Gas Chromatography-Mass Spectrometry Detection of Thymoquinone in Oil and Serum for Clinical Pharmacokinetic Studies

Thymoquinone (TQ) is the primary component of Nigella sativa L. (NS) oil, which is renowned for its potent hepatoprotective effects attributed to its antioxidant, anti-fibrotic, anti-inflammatory, anti-carcinogenic, and both anti- and pro-apoptotic properties. The aim of this work was to establish a method of measuring TQ in serum in order to investigate the pharmacokinetics of TQ prior to a targeted therapeutic application. In the first step, a gas chromatography-mass spectrometry method for the detection and quantification of TQ in an oily matrix was established and validated according to European Medicines Agency (EMA) criteria. For the assessment of the clinical application, TQ concentrations in 19 oil preparations were determined. Second, two serum samples were spiked with TQ to determine the TQ concentration after deproteinization using toluene. Third, one healthy volunteer ingested 1 g and another one 3 g of a highly concentrated NS oil 30 and 60 min prior to blood sampling for the determination of serum TQ level. After the successful establishment and validation of the measurement method, the highest concentration of TQ (36.56 g/L) was found for a bottled NS oil product (No. 1). Since a capsule is more suitable for oral administration, the product with the third highest TQ concentration (No. 3: 24.39 g/L) was used for all further tests. In the serum samples spiked with TQ, the TQ concentration was reliably detectable in a range between 5 and 10 µg/mL. After oral intake of NS oil (No. 3), however, TQ and/or its derivatives were not detectable in human serum. This discrepancy in detecting TQ after spiking serum or following oral ingestion may be attributed to the instability of TQ in biomatrices as well as its strong protein binding properties. A pharmacokinetics study was therefore not viable. Studies on isotopically labeled TQ in an animal model are necessary to study the pharmacokinetics of TQ using alternative modalities.

[Benign liver tumors : Diagnostics and treatment]

Benign liver tumors are often detected during routine ultrasound examinations or as an incidental finding in radiological imaging. Only very few benign liver tumors are at risk of becoming malignant. In the majority of cases the differentiation from malignant tumors is currently carried out using imaging procedures. In a few cases of diagnostic uncertainty, a transcutaneous liver biopsy can lead to clarification. If the suspicion of malignancy is substantiated or this cannot be excluded with absolute certainty, the tumor should be removed by partial liver resection.

[Knowledge, trust, and the decision to donate organs : A comparison of medical students and students of other disciplines in Germany]

BACKGROUND

Following the organ transplant scandal in Germany in 2011, the willingness to donate organs postmortem decreased dramatically. This was explained by a loss of confidence in the German organ donation system.

OBJECTIVES

The aim of this study was to evaluate the relationship between knowledge, trust, and fear in respect to organ donation and the explicit willingness to potentially act as an organ donor by comparing medical students to students of other disciplines.

MATERIAL AND METHODS

We conducted a Facebook-based online survey (June-July 2013). The participating students were divided into two groups according to their discipline: medical students and other students. Based on questions covering different aspects of organ donation, a knowledge, trust, and fear score was established and calculated. The answers were related to an explicitly expressed decision to donate organs as expressed in a signed organ donor card.

RESULTS

In total, 2484 participants took part in our survey. Of these, 1637 were students, 83.7% (N = 1370) of which were medical students and 16.3% (N = 267) other students. As expected, medical students reached a higher knowledge score regarding organ donation compared with other students (knowledge score 4.13 vs. 3.38; p < 0.001). They also demonstrated more confidence in organ donation, resulting in a higher confidence score (3.94 vs. 3.33; p < 0.001) and expressed less fear towards organ donation as indicated by the lower fear score (1.76 vs. 2.04; p < 0.01). Medical students declared their written willingness to donate organs more often than did other students (78.2% vs. 55.2%; p < 0.001). Entries on organ donation cards did not differ significantly between medical students and other students. Medical students possessing an organ donor card showed a higher knowledge and a higher trust score than did medical students without an organ donor card. In contrast, other students possessing an organ donor card showed a higher trust score but did not show a higher knowledge score.

CONCLUSIONS

The higher level of knowledge and trust demonstrated by the medical students was associated with a higher rate of written decisions to donate organs. In contrast, the lower level of knowledge and trust observed in the non-medical students was associated with a lower rate of organ donor cards. Interestingly, in the group of non-medical students, the decision regarding organ donation was associated with a higher level of trust, but not with a higher level of knowledge. It would appear that knowledge, trust, and the decision to donate organs are closely related. In cases of a low level of knowledge, confidence is even more important. Therefore, organ donation campaigns should focus on increasing knowledge and fostering trust.

[Liver engineering as a new source of donor organs : A systematic review]

BACKGROUND

Organ engineering is a new strategy to cope with the shortage of donor organs. A functional scaffold from explanted organs is prepared by removing all cellular components (decellularization) and the reseeding (repopulation) of the organ scaffold to generate a functional organ in vitro for transplantation. This technique was also applied to the liver (liver engineering).

OBJECTIVES

Outline of the current state of the art and resulting approaches for future research strategies.

