.05).

CONCLUSIONS

This study shows for the first time that NGF and BDNF are increased in both, the extrinsic type and the intrinsic type of AD. This finding points to a similar pathophysiologic background implicating a neuroimmune network in both variants of this chronic inflammatory skin disease. Future studies are needed to show the direct mechanisms of neurotrophin action in chronic inflammatory skin.

Covalent Linkage of Apolipoprotein E to Albumin Nanoparticles Strongly Enhances Drug Transport into the Brain

Drug delivery to the brain is becoming more and more important but is severely restricted by the blood-brain barrier. Nanoparticles coated with polysorbates have previously been shown to enable the transport of several drugs across the blood-brain barrier, which under normal circumstances is impermeable to these compounds. Apolipoprotein E was suggested to mediate this drug transport across the blood-brain barrier. In the present study, apolipoprotein E was coupled by chemical methods to nanoparticles made of human serum albumin (HSA-NP). Loperamide, which does not cross the blood-brain barrier but exerts antinociceptive effects after direct injection into the brain, was used as model drug. Apolipoprotein E was chemically bound via linkers to loperamide-loaded HSA-NP. This preparation induced antinociceptive effects in the tail-flick test in ICR mice after i.v. injection. In contrast, nanoparticles linked to apolipoprotein E variants that do not recognize lipoprotein receptors failed to induce these effects. These results indicate that apolipoprotein E attached to the surface of nanoparticles facilitates transport of drugs across the blood-brain barrier, probably after interaction with lipoprotein receptors on the brain capillary endothelial cell membranes.

Incorporation of biodegradable nanoparticles into human airway epithelium cells-in vitro study of the suitability as a vehicle for drug or gene delivery in pulmonary diseases

PURPOSE

Nanoparticles are able to enhance drug or DNA stability for purposes of optimised deposition to targeted tissues. Surface modifications can mediate drug targeting. The suitability of nanoparticles synthesised out of porcine gelatin, human serum albumin, and polyalkylcyanoacrylate as drug and gene carriers for pulmonary application was investigated in vitro on primary airway epithelium cells and the cell line 16HBE14o-.

METHODS

The uptake of nanoparticles into these cells was examined by confocal laser scan microscopy (CLSM) and flow cytometry (FACS). Further the cytotoxicity of nanoparticles was evaluated by an LDH-release-test and the inflammatory potential of the nanoparticles was assessed by measuring IL-8 release.

RESULTS

CLSM and FACS experiments showed that the nanoparticles were incorporated into bronchial epithelial cells provoking little or no cytotoxicity and no inflammation as measured by IL-8 release.

CONCLUSIONS

Based on their low cytotoxicity and the missing inflammatory potential in combination with an efficient uptake in human bronchial epithelial cells, protein-based nanoparticles are suitable drug and gene carriers for pulmonary application.

Optimization of the preparation process for human serum albumin (HSA) nanoparticles

Nanoparticles prepared by desolvation and subsequent crosslinking of human serum albumin (HSA) represent promising carriers for drug delivery. Particle size is a crucial parameter, in particular for the in vivo behaviour of nanoparticles after intravenous injection. The objective of the present study is the development of a desolvation procedure for the preparation of HSA-based nanoparticles under the aspect of a controllable particle size between 100 and 300 nm in combination with a narrow size distribution. A pump-controlled preparation method was established which enabled particle preparation under defined conditions. Several factors of the preparation process, such as the rate of addition of the desolvating agent, the pH value and the ionic composition of the HSA solution, the protein concentration, and the conditions of particle purification were evaluated. The pH value of the HSA solution prior to the desolvation procedure was identified as the major factor determining particle size. Varying this parameter, (mean) particle diameters could be adjusted between 150 and 280 nm, higher pH values leading to smaller nanoparticles. Washing the particles by differential centrifugation led to significantly narrower size distributions. The reproducibility of the particle size and particle size distribution under the proposed preparation conditions was demonstrated by sedimentation velocity analysis in the analytical ultracentrifuge and the cellular uptake of those nanoparticles was studied by confocal microscope imaging and FACS analysis. The stability of the resulting nanoparticles was evaluated by pH and buffer titration experiments. Only pH values distinctly outside the isoelectric pH range of HSA and low salt concentrations were able to prevent nanoparticle agglomeration.

Glutamine distribution in patients with ulcerative colitis and in patients with familial adenomatous polyposis coli before and after restorative proctocolectomy

BACKGROUND AND AIMS

Restorative proctocolectomy with construction of an ileoanal pouch (IPAA) is the surgical treatment of choice for patients with ulcerative colitis (UC) or familial adenomatous polyposis (FAP). This procedure imposes an essential change in function on the terminal ileal mucosa and pouch mucosa. Glutamine is one of the major nutrients for the small-bowel mucosa; it is metabolized into glutamate and subsequently alanine in the human enterocyte. In a prospective clinical trial we compared glutamine distribution in patients with UC to that in patients with FAP before and after restorative proctocolectomy.

