New High-Confinement Regime with Fast Ions in the Core of Fusion Plasmas

The key result of the present work is the theoretical prediction and observation of the formation of a new type of transport barrier in fusion plasmas, called F-ATB (fast ion-induced anomalous transport barrier). As demonstrated through state-of-the-art global electrostatic and electromagnetic simulations, the F-ATB is characterized by a full suppression of the turbulent transport-caused by strongly sheared, axisymmetric E×B flows-and an increase of the neoclassical counterpart, albeit keeping the overall fluxes at significantly reduced levels. The trigger mechanism is shown to be a mainly electrostatic resonant interaction between suprathermal particles, generated via ion-cyclotron-resonance heating, and plasma microturbulence. These findings are obtained by realistic simulations of the ASDEX Upgrade discharge No. 36637-properly designed to maximized the beneficial role of the wave-particle resonance interaction-which exhibits the expected properties of improved confinement produced by energetic particles.

Anaesthetics stop diverse plant organ movements, affect endocytic vesicle recycling and ROS homeostasis, and block action potentials in Venus flytraps

Background and Aims

Anaesthesia for medical purposes was introduced in the 19th century. However, the physiological mode of anaesthetic drug actions on the nervous system remains unclear. One of the remaining questions is how these different compounds, with no structural similarities and even chemically inert elements such as the noble gas xenon, act as anaesthetic agents inducing loss of consciousness. The main goal here was to determine if anaesthetics affect the same or similar processes in plants as in animals and humans.

Methods

A single-lens reflex camera was used to follow organ movements in plants before, during and after recovery from exposure to diverse anaesthetics. Confocal microscopy was used to analyse endocytic vesicle trafficking. Electrical signals were recorded using a surface AgCl electrode.

Key Results

Mimosa leaves, pea tendrils, Venus flytraps and sundew traps all lost both their autonomous and touch-induced movements after exposure to anaesthetics. In Venus flytrap, this was shown to be due to the loss of action potentials under diethyl ether anaesthesia. The same concentration of diethyl ether immobilized pea tendrils. Anaesthetics also impeded seed germination and chlorophyll accumulation in cress seedlings. Endocytic vesicle recycling and reactive oxygen species (ROS) balance, as observed in intact Arabidopsis root apex cells, were also affected by all anaesthetics tested.

Conclusions

Plants are sensitive to several anaesthetics that have no structural similarities. As in animals and humans, anaesthetics used at appropriate concentrations block action potentials and immobilize organs via effects on action potentials, endocytic vesicle recycling and ROS homeostasis. Plants emerge as ideal model objects to study general questions related to anaesthesia, as well as to serve as a suitable test system for human anaesthesia.

Observations of core ion cyclotron emission on ASDEX Upgrade tokamak

The B-dot probe diagnostic suite on the ASDEX Upgrade tokamak has recently been upgraded with a new 125 MHz, 14 bit resolution digitizer to study ion cyclotron emission (ICE). While classic edge emission from the low field side plasma is often observed, we also measure waves originating from the core with fast fusion protons or beam injected deuterons being a possible emission driver. Comparing the measured frequency values with ion cyclotron harmonics present in the plasma places the origin of this emission on the magnetic axis, with the fundamental hydrogen/second deuterium cyclotron harmonic matching the observed values. The actual values range from ∼27 MHz at the on-axis toroidal field B_T = -1.79 T to ∼40 MHz at B_T = -2.62 T. When the magnetic axis position evolves during this emission, the measured frequency values track the changes in the estimated on-axis cyclotron frequency values. Core ICE is usually a transient event lasting ∼100 ms during the neutral beam startup phase. However, in some cases, core emission occurs in steady-state plasmas and lasts for longer than 1 s. These observations suggest an attractive possibility of using a non-perturbing ICE-based diagnostic to passively monitor fusion alpha particles at the location of their birth in the plasma core, in deuterium-tritium burning devices such as ITER and DEMO.