MATERIAL AND METHODS

Systematic review according to the PRISMA guidelines: a PubMed-based literature search (search terms liver, decellularization), selection of relevant articles based on predetermined criteria for relevance (e.g. decellularization, repopulation and transplantation), extraction and critical appraisal of data and results concerning the conditions for decellularization, repopulation and transplantation.

RESULTS

Decellularization was successfully performed in small and large animal models. Hepatocytes as well as stem cells and hepatic cell lines were applied for repopulation and 7 publications could show the successful transplantation of acellular and repopulated organ scaffolds. The current scientific need for further studies concerning the source of donor organs, optimization of the decellularization process, the cell type for the reseeding process and the establishment of the optimal conditions for the repopulation of the scaffold is still tremendous. For successful recellularization of the liver three goals need to be achieved: (1) reseeding of the organ scaffold with a sufficient amount of parenchymal cells, (2) endothelialization of the vascular tree to ensure the supply of oxygen and nutrients to parenchymal cells and (3) an appropriate epithelialization of the biliary tree. In order to progress to clinical trials a suitable transplantation model to verify the function of the organ constructs must be established.

CONCLUSION

Liver engineering using biological cell-free organ scaffolds represents a scientific and ethical challenge. The existing results emphasize the potential of this new and promising strategy to create organs for transplantation in the future.

Modulation of hepatic perfusion did not improve recovery from hepatic outflow obstruction

Background

Focal hepatic venous outflow obstruction frequently occurs after extended liver resection and leads to a portal hypertension, arterial hypoperfusion and parenchymal necrosis.

In this study, we investigated the pharmacological modulation of liver perfusion and hepatic damage in a surgical model of hepatic outflow obstruction after extended liver resection by administration of 5 different drugs in comparison to an operative intervention, splenectomy.

Methods

Male inbred Lewis rats (Lew/Crl) were subjected to right median hepatic vein ligation + 70% partial hepatectomy. Treatment consisted of a splenectomy or the application of saline, carvedilol or isosorbide-5-mononitrate (ISMN) (5 mg · kg⁻¹ respectively 7,2 mg · kg⁻¹ per gavage 12 h⁻¹). The splenectomy was performed during operation. The effect of the treatments on hepatic hemodynamics were measured in non-operated animals, immediately after operation (n = 4/group) and 24 h after operation (n = 5/group). Assessment of hepatic damage (liver enzymes, histology) and liver cell proliferation (BrdU-immunohistochemistry) was performed 24 h after operation. Furthermore sildenafil (10 μg · kg⁻¹ i.p. 12h⁻¹), terlipressin (0.05 mg · kg⁻¹ i.v. 12 h⁻¹) and octreotide (10 μg · kg⁻¹ s.c. 12 h⁻¹) were investigated regarding their effect on hepatic hemodynamics and hepatic damage 24 h after operation (n = 4/group).

Results

Carvedilol and ISMN significantly decreased the portal pressure in normal non-operated rats from 11,1 ± 1,1 mmHg (normal rats) to 8,4 ± 0,3 mmHg (carvedilol) respectively 7,4 ± 1,8 mmHg (ISMN). ISMN substantially reduced surgery-induced portal hypertension from 15,4 ± 4,4 mmHg to 9,6 ± 2,3 mmHg. Only splenectomy reduced the portal flow immediately after operation by approximately 25%. No treatment had an immediate effect on the hepatic arterial perfusion. In all treatment groups, portal flow increased by approximately 3-fold within 24 h after operation, whereas hepatic arterial flow decreased substantially. Neither treatment reduced hepatic damage as assessed 24 h after operation. The distribution of proliferating cells appeared very similar in all drug treated groups and the splenectomy group.

Conclusion

Transient relative reduction of portal pressure did not result in a reduction of hepatic damage. This might be explained by the development of portal hyperperfusion which was accompanied by arterial hypoperfusion.

Electronic supplementary material

The online version of this article (doi:10.1186/s40360-017-0155-4) contains supplementary material, which is available to authorized users.

[Application of the Objective Structured Clinical Examination (OSCE) in German Medical Schools: An Inventory]

INTRODUCTION

The German medical licensing regulations, as amended by the government in 2002, now require the assessment of clinical skills in undergraduate medical education. As a result, the Objective Structured Clinical Examination (OSCE) was introduced as an assessment tool in many medical schools. This article provides a detailed inventory of the current application of the OSCE assessment in Germany.

METHODS

From June to September 2015, the implementation of the OSCE in all 36 German medical schools was investigated using semi-structured telephone interviews and email correspondence. The areas of focus comprised implementation of the OSCE, and number and type of performance records according to the medical licensing regulations or involved disciplines. Following collection, data were analysed quantitatively and qualitatively.

RESULTS

All medical schools (100%) participated in the survey. Nearly every school (94%) has introduced the OSCE into its assessment portfolio, however, to varying extents. For each location, the numbers range between 0 and 18 (M=4.7) performance records of the clinical science section assessed by OSCEs. The implementation of this assessment format includes most of the clinical performance records, but more than half (51.4%) of these cover surgery, internal medicine, emergency medicine, anaesthesiology, and orthopaedics.