METHODS AND PATIENTS

Concentrations of glutamine, glutamate, and alanine were measured pre- and postoperatively in the terminal ileal mucosa, pouch mucosa, skeletal muscle and venous blood of patients undergoing IPAA for UC or FAP. Healthy individuals served as controls for skeletal muscle glutamine concentration.

RESULTS

After IPAA the glutamine concentration in UC patients was decreased in skeletal muscle. In the mucosa glutamine remained unaltered while glutamate and alanine concentrations increased. In plasma the glutamine concentration increased, the glutamate level fell, and the alanine level increased. In FAP patients the glutamine level was unchanged in skeletal muscle after IPAA. In mucosa the glutamine level did not change, but glutamate and alanine increased. In plasma the glutamine level remained unaltered, glutamate decreased, and alanine increased.

CONCLUSION

Patients with UC or FAP before surgical therapy do not suffer from glutamine depletion. IPAA resulted in changes in the distribution of glutamine and its metabolites in skeletal muscle, plasma, and ileal pouch mucosa, particularly in patients with UC. Further studies should investigate whether characteristics in the glutamine distribution have any impact for the long-term outcome after IPAA.

Preparation of surface modified protein nanoparticles by introduction of sulfhydryl groups

The objective of the present study was to establish several methods for the introduction of thiol groups onto the surface of human serum albumin (HSA) nanoparticles. Besides the epsilon-amino groups of lysine, the carboxyl groups of asparaginic and glutaminic acid, and the carbonyl groups of the cross-linker glutaraldehyde, sulfhydryl groups are possible targets for the covalent linkage of drugs to particle surfaces. In principle, the thiol groups were introduced by the reaction with dithiotreitol (DDT) or 2-iminothiolane, by quenching reactive aldehyde residues with cystaminiumdichloride or by coupling L-cysteine and cystaminiumdichloride by the aqueous carbodiimide reaction. The resulting nanoparticulate systems were characterised concerning the number of available sulfhydryl groups, particle size and particle density. It was shown, that by variation of the reaction conditions, e.g., the concentration of the coupling reagent or the sulfhydryl containing component as well as the reaction time, the proposed methods enabled the preparation of HSA nanoparticles with a well defined surface characteristic. Stability studies showed that the introduced thiol groups were relatively stable and lost their reactivity with a half-life of 28.2 days independently of the method used for the sulfhydryl group introduction. Besides the quantification of free sulfhydryl groups the covalent attachment of cystaminiumdichloride by the carbodiimide reaction was used to calculate the amount of free carboxyl groups on the surface of the nanoparticles. The toxicity of the modified nanoparticles was evaluated in cell culture experiments.

Cytotoxicity of aphidicolin and its derivatives against neuroblastoma cells in vitro: synergism with doxorubicin and vincristine

Disseminated neuroblastoma diseases are still indicated by a poor outcome despite treatment regimens including radiation therapy and high-dose chemotherapy with stem cell rescue. Therefore, new substances and treatment regimens are of interest. Aphidicolin (APH), a tetracyclic diterpene antibiotic produced by Cephalosporium aphidicola, has a specific toxicity for neuroblastoma cells. Furthermore, it was shown to enhance the effects of X-ray radiation and chemotherapy on malignant cells. To find new substances, 20 APH derivatives were tested for their anti-neuroblastoma efficacy in vitro in UKF-NB-2 cells. Five derivatives had antitumoral activity in neuroblastoma cells. A relationship between the structure and the antitumoral efficacy showed that the hydroxyl groups at C-3 and C-18 are essential for the antitumoral effects. Furthermore, antitumoral effects of APH in combination with doxorubicin and vincristine, both part of commonly used treatment regimens for disseminated neuroblastoma diseases, were tested in the neuroblastoma cell line UKF-NB-2. APH was found to act synergistically with vincristine and synergistically to additive with doxorubicin depending on the molecular ratio of the substances in combination. This may offer the chance to use APH and its derivatives as additional tools in the treatment of neuroblastomas.

Glycyl-glutamine improves in vitro lymphocyte proliferation in AIDS patients

BACKGROUND

Glutamine (Gln) is a major nutrient for rapidly proliferating cells. Unlike glutamine itself, the dipeptide glycyl-glutamine as a source for Gln is stable in aqueous solutions ex vivo. In order to evaluate the possible therapeutic role of glycyl-glutamine on lymphocyte proliferation we investigated its influence on lymphocytes of AIDS patients and healthy controls under stimulation with different mitogens.

MATERIAL AND METHODS

Lymphocytes were collected from 11 adult patients suffering from AIDS according to the CDC definition and from 7 adult healthy donors. Glutamine (Gln) and glycyl-glutamine (GlyGln), respectively, were added to cell cultures at concentrations between 0 and 1.0 mmol/l. ConA or SAC served as T or B cell mitogens, respectively. Plasma amino acid levels were determined.