A new compact solid-state neutral particle analyser at ASDEX Upgrade: Setup and physics modeling

At ASDEX Upgrade (AUG), a new compact solid-state detector has been installed to measure the energy spectrum of fast neutrals based on the principle described by Shinohara et al. [Rev. Sci. Instrum. 75, 3640 (2004)]. The diagnostic relies on the usual charge exchange of supra-thermal fast-ions with neutrals in the plasma. Therefore, the measured energy spectra directly correspond to those of confined fast-ions with a pitch angle defined by the line of sight of the detector. Experiments in AUG showed the good signal to noise characteristics of the detector. It is energy calibrated and can measure energies of 40-200 keV with count rates of up to 140 kcps. The detector has an active view on one of the heating beams. The heating beam increases the neutral density locally; thereby, information about the central fast-ion velocity distribution is obtained. The measured fluxes are modeled with a newly developed module for the 3D Monte Carlo code F90FIDASIM [Geiger et al., Plasma Phys. Controlled Fusion 53, 65010 (2011)]. The modeling allows to distinguish between the active (beam) and passive contributions to the signal. Thereby, the birth profile of the measured fast neutrals can be reconstructed. This model reproduces the measured energy spectra with good accuracy when the passive contribution is taken into account.

Multi-view fast-ion D-alpha spectroscopy diagnostic at ASDEX Upgrade

A novel fast-ion D-alpha (FIDA) diagnostic that is based on charge exchange spectroscopy has been installed at ASDEX Upgrade. The diagnostic uses a newly developed high-photon-throughput spectrometer together with a low-noise EM-CCD camera that allow measurements with 2 ms exposure time. Absolute intensities are obtained by calibrating the system with an integrating sphere and the wavelength dependence is determined to high accuracy using a neon lamp. Additional perturbative contributions to the spectra, such as D2-molecular lines, the Stark broadened edge D-alpha emission, and passive FIDA radiation have been identified and can be subtracted or avoided experimentally. The FIDA radiation from fast deuterium ions after charge exchange reactions can therefore be analyzed continuously without superimposed line emissions at large Doppler shifts. Radial information on the fast ions is obtained from radially distributed lines of sight. The investigation of the fast-ion velocity distribution is possible due to three different viewing geometries. The independent viewing geometries access distinct parts of the fast-ion velocity space and make tomographic reconstructions possible.

Cleavage of the IPS-1/Cardif/MAVS/VISA does not inhibit T cell-mediated elimination of hepatitis C virus non-structural 3/4A-expressing hepatocytes

BACKGROUND

Hepatitis C virus (HCV) effectively establishes persistent infection in human livers. The non-structural (NS) 3/4A complex participates in this process by cleavage of interferon beta (IFN beta) promoter stimulator-1 (IPS-1; also termed Cardif/MAVS/VISA), which inhibits responses to double stranded (ds) RNA. However, it is not known whether this effect extends beyond innate responses.

AIMS

To test if HCV NS3/4A affects innate and adaptive immune responses in vivo.

METHODS

NS3 levels were semi-quantified in human liver biopsies, transfected cells, and in transgenic (Tg) mouse livers by western blot. The effect of NS3/4A on dsRNA-mediated signalling and on the integrity of IPS-1 was analysed using in vitro translation, transfected cells and Tg mice. Cytotoxic T cell (CTL)-mediated clearance of transient firefly luciferase (FLuc)- and/or NS3/4A-Tg hepatocytes was determined using in vivo imaging and western blot.

RESULTS

NS3 protein levels were in a comparable range (0.1-49 microg/g tissue) in infected human livers and Tg mouse livers. Importantly, these levels of NS3/4A reduced murine innate responses to synthetic dsRNA in vivo, supporting the possibility that this occurs also in infected humans. The likely explanation for this was the NS3/4A-mediated cleavage of mouse IPS-1, albeit less efficiently than human IPS-1. Despite this, FLuc- and/or NS3/4A-expressing murine hepatocytes were effectively eliminated by hepatic CTLs, utilising the classical molecules for virus-infected cell lysis, including CD8, IFN gamma, perforin and FasL.

CONCLUSIONS

Although HCV NS3/4A inhibits the innate immunity, this does not prevent CTL-mediated clearance of NS3/4A-expressing hepatocytes in vivo. Thus, other HCV proteins are most likely responsible for interfering with the adaptive immunity.