CONCLUSION

The results reported in this paper confirm the widespread introduction of the OSCE assessment in German medical schools. However, the implementation remains heterogeneous with respect to the scope, schools and individual disciplines involved in the process. In order to ensure extensive clinical competence of prospective physicians the application of the OSCE should be broadened. For this purpose, further information to convince medical school staff is still required.

Step Coalescence by Collective Motion at an Incommensurate Grain Boundary

Using extended time series scanning transmission electron microscopy, we investigate structural fluctuations at an incommensurate grain boundary in Au. Atomic-resolution imaging reveals the coalescence of two interfacial steps, or disconnections, of different height via coordinated motion of atoms along close-packed directions. Numerical simulations uncover a transition pathway that involves constriction and expansion of a characteristic stacking fault often associated with grain boundaries in face-centered cubic materials. It is found that local atomic fluctuations by enhanced point defect diffusion may play a critical role in initiating this transition. Our results offer new insights into the collective motion of atoms underlying the lateral advance of steps that control the migration of faceted grain boundaries.

Analysis of grain boundary dynamics using event detection and cumulative averaging

To analyze extended time series of high resolution images, we have employed automated frame-by-frame comparisons that are able to detect dynamic changes in the structure of a grain boundary in Au. Using cumulative averaging of images between events allowed high resolution measurements of the atomic relaxation in the interface with sufficient accuracy for comparison with atomistic models. Cumulative averaging was also used to observe the structural rearrangement of atomic columns at a moving step in the grain boundary. The technique of analyzing changing features in high resolution images by averaging between incidents can be used to deconvolute stochastic events that occur at random intervals and on time scales well beyond that accessible to single-shot imaging.

[Video-based self-control in surgical teaching. A new tool in a new concept]

BACKGROUND

Image and video-based results and process control are essential tools of a new teaching concept for conveying surgical skills. The new teaching concept integrates approved teaching principles and new media.

METHOD

Every performance of exercises is videotaped and the result photographically recorded. The quality of the process and result becomes accessible for an analysis by the teacher and the student/learner. The learner is instructed to perform a criteria-based self-analysis of the video and image material by themselves.

RESULTS

The new learning concept has so far been successfully applied in seven rounds within the newly designed modular class "Intensivkurs Chirurgische Techniken" (Intensive training of surgical techniques). Result documentation and analysis via digital picture was completed by almost every student. The quality of the results was high. Interestingly the result quality did not correlate with the time needed for the exercise. The training success had a lasting effect.

CONCLUSION

The new and elaborate concept improves the quality of teaching. In the long run resources for patient care should be saved when training students according to this concept prior to performing tasks in the operating theater. These resources should be allocated for further refining innovative teaching concepts.

A theoretical study of lipid accumulation in the liver-implications for nonalcoholic fatty liver disease

A hallmark of the nonalcoholic fatty liver disease is the accumulation of lipids. We developed a mathematical model of the hepatic lipid dynamics to simulate the fate of fatty acids in hepatocytes. Our model involves fatty acid uptake, lipid oxidation, and lipid export. It takes into account that storage of triacylglycerol within hepatocytes leads to cell enlargement reducing the sinusoids radius and impairing hepatic microcirculation. Thus oxygen supply is reduced, which impairs lipid oxidation. The analysis of our model revealed a bistable behavior (two stable steady states) of the system, in agreement with histological observations showing distinct areas of lipid accumulation in lobules. The first (healthy) state is characterized by intact lipid oxidation and a low amount of stored lipids. The second state in our model may correspond to the steatotic cell; it is marked by a high amount of stored lipids and a reduced lipid oxidation caused by impaired oxygen supply. Our model stresses the role of insufficient oxygen supply for the development of steatosis. We discuss implications of our results in regard to the experimental design aimed at exploring lipid metabolism reactions under steatotic conditions. Moreover, the model helps to understand the reversibility of lipid accumulation and predicts the reversible switch to show hysteresis. The system can switch from the steatotic state back to the healthy state by reduction of fatty acid uptake below the threshold at which steatosis started. The reversibility corresponds to the observation that caloric restriction can reduce the lipid content in the liver.

Dual role of chloroquine in liver ischemia reperfusion injury: reduction of liver damage in early phase, but aggravation in late phase

The anti-malaria drug chloroquine is well known as autophagy inhibitor. Chloroquine has also been used as anti-inflammatory drugs to treat inflammatory diseases. We hypothesized that chloroquine could have a dual effect in liver ischemia/reperfusion (I/R) injury: chloroquine on the one hand could protect the liver against I/R injury via inhibition of inflammatory response, but on the other hand could aggravate liver I/R injury through inhibition of autophagy. Rats (n=6 per group) were pre-treated with chloroquine (60 mg/kg, i.p.) 1 h before warm ischemia, and they were continuously subjected to a daily chloroquine injection for up to 2 days. Rats were killed 0.5, 6, 24 and 48 h after reperfusion. At the early phase (i.e., 0–6 h after reperfusion), chloroquine treatment ameliorated liver I/R injury, as indicated by lower serum aminotransferase levels, lower hepatic inflammatory cytokines and fewer histopathologic changes. In contrast, chloroquine worsened liver injury at the late phase of reperfusion (i.e., 24–48 h after reperfusion). The mechanism of protective action of chloroquine appeared to involve its ability to modulate mitogen-activated protein kinase activation, reduce high-mobility group box 1 release and inflammatory cytokines production, whereas chloroquine worsened liver injury via inhibition of autophagy and induction of hepatic apoptosis at the late phase. In conclusion, chloroquine prevents ischemic liver damage at the early phase, but aggravates liver damage at the late phase in liver I/R injury. This dual role of chloroquine should be considered when using chloroquine as an inhibitor of inflammation or autophagy in I/R injury.

