Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Using δ13C of Levoglucosan As a Chemical Clock

Compound specific carbon isotopic measurements (δ¹³C) of levoglucosan were carried out for ambient aerosol sampled during an intensive biomass burning period at different sites in Guangdong province, China. The δ¹³C of ambient levoglucosan was found to be noticeably heavier than the average δ¹³C of levoglucosan found in source C3-plant-combustion samples. To estimate the photochemical age of sampled ambient levoglucosan, back trajectory analyses were done. The origin and pathways of the probed air masses were determined, using the Lagrangian-particle-dispersion-model FLEXPART and ECMWF meteorological data. On the other hand, the isotopic hydrocarbon clock concept was applied to relate the changes in the field-measured stable carbon isotopic composition to the extent of chemical processing during transport. Comparison of the photochemical age derived using these two independent approaches shows on average good agreement, despite a substantial scatter of the individual data pairs. These analyses demonstrate that the degree of oxidative aging of particulate levoglucosan can be quantified by combining laboratory KIE studies, observed δ¹³C at the source and in the field, as well as back trajectory analyses. In this study, the chemical loss of levoglucosan was found to exceed 50% in one-fifth of the analyzed samples. Consequently, the use of levoglucosan as a stable molecular tracer may underestimate the contribution of biomass burning to air pollution.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Abstract PD3-04: PAK-1 amplified breast cancer cell lines are preferentially sensitive to PAK inhibition with G-5555

The small GTP-binding proteins Rac1 and Cdc42 stimulate activity of the serine/threonine kinase p21-activated kinase-1 (PAK-1) to drive growth factor signaling networks and Ras-driven tumorigenesis. Genomic amplification and over-expression of PAK1 are prevalent in luminal breast cancer and correlate with poor clinical outcome. Here we use a novel and selective small molecule inhibitor, G-5555, of the group I PAKs (PAK1, 2, and 3) to evaluate the importance of PAK1 in promoting growth of PAK1 amplified breast cancer cells. Cell lines with amplification of PAK1 were found to be more sensitive to PAK1 inhibition than non-amplified cell lines. Additionally, reverse phase protein array (RPPA) was used to assess the effects of PAK1 inhibition on a wide range of signaling pathways in both amplified and non-amplified cell lines. Reduced levels of phosphorylation of MEK S298 was observed in all cell lines exposed to G-5555 irrespective of amplification status, consistent with PAK1 inhibition in these cell lines. However, modulation of this downstream PAK1 substrate did not correlate with inhibition of cell proliferation or induction of cell death. Cell lines that showed inhibition of proliferation in response to G-5555 also showed enhanced levels of cell death along with apoptosis. Moreover, G-5555 reduced tumor growth in the PAK1 amplified MDA-MB-175 xenograft tumor model. Finally, we compared the in vitro activity of G-5555 with palbociclib, a recently approved inhibitor of the cyclin-dependent kinases CDK4 and CDK6, in PAK1 amplified luminal breast cancer cell lines. Our data supports PAK1 as an attractive target in PAK1 amplified cells and tumors and suggests that inhibiting PAK1 rather than CDK4/6 in this context may be a more attractive therapeutic strategy.

Citation Format: Ong CC, Blackwood E, Jakubiak D, Daemen A, Ramaswamy S, Heise C, Schmidt M, Sanders L, Wilson TR, Huw L, Ndubaku C, Rudolph J, Hoeflich KP, Friedman L, O'Brien T. PAK-1 amplified breast cancer cell lines are preferentially sensitive to PAK inhibition with G-5555. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD3-04.

