[Fractures of the lateral condyle of the humerus in children : High risk of secondary dislocation with conservative treatment]

BACKGROUND

Fractures of the lateral condyle of the humerus in children are articular fractures with difficult diagnostics due to the incompletely ossified elbow joint. The aim of this study was to evaluate the method of treatment at initial presentation and to analyze the frequency of subsequent displacement during follow-up.

MATERIAL AND METHOD

Retrospective analysis of the frequency of primary fracture dislocation and subsequent displacement of fractures of the lateral condyle of the humerus in children under 16 years of age between 2004 and 2021. Conventional radiographs in two planes at the time of the accident and in the follow-up after 5-7 days were evaluated.

RESULTS

A total of 285 fractures of the lateral condyle of the humerus were evaluated. The average age was 5.3 years. Of the fractures 109 (38.3%) were directly surgically treated in cases of primary displacement and 176 fractures (61.7%) were not primarily displaced and were initially treated conservatively. During follow-up, subsequent displacement was evident in 46 fractures (26.1%). A total of 130 fractures (45.6%) were treated conservatively and 155 fractures (54.4%) were treated surgically using open joint visualization and screw osteosynthesis or K‑wire osteosynthesis.

CONCLUSION

Fractures of the lateral condyle of the humerus occur more frequently in a certain age group and require targeted radiological diagnostics. Nondisplaced fractures can be treated conservatively but essential radiological follow-up shows a high number of subsequent displacements, so that open surgical stabilization is often necessary.

Revealing the quantum nature of the voltage-induced conductance changes in oxygen engineered yttrium oxide-based RRAM devices

In this work, the quasi-analog to discrete transition occurring in the current-voltage characteristic of oxygen engineered yttrium oxide-based resistive random-access memory (RRAM) devices is investigated in detail. In particular, the focus of our research is not on the absolute conductance values of this characteristic but on the magnitude of its conductance changes occurring during the reset process of the device. It is found that the detected changes correspond to conductance values predominantly of the order of the quantum unit of conductance G0 = 2e2/h, where e is the electron charge and h the Planck constant. This feature is observed even at conductance levels far above G0, i.e. where electron transport is seemingly diffusive. It is also observed that such behavior is reproducible across devices comprising yttrium oxide layers with different oxygen concentrations and measured under different voltage sweep rates. While the oxygen deficiency affects the total number of quantized conductance states, the magnitude of the changes in conductance, close to 1 G0, is invariant to the oxygen content of the functional layer.

Study of the possibility of high accuracy flow measurements with the pulsed neutron activation method

The performance of water flow measurements with pulsed neutron activation (PNA) have been investigated in the past few years. In this report the following particular Problems were investigated: (a) the effect of collimation on the time-resolved detector signals; (b) the behavior of the background signal, in order to expedite optimum background elimination from the measured signals; and (c) the properties of water mixing, by measuring the geometrical asymmetry of the activated volume as a function of distance from the source as well as of flow velocity. It was seen that with the flow velocities and Reynolds numbers in the present experiments, the mixing is not perfect. Thus, in general, the PNA method will lead to an underestimation of the mass flow due to the effect of the laminar layer close to the wall whose contribution to the total mass flow will be enhanced. The investigations reported here contribute to the improvement of the accuracy of the method.

[Elastic, stable intramedullary nailing of pertrochanteric femoral fractures in children (<6-8 years)]

Operationsziel

Minimal-invasive, übungsstabile Versorgung von pertrochantären Femurfrakturen bei Kindern < 6 bis 8 Jahren mittels elastisch-stabiler intramedullärer Nagelung (ESIN).

Indikationen

Proximale, pertrochantäre Femurfrakturen Delbet Typ IV bei Kindern < 6 Jahre.

Kontraindikationen

Trümmerfrakturen, Schenkelhalsfrakturen.

Operationstechnik

Durch Einbringen von insgesamt 3 (gelegentlich nur 2) im proximalen Drittel vorgebogenen, elastischen Titannägeln (TEN) retrograd in das Femur wird im proximalen Fragment eine stabile 3‑Punkt-Abstützung erreicht. Eine weitere Verbesserung der Stabilität kann durch die Applikation von Endcaps erreicht werden.

Weiterbehandlung

Die Nachbehandlung erfolgt mittels Sohlenbelastung während 4 bis 5 Wochen. Röntgenkontrollen erfolgen direkt postoperativ sowie nach 4 bis 5 Wochen. Eine Sportunfähigkeit besteht für 3 Monate.

Ergebnisse

In unserem Patientengut haben wir gute Erfahrungen mit dieser Technik bei den sehr seltenen pertrochantären Frakturen bei Kindern < 6 bis 8 Jahren. Mit minimal-invasivem Vorgehen kann eine übungsstabile Versorgung ohne Notwendigkeit eines Becken-Bein-Gipses erreicht werden.