How similar are inbred rats? The influence of anatomical variations, shipment and sampling time on experimental surgery

Variations among inbred rats in terms of anatomy and routine laboratory values can potentially blur surgical experimental results. Therefore, a retrospective analysis aiming at investigating hepatic and perihepatic anatomical variations, liver weight, body weight, liver weight/body weight ratio (LBWR), variations in routine laboratory values, and the influence of shipment and repeated sampling was performed. In our study, liver weight of rats seemed to be strain-specific. LBWR was weakly and negatively correlated with body weight in rats. A statistically significant difference in routine blood tests was found among normal rats grouped by different body weight or shipment. Weekly repeated sampling from the same rats revealed a statistically significant difference in a blood test. In conclusion, the fact that variation among rats or their environment can blur the results of a surgical experimental study should be kept in mind.

Hepatic arterial perfusion is essential for the spontaneous recovery from focal hepatic venous outflow obstruction in rats

We previously observed that focal hepatic venous outflow obstruction recovered spontaneously by the formation of sinusoidal canals in a rat model of portal hyperperfusion. We aimed to investigate whether the lack of hepatic arterial perfusion aggravates parenchymal damage, decelerates recovery and influences the formation of sinusoidal canals after focal hepatic venous outflow obstruction. Rats were subjected to arterialized versus nonarterialized syngeneic liver transplantation after ligating the right median hepatic vein in the donor. Hepatic damage, microcirculation, regeneration and vascular remodeling were evaluated. In arterialized-recipients, confluent necrosis interspersed with viable periportal islands of hepatocytes, and vascularized sinusoidal canals with visible blood flow, surrounded by normal sinusoidal structure, were visible on postoperative day (POD) 2. Complete parenchymal recovery was consequently established by resorption of necrosis and hepatocyte proliferation, detected in viable portal islands and border zone. Lack of hepatic arterial perfusion caused complete necrosis in the obstruction zone without viable hepatocytes in the periportal area on POD2. Hepatocyte proliferation was only visible in the border zone. On POD28, perfused vascular structures, without neighboring normal sinusoidal structures, were observed in the scar-like area. Hepatic arterial perfusion determined the extent of hepatic necrosis, the formation of vascularized sinusoidal canals and the parenchymal recovery, after focal hepatic venous outflow obstruction.

Highly monodisperse core-shell particles created by solid-state reactions

The size distribution of particles, which is essential for many properties of nanomaterials, is equally important for the mechanical behaviour of the class of alloys whose strength derives from a dispersion of nanoscale precipitates. However, particle size distributions formed by solid-state precipitation are generally not well controlled. Here we demonstrate, through the example of core-shell precipitates in Al-Sc-Li alloys, an approach to forming highly monodisperse particle size distributions by simple solid-state reactions. The approach involves the use of a two-step heat treatment, whereby the core formed at high temperature provides a template for growth of the shell at lower temperature. If the core is allowed to grow to a sufficient size, the shell develops in a 'size focusing' regime, where smaller particles grow faster than larger ones. These results suggest strategies for manipulating precipitate size distributions in similar systems through simple variations in thermal treatments.

A novel end-to-side anastomosis technique for hepatic rearterialization in rat orthotopic liver transplantation to accommodate size mismatches between vessels

BACKGROUND/AIMS

We present our modification of a sutured arterial anastomosis in orthotopic rat liver transplantation as well as a literature survey and analysis of the existing techniques of rearterialization with regard to technical difficulties and potential limitations.

METHODS

The donor common hepatic artery (CHA) was anastomosed to the enlarged lumen of the recipient proper hepatic artery (PHA), tailored to match the size of the donor CHA, with an end-to-side interrupted suture technique. Vascular patency of hepatic rearterialization was assessed both intraoperatively and at the time the liver grafts were harvested (postoperative days 2 and 28). The effect of arterialization on hepatic morphology was confirmed by histological examination and compared to nonarterialized rat orthotopic liver transplantation.

RESULTS

The CHAs had a significantly larger diameter (up to 3-fold) compared to the PHAs, which represents a considerable size mismatch. The anastomosis procedure including the size adaptation required 15-25 min. All anastomoses were patent immediately, 5 min after rearterialization and at both harvest time points. The liver lobular architecture was intact in the rearterialized group, whereas a moderate degree of bile duct proliferation and portal/lobular lymphocytic infiltration were observed in the nonarterialized group.