Der Einfluß von Sauerstoff, Wasserstoff und Wasserdampf auf die elektrische Leitfähigkeit von Bariumoxyd und Barium ⸗ Strontiumoxyd

Die elektrische Leitfähigkeit σ von BaO bzw. (Ba. Sr) O in O2, die dem Thermokraftvorzeichen nach eine Defektleitung ist, steigt bei Temperaturen über ∼ 1000°K mit dem Sauerstoffdruck PO 2 entsprechend σ ∼ PO 2 ⅙ an. Die Gegenwart höher- oder niedrigerwertiger Ionen beeinflußt diese Abhängigkeit in charakteristischer Weise: Durch die Gegenwart der einwertigen Alkaliionen wird die p-Leitung in O2 stark erhöht, und σ wird über einen größeren PO 2-Bereich druckunabhängig. Die höherwertigen Ionen Y3+ oder La3+ erniedrigen σ in 02 etwas unter gleichzeitiger Veränderung der Druckabhängigkeit gemäß σ ∼ PO 2 1/x mit x &lt; 5. Bei Temperaturen &lt; 1000°K treten in O2 und in Gegenwart von Wasserdampfspuren sehr große Leitfähigkeitserhöhungen auf, die offenbar mit der Bildung von Peroxyden im Zusammenhang stehen. In H2 liegt beim (Ba, Sr) O Überschußleitung vor. die sich mit dem Druck gemäß σ ∼ PH 2 ¼ ändert. Auch die Elektronenemission ist unter bestimmten Bedingungen reversibel vom Druck den H, abhängig. Der Zusammenhang zwischen Leitfähigkeit und Fremdgasdruck sowie der Einfluß von Fremdionen wird diskutiert.

Über den Leitungsmechanismus oxydischer Halbleiter bei hohen Temperaturen

Die Leitfähigkeit σ oxydisdier Halbleiter in Gegenwart von Sauerstoff wird bei hohen Temperaturen und nicht zu großen Störstellenkonzentrationen nicht allein durch die thermische Abspaltung von Trägern aus den Störstellen, sondern in entscheidendem Maße auch durch eine von der Temperatur T und vom Sauerstoffdruck PO2 abhängige Veränderung der Störstellenkonzentration als Folge einer Wechselwirkung mit der umgebenden Atmosphäre bestimmt.

Bei Oxyden von Kationen mit abgesättigter Valenz sind dabei zwei Verhaltensweisen kennzeichnend: (a) Zunehmende Aufnahme von überschüssigem Sauerstoff im Kristall mit steigendem Druck - trotz begrenzter Kationenvalenz - und Ausbildung einer p-Leitung (σ ∼ PO2 1/x); (b) Dissoziation unter Abspaltung von Sauerstoff und Ausbildung einer n-Leitung (σ ∼ PO2 -1/x). Wie an Hand von Leitfähigkeitsmessungen als Funktion der Temperatur und des Sauerstoffdruckes sowie auf Grund von Thermokraftmessungen gezeigt wird, sind typische Vertreter für (a): BaO, SrO, CaO, ThO2, ZrO2 und La2O3, für (b) z. B. CeO2, TiO2 und ZnO. Durch Dotierung mit anderwertigen Kationen können unter normalen Meßbedingungen p-leitende Oxyde der Gruppe (a) auch in n-leitendem Zustand sowie normalerweise n-leitende Oxyde der Gruppe (b), z. B. TiO2 und ZnO, auch im p-leitenden Zustand erhalten werden. In eng durch T und PO2 begrenzten Bereichen treten dabei auch Eigenleitungszustände auf.

Es wird ein allgemeines, aus dem Massenwirkungsgesetz abgeleitetes Schema von Leitfähigkeits-Sauerstoffdruck-Isothermen angegeben, das viele Einzelheiten im Erscheinungsbild der oxydischen Halbleiter zu erklären vermag

Interferometry with Bose-Einstein condensates in microgravity

Atom interferometers covering macroscopic domains of space-time are a spectacular manifestation of the wave nature of matter. Because of their unique coherence properties, Bose-Einstein condensates are ideal sources for an atom interferometer in extended free fall. In this Letter we report on the realization of an asymmetric Mach-Zehnder interferometer operated with a Bose-Einstein condensate in microgravity. The resulting interference pattern is similar to the one in the far field of a double slit and shows a linear scaling with the time the wave packets expand. We employ delta-kick cooling in order to enhance the signal and extend our atom interferometer. Our experiments demonstrate the high potential of interferometers operated with quantum gases for probing the fundamental concepts of quantum mechanics and general relativity.