The hepatitis C virus and immune evasion: non-structural 3/4A transgenic mice are resistant to lethal tumour necrosis factor alpha mediated liver disease

BACKGROUND

The hepatitis C virus (HCV) establishes chronic infection by incompletely understood mechanisms. The non-structural (NS) 3/4A protease/helicase has been proposed as a key complex in modulating the infected hepatocyte, although nothing is known about the effects this complex exerts in vivo.

AIM

To generate mice with stable and transient hepatocyte expression of the HCV NS3/4A proteins to study its effects in vivo.

METHODS

NS3/4A expression was determined by western blot and immunohistochemistry. Two independent pathologists determined the liver histology. Hepatic immunity was characterised by quantifying intrahepatic immune cell subsets. Liver damage was induced using carbon tetrachloride (CCl(4)), lipopolysaccaride (LPS), tumour necrosis factor alpha (TNFalpha), and anti-Fas antibody.

RESULTS

Expression of NS3/4A was restricted to the cytoplasm of hepatocytes, and did not cause liver cancer or any spontaneous liver pathology. However, the presence of NS3/4A modulated the intrahepatic immunity, as follows: first, the CD4+ T cell and type I/II dendritic cell subsets were reduced in transgenic livers; second, NS3/4A protected hepatocytes from liver damage mediated in vivo by CCl(4), LPS, TNFalpha, but not FAS; and third, both stable and transiently NS3/4A transgenic mice were resistant to lethal doses of liver targeted TNFalpha, and the resistance could be reverted by treatment with a p38 mitogen activated protein kinase inhibitor (MAPK).

CONCLUSIONS

Hepatic expression of NS3/4A does not induce spontaneous liver disease. NS3/4A does, however, alter the intrahepatic immune cell subsets and protects hepatocytes against TNFalpha induced liver damage in vivo. The TNFalpha resistance can be reverted by treatment with a p38 MAPK inhibitor. This represents a new immune evasion strategy conferred by NS3/4A.

Secretory antibodies against Giardia intestinalis in lactating Nicaraguan women

Secretory IgA (sIgA) antibodies are important in the host defence against the intestinal protozoan parasite Giardia intestinalis. However, few antigens have been identified. In this study 100 milk and saliva samples from lactating women, living in an endemic region (León, Nicaragua), were screened for the presence of antibodies against G. intestinalis. Most milk and saliva samples contained anti-Giardia antibodies (59% and 52%, respectively), with a mean sIgA content 50 times higher in milk than in saliva. The positive samples reacted with trophozoite membrane, flagella and cytoplasmic antigens. Western blot analysis showed that milk and saliva anti-Giardia sIgA recognized up to 16 different Giardia proteins in the molecular weight region 20-165 kDa. Two-dimensional Western blotting showed that the major immunoreactive proteins were the same as the immunoreactive proteins identified by serum from acute giardiasis patients in a non-endemic country. The major difference was a stronger reactivity against the variant surface proteins (VSPs) in the milk samples. Milk sIgAs also recognized recombinant Giardia proteins such as alpha-1 giardin, ornithine carbamoyl transferase, VSP-4EX, arginine deaminase and alpha-enolase. These antigens will be important targets in the development of new immunodiagnostic tools and vaccines.

Size of pancreatic islets of Langerhans: a key parameter for viability after cryopreservation

Large amounts and excellent viabilities of pancreatic islets are prerequisites for recent advances in islet transplantation. Cryopreservation has been shown to enlarge transplanted cell mass, but has been accompanied by reduced viability. In this study rat pancreatic islets were differentiated into small (<200 micro m), medium (200-400 micrometers) and large (>400 micrometers) categories and their susceptibilities to different freezing conditions were evaluated: concentration of cryoprotectant (0.7-3.1 M), equilibration (15 vs. 45 min, 22 degrees C vs. on ice) and post-thaw removal of cryoprotectant (15 vs. 30 min, stepwise vs. one-step). The most prominent finding was a negative correlation between islet size and viability observed in non-frozen islets to a minor degree (r=-0.44) and significantly enhanced after cryopreservation (r<-0.8). The concentration of cryoprotectant showed the most significant influence on viability affecting small, medium and large islets. Different techniques of equilibration with the cryoprotectant resulted in significant changes of islet viability of medium islets, whereas small and large islets were unaffected. For different techniques of removal of the cryoprotectant, no significant influence on viabilities was found. We conclude that large islets represented a highly susceptible population concerning damage due to cryopreservation.