CONCLUSION

The new technique is a time-consuming and microsurgically challenging but universally applicable and robust procedure accommodating even a substantial mismatch in vessel diameter.

X-Ray Diffraction Analysis and Modeling of Strain Induced Thermal Cycling in a Thin Aluminum (011) Bicrystal Film

Heteroepitaxial films of aluminum bicrystals grown on silicon provide a model system in which to study plasticity in polycrystalline metal thin films. For the bicrystal films, dislocations are confined to move on two different slip plane orientations because of the orientation of the crystals on the substrate. In-situ transmission electron microscopy (TEM) observations during thermal cycling have shown two threshold temperatures for dislocation motion on cooling. A simple model uses the resolved shear stress on the possible slip planes to explain the TEM observations. Mechanisms responsible for the dislocation behavior are studied in-situ during thermal cycling between room temperature and 450°C with x-ray diffraction. The strains are determined using a sin2(Ψ) analysis at each temperature. Direct comparisons are made between the TEM observations, the model and x-ray diffraction results.

Grain Boundary Structure and Morphology in 30° <100> Tricrystal Films of Al

The structure and morphology of 30° <100> tilt grain boundaries in tricrystal films of Al have been investigated by conventional and high resolution electron microscopy. By inducing heteroepitaxial growth on single crystal (111) Si substrates, Al formed polycrystalline thin films made of grains in three symmetry-related (100) orientations. The grain boundaries were well-faceted and a number of symmetric and asymmetric tilt boundaries and triple junctions were observed. Their morphology, topology and preferred faceting was related to the 12mm two-dimensional point symmetry of the tricrystal.

Real Time Observations of Dislocation-Mediated Plasticity in the Epitaxial AI (011)/Si(100) Thin Film System

Despite numerous theoretical and experimental studies of strain relaxation in metal films on silicon substrates, the exact mechanisms by which dislocations mediate plasticity in these structures are not well understood. To elucidate these mechanisms, we present results from in-situ transmission electron microscopy annealing of thin aluminum films grown on Si (100). As a model system, we have chosen to focus on aluminum films which contain two (011) epitaxial variants with respect to the silicon substrate. In this paper we discuss our observations of the glide and climb behavior of dislocations in these structures during thermal cycling. These observations give qualitative insight into the mechanisms by which dislocation motion accommodates thermally induced strains in thin metal films.

PVD Growth of FCC Metal Films On Single Crystal Si And Ge Substrates

Epitaxial films of the fcc metals Al, Au, Ag and Ni were grown by physical vapor deposition on Si and Ge (111), (110) and (100) substrates at different deposition temperatures. The epitaxial relationships and morphological features of these films were characterized by transmission electron microscopy and diffraction in plan view and cross section. Ag formed single crystal films on all substrates at all temperatures. Au and Al could be grown as bicrystals, and under some conditions, Al and Ni grew as tricrystal films. The morphological effects of diffusion at the metal/substrate interface are ascribed to diffusion induced grain boundary migration.

Quantitative HRTEM investigation of an obtuse angle dislocation reaction in gold with a CScorrected field emission microscope

We investigate quantitatively the non periodic arrangement of atom columns surrounding an obtuse angle dislocation reaction in gold utilizing a CM200 FEG instrument equipped with a spherical aberration corrector. The in-plane component of the Burgers vector of the observed stair-rod dislocation is ⅙ [110]. Column positions are determined from single lattice images and compared with those from a reconstructed electron exit wave. We find that absolute position measurements of 1–3 pm require knowledge of the defocus to better than 1 nm which can be achieved by a reconstruction of the exit-plane wave. In contrast, a defocus value of 8.9 nm already leads to apparent displacements as large as 35 pm if single lattice images are considered. Such discrepancies are either caused by residual lens aberrations or by the superposition of delocalization effects at interfaces caused by defocusing of the objective lens. Commonly, however, only relative displacements are of interest. In this case the CS corrector improves the interpretability of single defocused lattice images with a remarkable signal to noise ratio which is advantageous for in-situ experiments. As an example for analyzing in-situ experiments we determine displacements recorded in a time resolved experiment of radiation induced atom motion on surfaces.

Detection of single atoms and buried defects in three dimensions by aberration-corrected electron microscope with 0.5-A information limit

The ability of electron microscopes to analyze all the atoms in individual nanostructures is limited by lens aberrations. However, recent advances in aberration-correcting electron optics have led to greatly enhanced instrument performance and new techniques of electron microscopy. The development of an ultrastable electron microscope with aberration-correcting optics and a monochromated high-brightness source has significantly improved instrument resolution and contrast. In the present work, we report information transfer beyond 50 pm and show images of single gold atoms with a signal-to-noise ratio as large as 10. The instrument's new capabilities were exploited to detect a buried Sigma3 {112} grain boundary and observe the dynamic arrangements of single atoms and atom pairs with sub-angstrom resolution. These results mark an important step toward meeting the challenge of determining the three-dimensional atomic-scale structure of nanomaterials.