Investigation of SiO2-Al2O3 nanolaminates for protection of silver reflectors

H₂S and particles from the atmosphere can damage silver reflectors. These defects lead to scattering and a reduction of reflectivity. With regard to these risks, the suitability of sputtered SiO₂, Al₂O₃, and SiO₂-Al₂O₃ nanolaminates for the protection of Ag was analyzed. The optical properties, protection properties against H₂S, solubility, film stress, and protection properties against particle-induced defect formation have been investigated. Especially in the case of particle-induced defects on protected Ag, differences between the protective coatings are considerable, and the nanolaminate layers have advantageous properties.

Investigation of the refractive index repeatability for tantalum pentoxide coatings, prepared by physical vapor film deposition techniques

Random effects in the repeatability of refractive index and absorption edge position of tantalum pentoxide layers prepared by plasma-ion-assisted electron-beam evaporation, ion beam sputtering, and magnetron sputtering are investigated and quantified. Standard deviations in refractive index between 4*10^-4 and 4*10^-3 have been obtained. Here, lowest standard deviations in refractive index close to our detection threshold could be achieved by both ion beam sputtering and plasma-ion-assisted deposition. In relation to the corresponding mean values, the standard deviations in band-edge position and refractive index are of similar order.

Estimation of the composition of coelectron-beam-evaporated thin-mixture films by making use of the Wiener bounds

Material mixtures offer prospective possibilities for synthesizing coating materials with tailored optical constants. We present experimental results for mixture coatings of alumina/aluminum fluoride and alumina/hafnia deposited by electron beam evaporation. Thereby, the volume filling factors of the components are commonly estimated on the basis of deposition rates measured by quartz crystal microbalance. The interplay between the vapor fluxes from the two evaporation sources, the crosstalk between quartz crystal microbalances, and the influence of the plasma source on the tooling factors limit the accuracy of this estimation, and this has motivated us to develop an alternative approach. The general idea of our approach is based on the commonly high accuracy in thin-film optical constant determination using spectrophotometry. Therefore, these optical constants serve as a reliable input for a rather simple but robust evaluation procedure based on the concept of Wiener bounds. The consistency of the obtained results is illustrated by opposing the data to the elementary film composition estimated from energy-dispersive x-ray spectroscopy.

Stellar dynamics. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova

Hypervelocity stars (HVSs) travel with velocities so high that they exceed the escape velocity of the Galaxy. Several acceleration mechanisms have been discussed. Only one HVS (US 708, HVS 2) is a compact helium star. Here we present a spectroscopic and kinematic analysis of US 708. Traveling with a velocity of ~1200 kilometers per second, it is the fastest unbound star in our Galaxy. In reconstructing its trajectory, the Galactic center becomes very unlikely as an origin, which is hardly consistent with the most favored ejection mechanism for the other HVSs. Furthermore, we detected that US 708 is a fast rotator. According to our binary evolution model, it was spun-up by tidal interaction in a close binary and is likely to be the ejected donor remnant of a thermonuclear supernova.

Protected and enhanced aluminum mirrors for the VUV

Aluminum layers protected with fluoride coatings have been deposited by evaporation and characterized with respect to their suitability as vacuum ultraviolet (VUV) mirrors. Optical characterization has been performed by spectrophotometry, while the surface quality of the layers has been judged by means of x ray reflection, scanning electron microscopy, and atomic force microscopy. In particular, protection with aluminum fluoride results in superior VUV reflection properties. VUV reflectance values between 80% and nearly 90% have been verified even two years after deposition and exposure to the atmosphere.

Impact of emotion on cognition in trauma survivors: what is the role of posttraumatic stress disorder?

BACKGROUND

Cognitive theories of anxiety disorders postulate an increased attentional bias to environmental cues associated with threat that underlies the exaggerated fear response. The role of trauma, which may represent strong competitive advantage for attention, remains unclear. We investigated the influence of trauma exposure and the presence of anxiety/stress disorders on the impact of emotional distractors on cognitive performance.

METHODS

Fourteen trauma-exposed subjects with PTSD, 12 trauma-exposed subjects with anxiety disorders other than PTSD, 12 trauma-exposed healthy subjects and 19 non-trauma-exposed healthy controls participated in this study. The impact of emotion on cognition was determined by the Affective Stroop task that measures the effect of irrelevant emotional distractors on the speed of operant responding.

RESULTS

The speed of cognitive performance was significantly reduced in the presence of negative distractors versus neutral or positive distractors in subjects with PTSD, while there was no significant influence of the distractor type on performance in the other diagnostic groups (diagnosis-by-distractor type interaction, p<0.001). While negative distractors induced the same levels of anxiety and depersonalization in subjects with PTSD and subjects with other anxiety disorders, distractor-induced depersonalization was associated with slowing of cognitive performance in PTSD (p=0.02) but not in other groups.

LIMITATIONS

Different types of anxiety disorders in the non-PTSD group might reduce the selectivity of the results; some subjects received medication possibly impacting on their cognitive functioning.

CONCLUSIONS

The cognitive impairments in the presence of negative distractors specifically found in PTSD call for research into novel psychotherapeutic approaches, e.g. attentional training, for PTSD.