Is 6 months of neuroleptic withdrawal sufficient to distinguish drug-induced parkinsonism from Parkinson's disease?

BACKGROUND

Drug-induced parkinsonism (DIP) is the second commonest cause of akinetic-rigid syndrome in the western world. Differentiating DIP from Parkinson's disease (PD) may be a challenge to clinicians. One of the factors distinguishing DIP from PD is that discontinuation of the neuroleptic agent in DIP should relieve the symptoms of parkinsonism. The majority of the literature uses the 6-month timeframe between the neuroleptic withdrawal and resolution of the symptoms of parkinsonism.

METHODS

We report two cases of DIP wherein the symptoms of parkinsonism persisted more than 6-months from withdrawal of the dopamine receptor blocking agent (DRBA) and the results of their ioflupane iodine-123 (DaT) single-photon emission computed tomography (SPECT) scan. DaT scan is a newly approved radiopharmaceutical in the United States indicated for striatal dopamine transporter visualization to assist in the evaluation of adult patients with suspected parkinsonian syndromes.

RESULTS

The first case is a patient who developed parkinsonism from risperidone, while the second case developed parkinsonism from metoclopramide. In both cases, parkinsonism persisted 6 months after discontinuation of the DRBA, therefore DaT scan was obtained, showing normal striatal dopamine transporter uptake. Nine months after the discontinuation of the DRBA, parkinsonism was significantly improved in both patients but not completely resolved.

CONCLUSION

Our two cases illustrate the possibility of persistent parkinsonism beyond 6-9 months from the time of neuroleptic withdrawal without evidence of presynaptic dopaminergic neuronal loss that would be suggestive of conversion to PD. We recommend that the official recommendation of the minimum time of neuroleptic withdrawal be modified to at least 1 year before entertaining the diagnosis of PD conversion in patients with exposure to DRBAs.

Abstract IA24: Drugging the undruggable: Small-molecule inhibition of Ras oncoprotein

Ras is a nucleotide-dependent switch that converts from an inactive GDP-bound state to an active GTP-bound state when activated by guanine nucleotide exchange factors, such as SOS. Active RasGTP then binds to and activates downstream signaling effectors. Ras is the most frequently mutated oncogene and hyperactive mutant Ras constitutively signals to effectors to promote cell survival, proliferation and metastasis. Thus, Ras oncoprotein has been considered by the cancer community to be one of the most important oncology drug targets. Despite the enormous interest and extensive exploratory efforts in industry and academia, small molecules that bind to Ras in a well-defined manner and exert inhibitory effects have not been uncovered to date. We report here the identification and characterization of small-molecule inhibitors of the Ras oncoprotein.

To explore a new means of directly targeting Ras, we used a fragment-based lead discovery approach via an NMR-based screen. Hits from the fragment screen were characterized for their interactions with Ras by NMR and X-ray crystallography and for their effects on Ras activation and signaling in reconstituted biochemical assays in vitro and in cellular assays in vivo. From the fragment-based screen, we identified a group of small molecules that each bind to a common site adjacent to the switch I/II regions in the Ras protein. X-ray crystallography studies of three compound-Ras complexes indicate that the binding site can be expanded upon ligand binding. Nucleotide exchange factors, notably SOS, are required to convert inactive RasGDP to active RasGTP. We determined that the compound-binding site is located at the interface of Ras and SOS. A subset of our Ras-binding molecules indeed inhibited SOS-mediated nucleotide exchange. Further mechanistic studies revealed that through steric hindrance the compounds block the formation of the Ras-SOS complex, a key intermediate of the exchange reaction. At the cellular level, our compounds inhibit the formation of active RasGTP and prevent Ras signaling to downstream effectors. To define the potential clinic utility of these compounds, we performed biological characterization of Ras-driven tumors and identified a subset of Ras mutant tumors that depend on nucleotide exchange factors for the activation of Ras, suggesting a specific profile for the use of exchange inhibitors.