Tailoring the microstructure and surface morphology of metal thin films for nano-electro-mechanical systems applications

Metallic structural components for micro-electro-mechanical/nano-electro-mechanical systems (MEMS/NEMS) are promising alternatives to silicon-based materials since they are electrically conductive, optically reflective and ductile. Polycrystalline mono-metallic films typically exhibit low strength and hardness, high surface roughness, and significant residual stress, making them unusable for NEMS. In this study we demonstrate how to overcome these limitations by co-sputtering Ni-Mo. Detailed investigation of the Ni-Mo system using transmission electron microscopy and high-resolution transmission electron microscopy (TEM/HRTEM), x-ray diffraction (XRD), nanoindentation, and atomic force microscopy (AFM) reveals the presence of an amorphous-nanocrystalline microstructure which exhibits enhanced hardness, metallic conductivity, and sub-nanometer root mean square (RMS) roughness. Uncurled NEMS cantilevers with MHz resonant frequencies and quality factors ranging from 200-900 are fabricated from amorphous Ni-Mo. Using a sub-regular solution model it is shown that the electrical conductivity of Ni-Mo is in excellent agreement with Bhatia's structural model of electrical resistivity in binary alloys. Using a Langevin-type stochastic rate equation the structural evolution of amorphous Ni-Mo is modeled; it is shown that the growth instability due to the competing processes of surface diffusion and self-shadowing is heavily damped out due to the high thermal energies of sputtering, resulting in extremely smooth films.

Regulation of hepatic microcirculation in stepwise liver resection

BACKGROUND

After liver resection a small-for-size syndrome may result from the reduction of liver volume and additional liver damage caused by hepatic hyperperfusion. Therefore the influence of the extent of liver resection on liver perfusion is investigated.

MATERIAL AND METHODS

A stepwise liver resection (removal of 30%, 70%, 90%, 95% and 97% of the liver) was performed under inhalation anaesthesia with isoflurane in 6 male Lewis rats. Besides systemic arterial and venous blood pressure the portal pressure and flow was measured and the sinusoidal perfusion was visualized. Sinusoidal diameter, intersinusoidal diameter and functional capillary density were determined.

RESULTS AND CONCLUSIONS

A decrease in the portal flow but an increase in the portal pressure was observed. Sinusoidal diameter showed a steady but low increase when up to 70% of the liver was removed but a high increase after 90% or more of the liver was resected. This indicates a decompensation of a regulatory mechanism of sinusoidal perfusion.

Cellular and humoral immune response to a third generation hepatitis B vaccine

Liver transplantation is often the ultimate option of therapy for chronically hepatitis B virus (HBV) infected patients. Adoptive transfer of HBV immunity with the liver after vaccination of living liver donors (LLD) could be a new approach to prevent reinfection in the recipients. The time to achieve HBV immunity in LLD is usually short (1-2 months). Therefore, we established a short time immunization protocol (four injections in 2 weeks intervals) using Hepimmune, a recombinant vaccine that contains the L, M and S proteins of HBV. We examined cellular and humoral immune responses after immunization with Hepimmune and compared its immunogenicity to that of a standard HBV vaccine containing only the S protein (HBVAXPRO). Cellular immunity was measured by interferon (IFN)-gamma ELISpot and proliferation assay. HBV-specific T cells were detectable in the Hepimmune group after the second and in the standard group after the third vaccination. IFN-gamma production of T cells was significantly higher (P < 0.001) after the third vaccination with Hepimmune. Proliferative responses were also significantly (P < 0.01) higher in the Hepimmune group after the second to fourth vaccination. The humoral immune response could already be detected after the first immunization in nine of 15 Hepimmune vaccinated test persons while it was only observed in one of 15 probands of the later group. Titres differed significantly (P < 0.01) following all four vaccinations. Thus, Hepimmune appears to be a good candidate for short time immunization protocols.

Pb nanoprecipitates in Al: magic-shape effects due to elastic strain

We present a theory for size-dependent shapes of Pb nanoprecipitates in Al, introducing the concept of "magic shapes," i.e., shapes having near-zero homogeneous elastic strains. Our quantitative atomistic calculations of edge energies show their effect on precipitate shape to be negligible, thus it appears that shapes must be due to the combined effect of strain and interface energies. By employing an algorithm for generating magic shapes, we replicate the experimental observations by selecting magic-shape precipitates with interfacial energies less than a cutoff value.

Self-assembled nanofold network formation on layered crystal surfaces during metal intercalation

We study the formation of planar network nanostructures, which develop during metal deposition on initially smooth surfaces of layered compounds. Using in situ low-energy electron microscopy for dynamic observation and high-resolution transmission electron microscopy for structure analysis, we have observed the rapid formation of hexagonal networks of linear "nanofolds" with prismatic cavities on top of layered VSe2 crystals. Their formation results from relaxation of compressive strains which build up during Cu intercalation into a thin surface layer.