Glucose regulation of β-cell stress in type 2 diabetes

In type 2 diabetes, the β-cell is exposed to chronic hyperglycaemia, which increases its metabolic activity, with excess generation of reactive oxygen species (ROS) as a consequence. ROS accumulation induces both oxidative and endoplasmic reticulum (ER) stress, which may lead to β-cell dysfunction and apoptosis. Recent data suggest that oxidative and ER stress are interconnected, although the mechanisms involved in nutrient regulation of the different stress pathways are dissimilar. Several components of the oxidative and ER stress machineries have important roles in the physiological response to glucose and are thus necessary for normal β-cell function. Glucose stimulates signalling pathways that provide crucial messages for β-cell adaptation to metabolic stress; however, the same pathways may eventually lead to apoptosis. Dynamic, temporally fluctuating activation of stress signalling is probably required for the maintenance of β-cell survival, whereas its persistent activation results in β-cell dysfunction and apoptosis. Thus, stress signalling is a 'double-edged sword' that may promote adaptation or apoptosis according to the balance between the divergent outputs of the various pathways. Developing new strategies for β-cell protection based on inhibition of oxidative and/or ER stress requires comprehensive understanding of the switch from β-cell adaptation to β-cell apoptosis under conditions of metabolic stress, such as occurs under hyperglycaemic conditions.

Neuronal nitric oxide synthase protects the pancreatic beta cell from glucolipotoxicity-induced endoplasmic reticulum stress and apoptosis

AIMS/HYPOTHESIS

Cytokines stimulate nitric oxide production in pancreatic beta cells, leading to endoplasmic reticulum (ER) stress and apoptosis. Treatment of beta cells with glucose and NEFA induces nitric oxide synthase (NOS) as well as ER stress. However, the role of NO in glucolipotoxicity-induced ER stress in beta cells is not clear.

METHODS

We studied the effect of high glucose and palmitate levels on NOS isoform production in rat and Psammomys obesus islets and in insulinoma-1E beta cells. The effects of neuronal NOS (nNOS) inhibition by small interfering RNA or by N (omega)-nitro-L-arginine methyl ester (L-NAME) on beta cell function, ER stress and apoptosis under conditions of glucolipotoxicity were investigated.

RESULTS

Overnight incubation of rat and P. obesus islets at 22.2 mmol/l glucose with 0.5 mmol/l palmitate induced the production of nNOS but not inducible NOS (iNOS), in contrast with the robust stimulation of iNOS by cytokines. NOS inhibition by L-NAME did not prevent the decrease in glucose-stimulated insulin secretion and proinsulin biosynthesis or the depletion of islet insulin content observed under conditions of glucolipotoxicity. Moreover, treatment of beta cells with palmitate and L-NAME together resulted in marked activation of the IRE1alpha and PERK pathways of the unfolded protein response. This was associated with increased JNK phosphorylation and apoptosis in islets and beta cells. Moreover, partial nNos knockdown increased JNK phosphorylation and CHOP production, leading to apoptosis.

CONCLUSIONS/INTERPRETATION

In beta cells subjected to glucolipotoxic conditions, chronic inhibition of NOS exacerbates ER stress and activates JNK. Therefore, induction of nNOS is an adaptive response to glucolipotoxicity that protects beta cells from stress and apoptosis.

Balancing needs and means: the dilemma of the beta-cell in the modern world

The insulin resistance of type 2 diabetes mellitus (T2DM), although important for its pathophysiology, is not sufficient to establish the disease unless major deficiency of beta-cell function coexists. This is demonstrated by the fact that near-physiological administration of insulin (CSII) achieved excellent blood glucose control with doses similar to those used in insulin-deficient type 1 diabetics. The normal beta-cell adapts well to the demands of insulin resistance. Also in hyperglycaemic states some degree of adaptation does exist and helps limit the severity of disease. We demonstrate here that the mammalian target of rapamycin (mTOR) system might play an important role in this adaptation, because blocking mTORC1 (complex 1) by rapamycin in the nutritional diabetes model Psammomys obesus caused severe impairment of beta-cell function, increased beta-cell apoptosis and progression of diabetes. On the other hand, under exposure to high glucose and FFA (gluco-lipotoxicity), blocking mTORC1 in vitro reduced endoplasmic reticulum (ER) stress and beta-cell death. Thus, according to the conditions of stress, mTOR may have beneficial or deleterious effects on the beta-cell. beta-Cell function in man can be reduced without T2DM/impaired glucose tolerance (IGT). Prospective studies have shown subjects with reduced insulin response to present, several decades later, an increased incidence of IGT/T2DM. From these and other studies we conclude that T2DM develops on the grounds of beta-cells whose adaptation capacity to increased nutrient intake and/or insulin resistance is in the lower end of the normal variation. Inborn and acquired factors that limit beta-cell function are diabetogenic only in a nutritional/metabolic environment that requires high functional capabilities from the beta-cell.

Insulin counteracts glucotoxic effects by suppressing thioredoxin-interacting protein production in INS-1E beta cells and in Psammomys obesus pancreatic islets

AIMS/HYPOTHESIS

In type 2 diabetes, glucose toxicity leads to beta cell apoptosis with decreased beta cell mass as a consequence. Thioredoxin-interacting protein (TXNIP) is a critical mediator of glucose-induced beta cell apoptosis. Since hyperglycaemia leads to elevated serum insulin, we hypothesised that insulin is involved in the regulation of TXNIP protein levels in beta cells.