RESULTS

Proliferation upon ConA-stimulation with GlyGln-supplementation was similar to Gln-supplementation and peaked dose dependently at 1.0 mmol/l. When SAC was used Gln seemed slightly superior to GlyGln with a peak at 0. 4 mmol/l but the results did not reach the level of statistical significance. An identical response pattern was demonstrated in HIV-patients, however at lower absolute proliferation rates. Normal values could not be restored. Overall, the use of either source of glutamine in equimolar concentrations did not result in major differences of proliferation. Glutamine and glycin plasma levels did not differ between HIV patients and controls.

CONCLUSION

GlyGln can be used as a substitute for Gln with regard to lymphocyte proliferation. Lymphocytes from AIDS patients show, as controls do, an enhanced proliferation under supplementation either glutamine source. Supplementation of GlyGln might enhance lymphocyte proliferation and thus improve immunity.

Bovine seminal ribonuclease attached to nanoparticles made of polylactic acid kills leukemia and lymphoma cell lines in vitro

Bovine seminal ribonuclease (BS-RNase) is a protein with a number of biological effects. It shows antitumoral, aspermatogenic, antiembryonic, immunosuppressive and antiviral properties. The cytotoxic effects appear to be specific for tumor cells as non-malignant cells seem to be unaffected in vitro. Unfortunately, the in vivo application of BS-RNase so far was successful only when it was administered intratumorally. Therefore, the objective of the present investigation was to improve the properties of BS-RNase by attachment to nanoparticles made of polylactic acid (PLA-NP) using an adsorption method. This preparation was tested in vitro against leukemia (MOLT-4) and lymphoma (H9) cell lines sensitive and resistant to cytarabine. No difference between the nanoparticle preparation and pure BS-RNase was found in these tests. To examine the in vivo effects, the preparations were tested for their aspermatogenic and antiembryonal efficacy compared to the pure BS-RNase as a rapid test for antitumoral activity. The aspermatogenic and antiembryonal effects were enhanced by the nanoparticle preparation. Consequently, BS-RNase loaded adsorptively to PLA-NP holds promise for the in vivo use as an antitumoral agent. Further research will investigate the efficacy of this preparations in an in vivo tumor model.

Preparation of avidin-labeled protein nanoparticles as carriers for biotinylated peptide nucleic acid

The possibility of preparing protein nanoparticles followed by covalent linkage of avidin was investigated. Free sulfhydryl groups were introduced onto the surface of protein nanoparticles either by aldehyde quenching with cysteine or reaction of free amino groups with 2-iminothiolane. The number of primary amino groups and sulfhydryl groups on the surface of the resulting particles was quantified with site-specific reagents. Avidin was attached to the surface of the thiolated nanoparticles via a bifunctional spacer which reacted in a first step with amino groups of avidin and in a second step with the sulfhydryl groups introduced onto the surface of the nanoparticles. Biotinylated peptide nucleic acid (PNA) as a model compound for biotinylated drugs was effectively coupled to the nanoparticles by complex formation with the covalently attached avidin. Since the formation of the interaction between biotin and avidin is very rapid and stable a highly effective drug carrier system for biotinylated compounds such as PNAs was achieved.

Preparation of avidin-labelled gelatin nanoparticles as carriers for biotinylated peptide nucleic acid (PNA)

The possibility of preparing uniform nanoparticles consisting of proteins such as gelatin followed by covalent linkage of avidin was investigated. Gelatin nanoparticles were prepared by two step desolvation. Functional groups at the surface of the particulate system were quantified with site-specific reagents. The surface of the nanoparticles was thiolated and avidin was covalently attached to the nanoparticles via a bifunctional spacer at high levels. Biotinylated peptide nucleic acid (PNA) was effectively complexed by the avidin-conjugated nanoparticles. Avidin-conjugated protein nanoparticles should prove as potential carrier system for biotinylated drug derivatives in antisense therapy.

Desolvation process and surface characteristics of HSA-nanoparticles

The objective of the present study was to characterise and optimise the desolvation process of human serum albumin (HSA) for the preparation of nanoparticles. Following the desolvation of the protein, the resulting nanoparticles were stabilised by the addition of varying amounts of glutaraldehyde. The particle size and the number of available amino groups on the surface of the nanoparticles were determined. The results indicated that the particle size depended mainly on the amount of desolvating agent added, but not on the amount of cross-linker. Increasing volumes of glutaraldehyde reduced the number of amino groups on the surface of HSA nanoparticles.

Gelatin nanoparticles by two step desolvation--a new preparation method, surface modifications and cell uptake

A new two-step desolvation method for manufacturing gelatin nanoparticles was developed. After the first desolvation step, the low molecular gelatin fractions present in the supernatant were removed by decanting. The high molecular fractions present in the sediment were redesolved and then desolvated again at pH 2.5 in the second step. The resulting particles can then be easily purified by centrifugation and redispersion. The different fractions obtained during the process were analysed by gel permeation chromatography (GPC). Based on these results, it can be concluded that the molecular weight of gelatin has a decisive influence on the stability of the manufactured gelatin nanoparticles. In addition, two fluorescent dyes (Texasred and fluoresceinamine) were coupled to the nanoparticles for cell uptake studies. The fluorescent nanoparticles showed a high uptake into monocytes/macrophages.