The "territorial belonging" of the middle hepatic vein: a troublesome dilemma in adult live donor liver transplantation--anatomical evidence based on virtual 3-dimensional-computed tomography-imaging reconstructions

BACKGROUND

The venous drainage of the liver plays an essential role in securing viability of both graft and remnant in live donor liver transplantation (LDLT). There is still controversy on whether the middle hepatic vein (MHV) should be routinely included as part of the graft or retained with the remnant liver. The purpose of this study was to analyze hepatic venous drainage patterns based on information obtained by 3-dimensional CT-imaging reconstructions.

METHODOLOGY

Fifty five potential live liver donors were evaluated between January 2003 and May 2004 at our Institution. We analyzed two anatomical definitions of liver dominance: total liver dominance (TLD) and hemiliver dominance (HLD). The following concepts were addressed: 1) Hepatic vein territories, 2) Hepatic vein dominance relationship, 3) Territorial belonging- patterns of the MHV to the right and left hemilivers, additionally an analysis of venous outflow in the central liver sectors was performed.

RESULTS

Our results showed that: 1) The definitions of dominance: TLD vs. HLD overlap, displaying the MHV belonging, by taking into account the individual right hepatic vein (RHV) variability; 2) A dominant RHV for the whole liver indicates that the RHV is also dominant in the right hemiliver; 3) The MHV belongs predominantly to the left hemiliver (LHL); 4) The left hepatic vein (LHV) is dominant in the LHL.

CONCLUSION

Both dominance definitions provide independent mappings of the liver and offer helpful insight into venous dominance relationship.

Fluctuation of the cytokine expression in the liver during the chronic woodchuck hepatitis virus (WHV) infection is not related to viral load

The woodchuck together with the woodchuck hepatitis virus (WHV) is an excellent model to study the pathogenesis of hepadnaviral infections. Chronic WHV infection causes severe liver disease and hepatocellular carcinoma in woodchucks. The mechanism of viral clearance is not fully understood, interferons seem to play a major role in down-regulating viral replication prior to elimination of infected hepatocytes. We investigated on the pattern of cytokine and T-cell-marker expression in livers of woodchucks chronically infected with WHV. RNase-protection-assay (RPA) was used to determine mRNA of woodchuck specific genes (TNF-alpha, IFN-gamma, IL-15, CD3, CD4, CD8). Serial liver biopsies were performed daily or weekly in eight chronic WHV-carrier woodchucks. Cytokine/T-cell-marker expression differed significantly between the time points up to +/-50% within each woodchuck. The different expression patterns of cytokines or T-cell-markers did not correlate to the (weak) fluctuations in the viremia but may explain the observed fluctuations in the WHV/HBV-load in chronically infected individuals. Furthermore, we observed associations between cytokine and T-cell-marker expression. The marginal fluctuations in viremia during the chronic infection may indicate, that, once the chronic hepadnaviral infection is established, cytokines/interferons expressed endogenously (i.e. not vector-borne or injected) play only a minor role.

Media remodeling – the result of stent induced media necrosis and repair

Background: Stents have been introduced clinically to help maintaining the patency of the vascular lumen after balloon angioplasty. To ensure a sufficient lumen of the stented vessel, oversized stents are frequently used. However especially deployment of oversized stents may lead to mechanical injury of the intima and media of the vessel wall. The aim of the study was to characterize the vascular lesions and repair processes within the first 4 weeks after implantation of oversized stents in the rabbit carotid artery and thereby contribute to the understanding of vascular remodeling during stent implantation. Methods: Oversized stents were implanted in the carotid artery of Chinchilla rabbits. Rabbits were sacrificed 3, 7, 14, and 28 days after stent implantation and a detailed histologic and immunohistochemical analysis was performed. Results: The carotid artery was expanded by a factor of 1.3–1.5, leading to a constant dilatation of the vessel. The struts were deeply impressed in the vessel wall, resulting in a disruption of the intima, thrombus formation, media compression and segmental media necrosis. The necrotic media was repopulated by smooth muscle cells by day 7. In contrast to the intima lesions, necrotic areas of the media were not invaded by an inflammatory infiltrate. Formation of neointima, characterized by a confluent layer of endothelial cells and deposition collagen fibers started in close vicinity of the struts. Conclusions: Being part of a high-pressure system, the arterial vessel apparently adapts to constant dilatation. Deployment of oversized stents caused intima disruption, media necrosis of varying degree and constant dilatation of the vessel wall. Necrosis and repopulation of smooth muscle cells of the media took place within the first 4 weeks, leading to the speculation whether the repopulating SMC are more resistant to the constant pressure.

Carbon nanotubes as nanoscale mass conveyors

The development of manipulation tools that are not too 'fat' or too 'sticky' for atomic scale assembly is an important challenge facing nanotechnology. Impressive nanofabrication capabilities have been demonstrated with scanning probe manipulation of atoms and molecules on clean surfaces. However, as fabrication tools, both scanning tunnelling and atomic force microscopes suffer from a loading deficiency: although they can manipulate atoms already present, they cannot efficiently deliver atoms to the work area. Carbon nanotubes, with their hollow cores and large aspect ratios, have been suggested as possible conduits for nanoscale amounts of material. Already much effort has been devoted to the filling of nanotubes and the application of such techniques. Furthermore, carbon nanotubes have been used as probes in scanning probe microscopy. If the atomic placement and manipulation capability already demonstrated by scanning probe microscopy could be combined with a nanotube delivery system, a formidable nanoassembly tool would result. Here we report the achievement of controllable, reversible atomic scale mass transport along carbon nanotubes, using indium metal as the prototype transport species. This transport process has similarities to conventional electromigration, a phenomenon of critical importance to the semiconductor industry.