Risk factors, prevention methods, and wound care for patients with pressure ulcers

The purposes of this study about patients with pressure ulcers were to: (a) examine demographic characteristics, laboratory values, Braden Scale scores, and presence of pressure ulcer prevention methods and (b) examine pressure ulcers in terms of classification, stage, wound care, and documentation. The investigation was a prospective, descriptive study; the methods used were patient observations and data recordings from the medical record. Of the patients followed (n = 694), 71 had pressure ulcers. Patients with pressure ulcers were significantly older, with longer lengths of stay, more comorbid conditions, lower blood hemoglobin, lower serum albumin, higher white blood cell counts, and lower Braden Scale scores than patients without pressure ulcers. The presence of pressure ulcer prevention methods was greatly lacking. Nosocomial pressure ulcers tended to be a lower stage compared with pressure ulcers present on admission. Dressings used for wound care were generally gauze or a hydrocolloid. Nurses' charting about pressure ulcers was complete for only 35% of notations. The results of this study indicate that advanced practice nurses have a critical role in caring for patients with pressure ulcers and educating care providers.

[3-dimensional surface measurement of spinal deformities with video rasterstereography]

QUESTION

Video rasterstereography is a method for back surface measurement comprising automatic back surface reconstruction and shape analysis. Aim of this prospective study was to determine the accuracy of this method in comparison to the conventional frontal and lateral standing radiographs.

METHOD

95 patients with idiopathic scoliosis or scoliotic postural abnormalities and 18 patients with thoracic hyperkyphosis and Scheuermann's disease were investigated. The Cobb angles, the sagittal profile and apical vertebral rotation as well as pelvic obliquity and trunk decompensation were measured. The analysis was carried out by two independent observers.

RESULTS

The root mean square (r.m.s.) deviation of the Cobb angle in the cases of idiopathic scoliosis ranged between 7 degrees and 8 degrees. In video rasterstereography there were no false negative results and two false positive results concerning differentiation between structural scoliosis and scoliotic postural abnormality. The r.m.s. deviation of apical vertebral rotation averaged 7.9 degrees and for pelvic obliquity respectively trunk imbalance 0.65 cm respectively 1.07 cm. The thoracic hyperkyphosis in Scheuermann's disease showed a r.m.s. deviation of 5.6 degrees.

CONCLUSIONS

Video rasterstereography is a reliable method in the three-dimensional evaluation of spinal deformities and constitutes a valuable additional tool to the clinical examination and can reduce the number of radiographs.

Pressure ulcer prevention within 72 hours of admission in a rehabilitation setting

This prospective study followed 91 patients in an acute rehabilitation facility from admission until discharge. Of these patients, 35 patients were initially assessed at-risk for pressure ulcers. Demographics, risk status, and pressure ulcer prevention strategies were examined and assessed for at-risk and not at-risk patients. At-risk patients had significantly more medical diagnoses and longer hospitalizations than not at-risk patients, but did not differ by sex, race or age. The following pressure ulcer prevention strategies were considered for both at-risk and not at-risk patients within the first three days of admission: pressure-reducing bed surface, pillows for positioning, lift sheet, heel protection, posted turning schedule, pressure ulcer prevention care plan, pressure ulcer prevention charted, and pressure ulcer prevention educational materials at the bedside. Only the use of pillows for positioning was significant between the two groups; all other preventive strategies were comparable between both groups. For at-risk patients, it is necessary to implement pressure ulcer prevention strategies as early as possible after admission since pressure ulcers may quickly develop.

Presence of pressure ulcer prevention methods used among patients considered at risk versus those considered not at risk

PURPOSE

This study examined pressure ulcer-prevention strategies available for patients considered at risk versus those considered not at risk.

DESIGN

The study used a prospective, longitudinal design.