METHODS

We studied the production of TXNIP in INS-1E beta cells and in islets of Psammomys obesus, an animal model of type 2 diabetes, in response to glucose and different modulators of insulin secretion.

RESULTS

TXNIP production was markedly augmented in islets from diabetic P. obesus and in beta cells exposed to high glucose concentration. In contrast, adding insulin to the culture medium or stimulating insulin secretion with different secretagogues suppressed TXNIP. Inhibition of glucose and fatty acid-stimulated insulin secretion with diazoxide increased TXNIP production in beta cells. Nitric oxide (NO), a repressor of TXNIP, enhanced insulin signal transduction, whereas inhibition of NO synthase abolished its activation, suggesting that TXNIP inhibition by NO is mediated by stimulation of insulin signalling. Treatment of beta cells chronically exposed to high glucose with insulin reduced beta cell apoptosis. Txnip knockdown mimicking the effect of insulin prevented glucose-induced beta cell apoptosis.

CONCLUSIONS/INTERPRETATION

Insulin is a potent repressor of TXNIP, operating a negative feedback loop that restrains the stimulation of TXNIP by chronic hyperglycaemia. Repression of TXNIP by insulin is probably an important compensatory mechanism protecting beta cells from oxidative damage and apoptosis in type 2 diabetes.

Antireflection of transparent polymers by advanced plasma etching procedures

Self-organized nanostructures that provide antireflection properties grow on PMMA caused by plasma ion etching. A new procedure uses a thin initial layer prior to the etching step. Different types of antireflective structures can now be produced in a shorter time and with fewer limitations on the type of polymer that can be used. The durability of the structured surfaces can be improved by the deposition of additional thin films.

Deposition and spectral performance of an inhomogeneous broadband wide-angular antireflective coating

Gradient index coatings and optical filters are a challenge for fabrication. In a round-robin experiment, basically the same hybrid antireflection coating for the visible spectral region, combining homogeneous refractive index layers of pure materials and linear gradient refractive index layers of material mixtures, has been deposited. The experiment involved three different deposition techniques: electron-beam evaporation, ion-beam sputtering, and radio frequency magnetron sputtering. The material combinations used by these techniques were Nb(2)O(5)/SiO(2), TiO(2)/SiO(2), and Ta(2)O(5)/SiO(2), respectively. The spectral performances of samples coated on one side and on both sides have been compared to the corresponding theoretical spectra of the designed profile. Also, the reproducibility of results for each process is verified. Finally, it is shown that ion-beam sputtering gave the best results in terms of deviation from the theoretical performance and reproducibility.

Mitochondrial regulation of insulin production in rat pancreatic islets

AIMS/HYPOTHESIS

The study was designed to identify the key metabolic signals of glucose-stimulated proinsulin gene transcription and translation, focusing on the mechanism of succinate stimulation of insulin production.

METHODS

Wistar rat islets were incubated in 3.3 mmol/l glucose with and without esters of different mitochondrial metabolites or with 16.7 mmol/l glucose. Proinsulin biosynthesis was analysed by tritiated leucine incorporation into newly synthesised proinsulin. Preproinsulin gene transcription was evaluated following transduction with adenoviral vectors expressing the luciferase reporter gene under the control of the rat I preproinsulin promoter. Steady-state preproinsulin mRNA was determined using relative quantitative PCR. The mitochondrial membrane potential was measured by microspectrofluorimetry using rhodamine-123.

RESULTS

Succinic acid monomethyl ester, but not other mitochondrial metabolites, stimulated preproinsulin gene transcription and translation. Similarly to glucose, succinate increased specific preproinsulin gene transcription and biosynthesis. The inhibitor of succinate dehydrogenase (SDH), 3-nitropropionate, abolished glucose- and succinate-stimulated mitochondrial membrane hyperpolarisation and proinsulin biosynthesis, indicating that stimulation of proinsulin translation depends on SDH activity. Partial inhibition of SDH activity by exposure to fumaric acid monomethyl ester abolished the stimulation of preproinsulin gene transcription, but only partially inhibited the stimulation of proinsulin biosynthesis by glucose and succinate, suggesting that SDH activity is particularly important for the transcriptional response to glucose.

CONCLUSIONS/INTERPRETATION

Succinate is a key metabolic mediator of glucose-stimulated preproinsulin gene transcription and translation. Moreover, succinate stimulation of insulin production depends on its metabolism via SDH. The differential effect of fumarate on preproinsulin gene transcription and translation suggests that these processes have different sensitivities to metabolic signals.