Adoptive transfer of donor-derived immunity by liver transplantation: a potential avenue to prevent hepatitis B virus reinfection

Immunity to hepatitis B has been successfully transferred by bone marrow transplantation, but has also occurred after liver transplantation (LTx). This study was designed to analyse the influence of alloreactivity and immunosuppression, on the efficacy of adoptive immune transfer to hepatitis B by liver transplantation. Orthotopic LTx (n = 34) were performed in three rat strain combinations representing different genetic constellations. Donors had been vaccinated twice with recombinant hepatitis B surface antigen while recipients were unimmunized. Half of the allogeneic recipients were immunosuppressed with cyclosporin A. All animals were monitored weekly for the presence of anti-hepatitis B surface antibodies (anti-HBs). Effective anti-HBs titres were detected in 85% (29/34) of liver recipients and lasted from 2 to 10 weeks. Donor titre above >15 000 mIU/mL ensured a 100% seroconversion rate in the recipients. The maximal anti-HBs titre in recipients represented 0.06% approximately 0.76% of the donor titre. Rejection reduced the adoptive immune transfer, which was protected by immunosuppression. These observations suggest that transfer of functionally active donor lymphocytes, deriving from the graft, contributed to the donor-derived immune response in the recipient. Further studies to augment the donor-derived immune response are warranted to ensure a therapeutic effect for the recipient at risk of reinfection.

Chevron defect at the intersection of grain boundaries with free surfaces in Au

We have identified a new defect at the intersection between grain boundaries and surfaces in Au using atomic resolution transmission electron microscopy. At the junction line of 90 degrees <110> tilt grain boundaries of (110)-(001) orientation with the free surface, a small segment of the grain boundary, about 1 nm in length, dissociates into a triangular region with a chevronlike stacking disorder and a distorted hcp structure. The structure and stability of these defects are confirmed by atomistic simulations, and we point out the relationship with the one-dimensional incommensurate structure of the grain boundary.

Electron microscopy observations on the role of twinning in the evolution of microstructures

Twinning plays an important role in phase transformations and can have significant effects on microstructural evolution. Different roles of twinning in the development of microstructures during precipitation and phase transformations are reviewed and illustrated with examples from investigations by high-resolution electron microscopy, including the effect of multiple twinning on the development of Ge precipitates in Al-Ge and Ag-Ge alloys, the twin dissociation of grain boundaries in Au, the formation of hexagonal Si at twin intersections and the effect of twin boundaries on the equilibrium shape of Pb inclusions in Al.

Prolonged suppression of humoral immune response after organ transplantation

Rats receiving either kidney or liver grafts were vaccinated with recombinant hepatitis B virus (HBV) vaccine either 1 or 10 weeks post-transplantation to explore the nonspecific immunosuppressive effect of transplantation surgery on antibody development. Response rate and geometric mean titer of the anti-HBs antibody were significantly lower in organ-transplanted animals undergoing early vaccination compared to unoperated control animals. Both parameters were affected when vaccination was performed early after kidney transplantation, but also in case of late vaccination in liver graft recipients. The nonspecific suppressive effect of transplantation surgery on the humoral immune response was related to the time point of vaccination after surgery and the extent of the surgical intervention and lasted longer than previously reported.

[Pancreatico-bronchial fistula with communication to a pseudoaneurysm of the arteria lienalis as a rare complication in chronic pancreatitis]

Thoracic manifestations of internal pancreatic fistulas caused by chronic pancreatitis are rare conditions. The three main types of these manifestations are mediastinal pseudocysts, pancreatico pleural fistulas and pancreaticobronchial fistulas. We report on one patient with the clinical presentation of all three thoracic internal pancreatic fistulas with a communication to a pseudoaneurysm of the splenic artery caused by chronic alcohol-related pancreatitis. Conservative therapy over four weeks was not successful. Resection of the pseudoaneurysm, debridement of the mediastinal pseudocyst and duodenum preserving resection of the pancreas treated all complications and prevents recurrence in this patient with chronic pancreatitis.

An in situ nanoindentation specimen holder for a high voltage transmission electron microscope

We describe in detail, the design, construction, and testing of a specimen holder that allows for the nanoindentation of surfaces while viewing in cross-section in a high voltage transmission electron microscope (TEM). This nanoindentation specimen holder, having three-axis position control of a diamond indenter in combination with micromachined specimens, allows for the first time the dynamic observation of subsurface microstructure evolution under an indenter tip. Additionally, the sample design techniques that have been developed for these procedures may eliminate the need for TEM specimen preparation for additional ex situ nanoindentation experiments. Initial experimental results from in situ indentation of Si samples in the high voltage electron microscope are reported here to demonstrate the capability of this new specimen holder.