SETTING AND SUBJECTS

Six hundred ninety-four patients from units of five acute care hospitals, a rehabilitation facility, and two nurses' home care caseloads participated in the investigation.

INSTRUMENTS

Data-collection instruments included the Braden Scale for risk assessment, demographic information, and the Pressure Ulcer-Prevention Strategies tool, which assessed for the presence of 16 pressure ulcer-prevention strategies.

METHODS

All patients admitted to a participating unit during a 2-month period were followed up until discharge. Depending on the site, patients were assessed for the presence of pressure ulcer-prevention strategies one to three times per week.

RESULTS

Patients in the at-risk group versus those in the not-at-risk group were more likely (p < 0.01) to have the head of the bed in a low position, a pressure-reducing bed surface, pressure ulcer prevention charted, a positioning wedge, incontinence cleanser and ointment, heel protection, a prevention care plan, a trapeze, and a posted turning schedule. The at-risk group had significantly (p < 0.01) more prevention strategies present than did the not-at-risk group. However, the percentage of patients placed on a pressure ulcer-prevention program was low for both groups.

CONCLUSIONS

Pressure ulcer prevention was evident for the at-risk group, but at a low rate. Institutions must continue to explore this critical area affecting patient outcomes.

Occurrence of skin lesions/conditions in ill persons

The purpose of this study was to examine the occurrence of common skin lesions that potentially may be misdiagnosed as a pressure ulcer, and to examine the characteristics of ill persons who have these skin changes. This was a prospective, descriptive study which included five acute care hospitals, a rehabilitation hospital, and a home care agency. Results indicated that patients with skin lesions/conditions were significantly older and had longer lengths of stay, more diseases, lower Braden Scale scores, and lower serum albumin levels. Nurses must gain knowledge about identifying and treating skin conditions. Assessment of the patient's skin should occur throughout their length of stay.

Water-soluble conductive polymer homogeneous immunoassay (SOPHIA). A novel immunoassay capable of automation

Conductive polymers are extensively conjugated macromolecules able to conduct electricity in their doped state and having a UV-visible spectrum which undergoes important chromatic modifications when subjected to pH changes or to oxido-reductive processes. This article describes a novel homogeneous immunoassay in which a water-soluble conductive polymer is used as the label. When antigen-antibody binding occurs, the local pH near the complex is modified. Such a pH change is in turn able to induce modifications in the absorbance at a characteristic wavelength of a conductive polymer covalently linked to either the antigen or the antibody. Consequently, the extent of tracer binding can be directly monitored by photometry during incubation. We present examples which validate the concept and exemplify its applicability in quantitative competitive immunoassays for human C-reactive protein and human serum albumin, as performed in a Cobas-Mira automated analyzer.

Melatonin decreases the amplitude of the b-wave of the human electroretinogram

In a double-blind placebo crossover study of 13 healthy volunteers, the pineal hormone melatonin (10 mg) was given at 4 pm, and the electroretinogram measured under conditions of dark and light adaptation. A significant diminution of b-wave amplitude was found under both photopic (delta = 5.4 microV, p < 0.05) and scotopic conditions (delta = 7.4 microV, p < 0.01). These data indicate that melatonin may transduce the dark signal at the level of the retina as well as the pineal. Acute administration of melatonin decreases sensitivity to light.

Heterogeneity of insulin receptors in rat tissues as detected with the partial agonist B29,B29'-suberoyl-insulin