A retrospective study of SSRI treatment in adolescent anorexia nervosa: insufficient evidence for efficacy

Although selective-serotonin-reuptake-inhibitors (SSRI) have been of limited efficacy in the treatment of eating disorder psychopathology and comorbid symptoms of malnourished patients with anorexia nervosa (AN), there is recent data suggesting that SSRI may play a role in preventing relapse among weight-restored patients. Though some previous studies included patients in late adolescence, the vast majority of investigated subjects have been adults. The aim of our retrospective study was to assess the effects of SSRI treatment in partially weight-restored children and adolescents with AN. Thirty two females with AN (mean 14.5+/-1.4 years) were investigated three times during inpatient treatment and at 3- and 6-month follow-up for BMI, eating disorder psychopathology, depressive symptomology, and obsessive-compulsive symptomology. Medication history during inpatient and outpatient treatment was reconstructed at the 6-month follow-up. Nineteen patients received SSRI treatment, while 13 subjects were non-medicated. In comparison to the non-SSRI group, the SSRI group had similar BMI and obsessive-compulsive scores, but higher levels of core eating disorder psychopathology and depressive symptoms at the start of medication. Rates of re-admissions were similar in both groups (SSRI group: 36%, non-SSRI group: 31%, Phi: p=0.72). Repeated measures ANOVA revealed no significant group with time interactions for BMI-SDS (p=0.84), core eating disorder symptoms (ANIS, p=0.79), depression (DIKJ, p=0.75), and obsessive-compulsive (CY-BOCS, p=0.40) scores indicating minimal or no effects of SSRI medication on the course of these variables. In conclusion, our results challenge the efficacy of SSRI medication in the treatment of eating disorder psychopathology as well as depressive and obsessive-compulsive comorbidity in adolescent AN. Clinicians should be chary in prescribing SSRI in adolescent AN unless randomized controlled trials have proofed the benefit of these drugs.

Delayed autoregulation of glucose transport in vascular endothelial cells

AIMS/HYPOTHESIS

We aimed to characterise the development of autoregulation of glucose transport in vascular endothelial cells and its relationship to 12-lipoxygenase (12-LO) expression.

METHODS

Bovine aortic endothelial cells were exposed to 5.5 and 23.0 mmol/l glucose for up to 48 h. The rates of glucose transport, GLUT-1 and 12-LO expression and of 12-hydroxyeicosatetraenoic acid (12-HETE) production were determined.

RESULTS

We showed high glucose-dependent downregulation of glucose transport and transporter in vascular endothelial cells within 36-48 h. A similar time-dependent increase in the expression of 12-LO and the generation of its product 12-HETE was also observed. This downregulatory process was prevented when lipoxygenase activity was inhibited.

CONCLUSIONS/INTERPRETATION

Vascular endothelial cells, which were previously thought to be "glucose-blind", do in fact downregulate GLUT-1 expression and the rate of glucose transport in response to extended exposure to high glucose concentrations. This slow development of glucose-induced downregulation in vascular endothelial cells is related to the slower basal rate of glucose transport in these cells and the slow induction of 12-LO. These data are interesting in view of current hypotheses that attribute vascular endothelial cell dysfunction in diabetes to the lack of a glucose-induced autoregulatory response.

Improvement of metabolic state in an animal model of nutrition-dependent type 2 diabetes following treatment with S 23521, a new glucagon-like peptide 1 (GLP-1) analogue

Glucagon-like peptide 1 (GLP-1) analogues are considered potential drugs for type 2 diabetes. We studied the effect of a novel GLP-1 analogue, S 23521 ([a8-des R36] GLP-1-[7-37]-NH2), on the metabolic state and beta-cell function, proliferation and survival in the Psammomys obesus model of diet-induced type 2 diabetes. Animals with marked hyperglycaemia after 6 days of high-energy diet were given twice-daily s.c. injection of 100 microg/kg S 23521 for 15 days. Food intake was significantly decreased in S 23251-treated P. obesus; however, there was no significant difference in body weight from controls. Progressive worsening of hyperglycaemia was noted in controls, as opposed to maintenance of pre-treatment glucose levels in the S 23521 group. Prevention of diabetes progression was associated with reduced mortality. In addition, the treated group had higher serum insulin, insulinogenic index and leptin, whereas plasma triglyceride and non-esterified fatty acid levels were decreased. S 23521 had pronounced effect on pancreatic insulin, which was 5-fold higher than the markedly depleted insulin reserve of control animals. Immunohistochemical analysis showed islet degranulation with disrupted morphology in untreated animals, whereas islets from S 23521-treated animals appeared intact and filled with insulin; beta-cell apoptosis was approximately 70% reduced, without a change in beta-cell proliferation. S 23521 treatment resulted in a 2-fold increase in relative beta-cell volume. Overall, S 23521 prevented the progression of diabetes in P. obesus with marked improvement of the metabolic profile, including increased pancreatic insulin reserve, beta-cell viability and mass. These effects are probably due to actions of S 23521 both directly on islets and via reduced food intake, and emphasize the feasibility of preventing blood glucose deterioration over time in type 2 diabetes.