We conclude that the compounds act as competitive inhibitors of nucleotide exchange to prevent the activation of Ras. The discovery of a binding pocket on Ras with functional significance represents a breakthrough finding that will offer a new direction for therapeutic intervention of Ras. Our findings provide new opportunities to target the “undruggable” Ras oncoprotein.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr IA24.

Effect of fenofibrate on microcirculation and wound healing in healthy and diabetic mice

Objective

Disturbances in wound healing in patients with hyperglycaemic blood sugar values are a common clinical problem. Recent studies identified PPARα-ligands as potential skin therapeutic agents. The aim of this study was to investigate the effects of oral fenofibrate treatment on dermal wound healing and micro-circulatory parameters in diabetic mice.

Methods

Dermal wounds were created in CD-1 mice. Mice were randomized into four treatment groups: diabetic mice treated (dbf) or not-treated with fenofibrate (dbnf). As controls served non-diabetic mice treated (ndf) or not-treated with fenofibrate (ndnf). At various points in time microcirculation was analyzed by intravital fluorescent microscopy to determine wound surface area, vessel diameter, plasma leakage, functional capillary density, and leukocyte/endothelium interaction.

Results

The dbf-mice showed a significantly increased diameter of the venules and the arterioles up to 3 days after wound creation compared to dbnf-mice. However, wound healing was not improved in dbf-compared to dbnf-mice. Surprisingly, all microcirculatory parameter (vessel diameter, plasma leakage and functional capillary density) were not deteriorated in dbnf-compared to ndnf-mice.

Conclusion

We confirm that high blood sugar values lead to a delayed wound healing, but this could not traced back to altered microcirculatory patterns. Furthermore, in dbf-mice an improved vasodilatatory function of small vessels could be detected, but with no substantial effect on wound healing. Further studies are needed to clarify, if topical application of fenofibrate might be beneficial.

Arrival time parametric imaging: a new ultrasound technique for quantifying perfusion of kidney grafts

PURPOSE

Evaluation of a new standardised ultrasound (US) technique for diagnosis of acute rejection of kidney grafts.

MATERIALS AND METHODS

Twenty-two kidney recipients underwent US examination following administration of 1.6 ml US contrast medium (USCM, SonoVue) 6 days after kidney transplantation. The examinations were performed with the Aplio US system (Toshiba). The difference in time to the first increase in signal intensity between the renal artery and the renal cortex was determined. Subsequently, the temporal course of contrast enhancement in the area of the renal artery following the first peak was recorded over 10 sec and depicted in colour using a Windows-based software. The resulting colour-time-images were evaluated by three readers who rated the images on an analogue scale from 1 (normal) to 5 (abnormal).

RESULTS

12 of the 22 patients had an uneventful clinical course. US demonstrated rapid inflow of the USCM into the renal cortex. The calculated time difference was 1.0 +/- 0.4 sec. The score assigned to the parametric images was 1.7 +/- 0.8. 8 of the 22 patients underwent biopsy and showed histologically proven rejection. The time difference in the rejection group was twice as high as in the normal group (2.2 +/- 0.7 sec, p < 0.05). The scores were in the abnormal range (3.7 +/- 1.6, p < 0.05). Two patients with perirenal haematoma also had high scores, without rejection.

CONCLUSIONS

Acute rejection and perirenal haematoma are associated with a delayed signal increase in the renal cortex. This information can be provided with a single image with standardised colour display of the temporal course of USCM inflow.