Using the insulin receptor partial agonist B29,B29'-suberoyl-insulin, a covalently dimerized insulin derivative, we previously demonstrated a heterogeneity of signal transduction by insulin receptors in two cell systems. The present study was designed to characterize the heterogeneity of insulin receptors in different rat tissues with this agent. Binding of 125I-insulin to insulin receptors and its inhibition by B29,B29'-suberoyl-insulin or by unlabeled insulin were assayed in plasma membranes from brain, spleen, adipocytes, and liver. IC50 values of B29,B29'-suberoyl-insulin were different in all tissues investigated (brain < spleen < adipocytes < liver). In contrast, IC50 values of insulin were identical, with the exception of spleen membranes (spleen < brain = adipocytes = liver). Furthermore, the IC50 ratios (B29 dimer/insulin) were significantly different, ranging from 0.7 (brain) to 12.8 (liver). Solubilization and partial purification of insulin receptors failed to abolish the marked difference between brain and liver (IC50 ratios of 1.8 and 7.1, respectively). The apparent molecular masses of the alpha subunits of insulin receptors, as labeled with a photoreactive insulin derivative, appeared identical in liver and spleen but were significantly lower in adipocytes and brain (liver = spleen > adipocytes > brain). The tissue-specific expression of the known insulin receptor isoforms generated by alternative splicing (insulin receptor types A and B), as assessed by polymerase chain reaction amplification with oligonucleotide primers flanking exon 11, was not correlated with the differences in the IC50 values and ratios for insulin and B29,B29'-suberoyl-insulin. Furthermore, IC50 values of both insulin and the B29 dimer were 3-fold lower in membranes from Rat1 cells overexpressing insulin receptor type A, compared with membranes with insulin receptor type B; the IC50 ratios were identical. No additional alternative splicing of insulin receptor mRNA was found by polymerase chain reaction amplification and digestion with HaeIII and AluI of seven overlapping domains of the receptor alpha subunit. These data suggest a heterogeneity of insulin receptors in rat tissues that is unrelated to alternative splicing of the insulin receptor gene.

Effectiveness of colorectal cancer screening: results from a population-based case-control evaluation in Saarland, Germany

In order to evaluate the effectiveness of colorectal cancer screening by the faecal occult blood test (FOBT) in Germany a population-based case-control study was conducted in Saarland, a southwestern state of Germany. As cases, we identified 522 persons (244 males, 278 females) who died of colorectal cancer between 1983 and 1986 between the ages of 55 and 75 years. For 163 male cases complete screening histories were retrieved together with up to five age-matched controls who had not died of colorectal cancer identified from the files of the case's referring general practitioner (GP). For 209 female cases screening histories were retrieved from their GPs and gynaecologists as well as for age-matched controls. Individual screening histories were established with emphasis on identifying whether FOBTs were carried out asymptomatically or symptomatically. In the time period 6-36 months prior to diagnosis 13% of the male cases and 14% of the male controls had at least one asymptomatic FOBT with a corresponding matched odds ratio of 0.92 (95% CI: 0.61, 1.75). For the same prediagnostic period 16% of the female cases and 29% of the female controls had at least one asymptomatic FOBT leading to an odds ratio of 0.43 (95% CI: 0.27, 0.68). Thus, for males where participation rates are generally low, no protective effect could be seen but for females where participation rates are higher a clear protective effect is seen. Possibilities for bias need to be taken into consideration when interpreting these results. Organizational measures ensuring a high penetrance of a mass screening programme are seen as a way to elevate efficacy.

Biphasic alteration of glucose transport in 3T3-L1 cells during differentiation to the adipocyte-like phenotype

Glucose transport activity and subcellular distribution of glucose transporters, GLUT1 and GLUT4 were studied in non-confluent (NCF), confluent (CF), and differentiated 3T3-L1 cells (A). During growth of the fibroblasts to confluence, basal transport activity decreased to 20% of that in non-confluent cells. Corresponding with the reduction in transport activity, the abundance of GLUT1 in plasma membranes as normalized per cell decreased by 75% during growth of the cells to confluence. This effect was mainly due to a reduction of total cellular GLUT1. In addition, the portion of GLUT1 located in intracellular vesicles (low-density microsomes) was moderately increased in confluent cells, and was further increased in cells differentiated to the adipocyte-like phenotype (in NCF 11%, in CF 24.5%, and in A 60% of the total GLUT1). GLUT4, in contrast, was approximately 10-times more abundant in low-density microsomes than in the plasma membranes of the differentiated cells. Insulin failed to stimulate glucose transport activity in non-confluent cells but produced an approximately 2-fold stimulation in confluent cells, probably through translocation of the GLUT1 from the intracellular compartment to the plasma membrane. In the differentiated adipocytes, insulin stimulated a 10-fold increase in glucose transport activity, the maximum levels approaching basal transport rates of non-confluent cells; both GLUT1 and GLUT4 were translocated in response to insulin. These data indicate that insulin sensitivity in 3T3-L1 cells develops in a biphasic pattern. In confluent fibroblasts, a moderate effect of insulin conferred exclusively by GLUT1 is detectable, probably reflecting the small intracellular compartment of GLUT1.(ABSTRACT TRUNCATED AT 250 WORDS)