5-Fluorouracil in vesicular phospholipid gels for anticancer treatment: entrapment and release properties

Vesicular phospholipid gels (VPG), i.e. highly concentrated liposomal dispersions, are suitable for entrapping substances such as anticancer drugs with particular high encapsulation efficiencies (EE). We prepared different formulations of VPG with 30% (w/w) lipid containing 5-fluorouracil (5-FU) by high pressure homogenization and analysed their EE and drug release. Using mixtures of hydrogenated soy phosphatidylcholine and cholesterol with molar ratios ranging from 55/45 to 75/25, a decreasing amount of cholesterol correlated with an increasing EE, which is probably due to a reduced amount of smaller vesicles and number of lamellae. Using a 5-FU solution of pH 8.6 for VPG preparation, an EE of approximately 40% was found after redispersion of the gel to a liposomal dispersion and separation of free drug from liposomal drug by size exclusion chromatography. The reduced EE for preparations with lower pH values was attributed to a fast initial drug release due to the increased drug lipophilicity below the pK(a) value of 8. After redispersion of a VPG of pH 8.0, an initially faster release of about a third of the entrapped drug was found during the first 20 min, followed by stable entrapment over many hours. The rapid initial release may be due to the portion of liposomes smaller than 40 nm in diameter, determined by photon correlation spectroscopy. Cryo electron microscopic pictures show a lentil-like shape of these small liposomes. The membrane defects on the edges are probably the reason for the very high initial drug release rate. The half-life time of the release of 5-FU from intact FU-VPG at both pH 7.4 and 8.0 was found to be in the order of 4-5 h and the kinetics are typical for matrix-controlled drug diffusion. The in vitro data of 5-FU loaded VPG suggest their applicability as implants with controlled release properties or, after redispersion, as intravenously injected liposomal formulations.

Chiral dynamics of deeply bound pionic atoms

We present and discuss a systematic calculation, based on two-loop chiral perturbation theory, of the pion-nuclear s-wave optical potential. A proper treatment of the explicit energy dependence of the off-shell pion self-energy together with (electromagnetic) gauge invariance of the Klein-Gordon equation turns out to be crucial. Accurate data for the binding energies and widths of the 1s and 2p levels in pionic 205Pb and 207Pb are well reproduced without need for a notorious "missing repulsion" in the pion-nuclear s-wave optical potential. The connection with the in-medium change of the pion decay constant is clarified.

XML-based visualization of design and completeness in medical databases

PURPOSE

mdplot (medical database plot) visualizes both structure and quality of data in medical databases by means of a summary representation of design and completeness in XML format. The goal is to identify attributes suitable for evaluation and to aid in creating open data models.

METHODS

A three-stage visualization approach is applied. First, an overview of all classes in a database, second a detailed view of a specific class and third an analysis of individual attributes. Missing data is identified to enable specific efforts to improve data quality prior to analysis. For each class number of patients, attributes, and records per patient are provided. A condensed bar chart for each category of attributes (categorical, numerical, text and other) visualizes available content: The abscissa corresponds to the sequence of attributes; the ordinate represents completeness per attribute. By selection of a specific class, a detailed description is provided including mean completeness in each category as well as completeness per attribute. To analyse attributes that are collected at several time points per patient, a frequency distribution of records per patient can be generated.

RESULTS

The new methodology was applied to two clinical research databases consisting of 292 attributes (955 patients) and 224 attributes (610 patients), respectively, and resulted in major restructuring of the systems. A public website is provided for generation of mdplots.

IPF1/PDX1 deficiency and beta-cell dysfunction in Psammomys obesus, an animal With type 2 diabetes

The homeodomain transcription factor IPF1/PDX1 is required in beta-cells for efficient expression of insulin, glucose transporter 2, and prohormone convertases 1/3 and 2. Psammomys obesus, a model of diet-responsive type 2 diabetes, shows markedly depleted insulin stores when given a high-energy (HE) diet. Despite hyperglycemia, insulin mRNA levels initially remained unchanged and then decreased gradually to 15% of the basal level by 3 weeks. Moreover, insulin gene expression was not increased when isolated P. obesus islets were exposed to elevated glucose concentrations. Consistent with these observations, no functional Ipf1/Pdx1 gene product was detected in islets of newborn or adult P. obesus using immunostaining, Western blot, DNA binding, and reverse transcriptase-polymerase chain reaction analyses. Other beta-cell transcription factors (e.g., ISL-1, Nkx2.2, and Nkx6.1) were expressed in P. obesus islets, and the DNA binding activity of the insulin transcription factors RIPE3b1-Act and IEF1 was intact. Ipf1/Pdx1 gene transfer to isolated P. obesus islets normalized the defect in glucose-stimulated insulin gene expression and prevented the rapid depletion of insulin content after exposure to high glucose. Taken together, these results suggest that the inability of P. obesus islets to adapt to dietary overload, with depletion of insulin content as a consequence, results from IPF1/PDX1 deficiency. However, because not all animals become hyperglycemic on HE diet, additional factors may be important for the development of diabetes in this animal model.