The signaling potential of the receptors for insulin and insulin-like growth factor I (IGF-I) in 3T3-L1 adipocytes: comparison of glucose transport activity, induction of oncogene c-fos, glucose transporter mRNA, and DNA-synthesis

The receptors for insulin and insulin-like growth factor I (IGF-I) have in common a high sequence homology and diverse overlapping functions, (e.g., the stimulation of acute metabolic events and the induction of cell growth.). In the present study, we have compared the potential of insulin and IGF-I receptors in stimulating glucose transport activity, glucose transporter gene expression, DNA-synthesis, and expression of proto-oncogene c-fos in 3T3-L1 adipocytes which express high levels of both receptors. Binding of both hormones to their own receptors was highly specific as compared with binding to the respective other receptor (insulin receptor: KD = 3.6 nM, KI of IGF-I greater than 500 nM; IGF-I receptor, KD = 1.1 nM, KI of insulin = 191 nM). Induction of proto-oncogene c-fos mRNA by insulin and IGF-I paralleled their respective receptor occupancy and was thus induced by both hormones via their own receptor (EC50 of insulin, 3.7; IGF-I, 3.9 nM). Similarly, both insulin and IGF-I increased DNA synthesis (EC50 of insulin, 5.8 nM; IGF-I, 4.0 nM), glucose transport activity (EC50 of insulin, 1.7 nM; IGF-I, 1.4 nM), and glucose transporter (GLUT4) mRNA levels in concentrations corresponding with their respective receptor occupancy. These data indicate that in 3T3-L1 cells the alpha-subunits of insulin and IGF-I receptors have an equal potential to stimulate a metabolic and a mitogenic response.

[Toxicological assessment of amalgam components released in immersion tests]

After immersion of unpolished and polished high copper amalgam in saliva with different pH values for up to 12 weeks, the elements mercury, tin, copper, silver and antimony were analysed in the solution. Unpolished amalgam corroded more than polished amalgam. Corrosion increased with the time of immersion and the acidity of the solution. The values calculated to a maximum of clinical application not imply any toxicologic risk.

Development of the hormone-sensitive glucose transport activity in differentiating 3T3-L1 murine fibroblasts. Role of the two transporter species and their subcellular localization

The development of a hormone-responsive glucose transport activity during differentiation of 3T3-L1 murine fibroblasts to an insulin-sensitive adipocyte-like phenotype was studied. Glucose transport activity was insensitive to insulin or insulin-like growth factor I (IGF-I) before differentiation, and was increased by 8-10-fold after differentiation by both insulin and IGF-I via their own respective receptors. In contrast, in undifferentiated cells insulin and IGF-I stimulated a large increase of [3H]thymidine incorporation into DNA via IGF-I receptors, indicating that undifferentiated 3T3-L1 cells are equipped with fully functioning hormone (IGF-I) receptors. Thus the previously described increase in expression of insulin receptors during differentiation cannot solely account for the development of hormone-sensitive glucose transport in the 3T3-L1 cell. The total glucose transport activity reconstituted from membrane fractions was increased by about 3-fold during differentiation. In differentiated cells, more than 80% of the total reconstitutable glucose transport activity was detected in an intracellular compartment (200,000 g microsomes) as compared with about 20% in undifferentiated cells. Immunoblots with specific antiserum confirmed previous reports indicating that the adipose tissue/muscle glucose transporter (GT3) was exclusively present in the differentiated cells, whereas the erythrocyte/brain glucose transporter (GT1) was detected in both differentiated and undifferentiated cells. Upon differentiation, GT1 was redistributed from plasma membranes to the intracellular compartment. In addition, the newly formed GT3 was predominantly found (greater than 80% of total) in the microsomal fraction of differentiated cells. Both GT1 and GT3 appeared to be hormone-sensitive, since in differentiated cells insulin as well as IGF-I gave rise to their translocation from the intracellular compartment to the plasma membrane. These data suggest that, in addition to the specific expression of the GT3 transporter, the formation of a large pool of intracellular glucose transporters comprising both GT1 and GT3 contributes to the development of insulin sensitivity in the 3T3-L1 cell.