Glucose induces beta-cell apoptosis via upregulation of the Fas receptor in human islets

In autoimmune type 1 diabetes, Fas-to-Fas-ligand (FasL) interaction may represent one of the essential pro-apoptotic pathways leading to a loss of pancreatic beta-cells. In the advanced stages of type 2 diabetes, a decline in beta-cell mass is also observed, but its mechanism is not known. Human islets normally express FasL but not the Fas receptor. We observed upregulation of Fas in beta-cells of type 2 diabetic patients relative to nondiabetic control subjects. In vitro exposure of islets from nondiabetic organ donors to high glucose levels induced Fas expression, caspase-8 and -3 activation, and beta-cell apoptosis. The effect of glucose was blocked by an antagonistic anti-Fas antibody, indicating that glucose-induced apoptosis is due to interaction between the constitutively expressed FasL and the upregulated Fas. These results support a new role for glucose in regulating Fas expression in human beta-cells. Upregulation of the Fas receptor by elevated glucose levels may contribute to beta-cell destruction by the constitutively expressed FasL independent of an autoimmune reaction, thus providing a link between type 1 and type 2 diabetes.

Defective stimulus-secretion coupling in islets of Psammomys obesus, an animal model for type 2 diabetes

Psammomys obesus is a model of type 2 diabetes that displays resistance to insulin and deranged beta-cell response to glucose. We examined the major signaling pathways for insulin release in P. obesus islets. Islets from hyperglycemic animals utilized twice as much glucose as islets from normoglycemic diabetes-prone or diabetes-resistant controls but exhibited similar rates of glucose oxidation. Fractional oxidation of glucose was constant in control islets over a range of concentrations, whereas islets from hyperglycemic P. obesus showed a decline at high glucose. The mitochondrial substrates alpha-ketoisocaproate and monomethyl succinate had no effect on insulin secretion in P. obesus islets. Basal insulin release in islets from diabetes-resistant P. obesus was unaffected by glucagon-like peptide 1 (GLP-1) or forskolin, whereas that of islets of the diabetic line was augmented by the drugs. GLP-1 and forskolin potentiated the insulin response to maximal (11.1 mmol/l) glucose in islets from all groups. The phorbol ester phorbol myristic acid (PMA) potentiated basal insulin release in islets from prediabetic animals, but not those from hyperglycemic or diabetes-resistant P. obesus. At the maximal stimulatory glucose concentration, PMA potentiated insulin response in islets from normoglycemic prediabetic and diabetes-resistant P. obesus but had no effect on islets from hyperglycemic P. obesus. Maintenance of islets from hyperglycemic P. obesus for 18 h in low (3.3 mmol/l) glucose in the presence of diazoxide (375 pmol/l) dramatically improved the insulin response to glucose and restored the responsiveness to PMA. Immunohistochemical analysis indicated that hyperglycemia was associated with reduced expression of alpha-protein kinase C (PKC) and diminished translocation of lambda-PKC. In summary, we found that 1) P. obesus islets have low oxidative capacity, probably resulting in limited ability to generate ATP to initiate and drive the insulin secretion; 2) insulin response potentiated by cyclic AMP-dependent protein kinase is intact in P. obesus islets, and increased sensitivity to GLP-1 or forskolin in the diabetic line may be secondary to increased sensitivity to glucose; and 3) islets of hyperglycemic P. obesus display reduced expression of alpha-PKC and diminished translocation of lambda-PKC associated with impaired response to PMA. We conclude that low beta-cell oxidative capacity coupled with impaired PKC-dependent signaling may contribute to the animals' poor adaptation to a high-energy diet.

beta-cell glucotoxicity in the Psammomys obesus model of type 2 diabetes

Deficient insulin secretion and relative hyperproinsulinemia are characteristic features of type 2 diabetes. The gerbil Psammomys obesus appears to be an ideal natural model of the human disease because it shows increased tendency to develop diet-induced diabetes, which is associated with moderate obesity. The disease is characterized by initial hyperinsulinemia, progressing to hypoinsulinemia associated with depleted pancreatic insulin stores and an increased proportion of insulin precursor molecules in the blood and islets. Although the proinsulin translational efficacy was found to be increased in hyperglycemic animals, insulin mRNA levels were not augmented and exhibited a gradual decrease with disease progression. The development of hyperglycemia was associated with a transient increase in beta-cell proliferative activity, as opposed to a prolonged increase in the rate of beta-cell death, culminating in disruption of islet architecture. The hypothesis that glucotoxicity is responsible in part for these in vivo changes was investigated in vitro in primary islet cultures. Islets from diabetes-prone P. obesus cultured at high glucose concentrations displayed changes in beta-cell function that mimic those observed in diabetic animals. These changes include deficient insulin secretion, depleted insulin content, an increased proportion of insulin precursor molecules, a progressive increase of DNA fragmentation, and a transient proliferative response. Furthermore, insulin mRNA was not increased by short-term exposure of P. obesus islets to elevated glucose in vitro. It is proposed that beta-cell glucotoxicity in P. obesus results from the inability of proinsulin biosynthesis to keep pace with chronic insulin hypersecretion. The resulting depletion of the insulin stores may be related to deficient glucose-regulated insulin gene transcription, possibly due to defective PDX-1 (pancreatic duodenal homeobox factor-1) expression in the adult P. obesus. An additional glucotoxic effect involves the loss of beta-cell mass in hyperglycemic P. obesus as a result of progressive beta-cell death without an adequate increase in the rate of beta-cell proliferation.