[Electrochemical examinations to the influence of mechanical treatment of surfaces on the corrosion on different dental amalgams. 2: Measurements of potentiodynamic polarization with high polarization rate]

In a cell with artificial saliva the electrochemical behaviour of amalgam specimens of Germadent, Duragam and ANA 2000 are characterized in dependence of different mechanical treatments of surfaces using cycling voltimetry. In the beginning the influence of roughness on the corrosion is evident, but increasing the influence of chemical composition dominant. Duragam-amalgam is most resistant to corrosion. The content of copper in Duragam has a better effect than the high content of copper in ANA 2000.

[Clinical evaluation of the amalagam restorations for cavities Class I and Class II. 3: Comparison between dental school and dental institutions in the community]

Comparison of conventional amalgam restorations produced either in dental college by students or in out-patient department showed that the portion of clinical acceptable restorations was higher at the college. The frequency of secondary caries was distinctively higher in the out-patient department (28.2%) than in the college (16.4%). Secondary caries mainly caused unacceptable quality of fillings of both the institutions. Causes brought about by material defect prevailed at the dental school. In the community errors of preparation mainly led to secondary caries.

Antagonistic effects of a covalently dimerized insulin derivative on insulin receptors in 3T3-L1 adipocytes

In the present study we describe the antagonistic effects of the covalently dimerized insulin derivative B29,B29'-suberoyl-insulin on insulin receptors in 3T3-L1 mouse cells. In differentiated 3T3-L1 adipocytes, the derivative fully inhibits binding of 125I-labeled insulin to its receptor with about the same affinity as unlabeled insulin. In contrast, the dimerized derivative only partially (approximately 20%) mimics insulin's effects on glucose transport and DNA synthesis in the absence of insulin. In the presence of insulin, the agent competitively inhibits insulin-stimulated DNA synthesis ([3H]thymidine incorporation into total DNA), glucose transport activity (2-deoxyglucose uptake rate), and insulin receptor tyrosine kinase activity. In rat adipocytes, in contrast, the dimerized derivative stimulates glucose transport (initial 3-O-methylglucose as well as 2-deoxyglucose uptake rates) to the same extent as insulin does, and it fails to inhibit the effect of insulin. The data indicate that the dimerized insulin derivative B29,B29'-suberoyl-insulin is an insulin receptor antagonist (partial agonist) which retains a moderate intrinsic activity. The effects of this agent reveal a striking difference in insulin receptor-mediated stimulation of glucose transport between 3T3-L1 fatty fibroblasts and the mature rat adipocyte.

[Clinical morphology of bond zone in bonding agent composite systems]

Three composites--Colténe DRS, P-10, Silux--and their bonding agents (enamel bond systems, Scotchbond) have been investigated. To this purpose the usual examination of "margin close" according to Lutz in 1977 was modified in "morphology of bond zone" (bm). After one year the phosphonated bonding agents has shown better results dependent on composites than enamel bond systems. A year later the "bons zoné's morphology" of various composites did not differ from another because P-10 underlied a heavy occlusal wear. In spite of that the phosphonated bond to enamel has proven better results than to dentin. Replication technique was applied in some chosen cases with clinical acceptable bond zones.

[Clinical evaluation of amalgam restorations for Class I cavities and Class II. Part II: Cause analysis of unacceptable restorations]

627 not acceptable amalgam restorations using conventional alloy were investigated. Main failure was the secondary caries (60%) which was caused more by failures of preparations than by failures of material. New caries led to replacement of fillings in 16%. Fractures of restorations (13%) and unacceptable forms of fillings (9%) had a relative important position. The clinicians can influence 75 percent of the causes. With regard to material improvement, the results are discussed to avoid failures in therapy.