Distinct effects of saturated and monounsaturated fatty acids on beta-cell turnover and function

Glucotoxicity and lipotoxicity contribute to the impaired beta-cell function observed in type 2 diabetes. Here we examine the effect of saturated and unsaturated fatty acids at different glucose concentrations on beta-cell proliferation and apoptosis. Adult rat pancreatic islets were cultured onto plates coated with extracellular matrix derived from bovine corneal endothelial cells. Exposure of islets to saturated fatty acid (0.5 mmol/l palmitic acid) in medium containing 5.5, 11.1, or 33.3 mmol/l glucose for 4 days resulted in a five- to ninefold increase of beta-cell DNA fragmentation. In contrast, monounsaturated palmitoleic acid alone (0.5 mmol/l) or in combination with palmitic acid (0.25 or 0.5 mmol/l each) did not affect DNA fragmentation. Increasing concentrations of glucose promoted beta-cell proliferation that was dramatically reduced by palmitic acid. Palmitoleic acid enhanced the proliferation activity in medium containing 5.5 mmol/l glucose but had no additional effect at higher glucose concentrations (11.1 and 33.3 mmol/l). The cell-permeable ceramide analog C2-ceramide mimicked both the palmitic acid-induced beta-cell apoptosis and decrease in proliferation. Moreover, the ceramide synthetase inhibitor fumonisin B1 blocked the deleterious effects of palmitic acid on beta-cell viability. Additionally, palmitic acid but not palmitoleic acid decreased the expression of the mitochondrial adenine nucleotide translocator and induced release of cytochrome c from the mitochondria into the cytosol. Finally, palmitoleic acid improved beta-cell-secretory function that was reduced by palmitic acid. Taken together, these results suggest that the lipotoxic effect of the saturated palmitic acid involves an increased apoptosis rate coupled with reduced proliferation capacity of beta-cells and impaired insulin secretion. The deleterious effect of palmitate on beta-cell turnover is mediated via formation of ceramide and activation of the apoptotic mitochondrial pathway. In contrast, the monounsaturated palmitoleic acid does not affect beta-cell apoptosis, yet it promotes beta-cell proliferation at low glucose concentrations, counteracting the negative effects of palmitic acid as well as improving beta-cell function.

Effect of inhibition of glutathione synthesis on insulin action: in vivo and in vitro studies using buthionine sulfoximine

Decreased cellular GSH content is a common finding in experimental and human diabetes, in which increased oxidative stress appears to occur. Oxidative stress has been suggested to play a causative role in the development of impaired insulin action on adipose tissue and skeletal muscle. In this study we undertook to investigate the potential of GSH depletion to induce insulin resistance, by utilizing the GSH synthesis inhibitor, L-buthionine-[S,R]-sulfoximine (BSO). GSH depletion (20-80% in various tissues), was achieved in vivo by treating rats for 20 days with BSO, and in vitro (80%) by treating 3T3-L1 adipocytes with BSO for 18 h. No demonstrable change in the GSH/GSSG ratio was observed following BSO treatment. GSH depletion was progressively associated with abnormal glucose tolerance test, which could not be attributed to impaired insulin secretion. Skeletal muscle insulin responsiveness was unaffected by GSH depletion, based on normal glucose response to exogenous insulin, 2-deoxyglucose uptake measurements in isolated soleus muscle, and on normal skeletal muscle expression of GLUT4 protein. Adipocyte insulin responsiveness in vitro was assessed in 3T3-L1 adipocytes, which displayed decreased insulin-stimulated tyrosine phosphorylation of insulin-receptor-substrate proteins and of the insulin receptor, but exaggerated protein kinase B phosphorylation. However, insulin-stimulated glucose uptake was unaffected by GSH depletion. In accordance, normal adipose tissue insulin sensitivity was observed in BSO-treated rats in vivo, as demonstrated by normal inhibition of circulating non-esterified fatty acid levels by endogenous insulin secretion. In conclusion, GSH depletion by BSO results in impaired glucose tolerance, but preserved adipocyte and skeletal muscle insulin responsiveness. This suggests that alternative oxidation-borne factors mediate the induction of peripheral insulin resistance by oxidative stress.

[Does modification of documentation result in a reduction of medication to involuntary patients?]

OBJECTIVE

The effects of modification of documentation on the administration of psychotropic medication to involuntary patients in hospital were investigated.

METHODS

The charts of 414 inpatients on the acute-ward were reviewed two months before and two months after a new form for documentation of rationales for medication administration to involuntary patients was instituted. A follow-up was carried out for a two-month period a year later.

RESULTS

The percentage of patients who received medication involuntarily, 70% of whom were schizophrenic, fell by over half, from 12% to 5%, after additional standardized documentation for the use of such medications was instituted. The number of medications administered to involuntary patients fell from 80 to 21, a reduction of 74%. The effects were stable over the course of one year.

CONCLUSIONS

Modification of documentation seems to reduce the use of medication with involuntary patients.