Persistent redistribution of poly-adenylated mRNAs correlates with translation arrest and cell death following global brain ischemia and reperfusion

Although persistent translation arrest correlates with the selective vulnerability of post-ischemic hippocampal cornu ammonis 1 (Ammon's horn) (CA1) neurons, the mechanism of persistent translation arrest is not fully understood. Using fluorescent in situ hybridization and immunofluorescence histochemistry, we studied colocalization of polyadenylated mRNAs [poly(A)] with the following mRNA binding factors: eukaryotic initiation factor (eIF) 4G (translation initiation factor), HuR (ARE-containing mRNA stabilizing protein), poly-adenylated mRNA binding protein (PABP), S6 (small ribosomal subunit marker), T cell internal antigen (TIA-1) (stress granule marker), and tristetraprolin (TTP) (processing body marker). We compared staining in vulnerable CA1 and resistant CA3 from 1 to 48 h reperfusion, following 10 min global ischemia in the rat. In both CA1 and CA3 neurons, cytoplasmic poly(A) mRNAs redistributed from a homogenous staining pattern seen in controls to granular structures we term mRNA granules. The mRNA granules abated after 16 h reperfusion in CA3, but persisted in CA1 neurons to 48 h reperfusion. Protein synthesis inhibition correlated precisely with the presence of the mRNA granules. In both CA1 and CA3, the mRNA granules colocalized with eIF4G and PABP, but not S6, TIA-1 or TTP, indicating that they were neither stress granules nor processing bodies. Colocalization of HuR in the mRNA granules correlated with translation of 70 kDa inducible heat shock protein, which occurred early in CA3 (8 h) and was delayed in CA1 (36 h). Thus, differential compartmentalization of mRNA away from the 40S subunit correlated with translation arrest in post-ischemic neurons, providing a concise mechanism of persistent translation arrest in post-ischemic CA1.

A xenogeneic PSMA DNA vaccine for patients (pts) with non-castrate metastatic (NCMPC) and castrate metastatic prostate cancer (CMPC)—A phase I trial of proof of principle

3073

Background: Prostate Specific Membrane Antigen (PSMA) represents a target for both primary and metastatic prostate cancer and an anti-angiogenic approach for other solid tumors. Antitumor effects in PC have been observed using autologous dendritic cells pulsed with PSMA peptides. This is a pilot phase I trial of vaccination with a DNA encoding PSMA in patients with PC. The objective was to determine the safety and immunogenicity of vaccination with the genes encoding for mouse and human PSMA in patients with recurrent disease. The hypothesis was that xenogeneic DNA encoding a xenogeneic homologous antigen was a more potent immunogen than self DNA. Methods: Thirty-six HLA-A0201+ pts with either NCMPC or CMPC were randomly assigned to vaccination with either xenogeneic (mouse) or human (self) PSMA DNA delivered i.m. via a high pressure delivery system at 100μg, 1,500μg or 4,000μg every 3 weeks for 3 immunizations. Those pts randomized initially to receive human PSMA DNA received 3 immunizations with mouse PSMA DNA at three week intervals. Sera and peripheral blood mononuclear cells were analyzed for humoral and T cell responses Results: Twenty-nine of 36 pts were evaluable having received all six vaccines. Nine remain active without disease progression or significant change in PSA logslope. One of 6 pts treated at the 4,000μg cohort has been followed by > 92 weeks; at the 1,500μg cohort 1 of 2 pt has been monitored for > 110 weeks; and 1 pt at the 100μg dose has remained on study for > 169 weeks. No high titer antibodies against PSMA were detected by ELISA or FACS against 3T3 fibroblasts transduced to express PSMA. Conclusions: The vaccine was safe at all dose levels without evidence of autoimmune reactivity. While antibodies against PSMA were not detected, studies are ongoing to examine T cell responsiveness. The majority of pts who remain on study were treated at 4,000μg dose level which appears to be the optimal dose. Supported by The Prostate Cancer Foundation and MSKCC Prostate Cancer SPORE

No significant financial relationships to disclose.

Convergence of stress granules and protein aggregates in hippocampal cornu ammonis 1 at later reperfusion following global brain ischemia

The delayed and selective vulnerability of post-ischemic hippocampal cornu ammonis (CA) 1 pyramidal neurons correlates with a lack of recovery of normal protein synthesis. Recent evidence implicates sequestration of translational machinery into protein aggregates and stress granules as factors underlying persistent translation arrest in CA1 neurons. However, the relationship between protein aggregates and stress granules during brain reperfusion is unknown. Here we investigated the colocalization of protein aggregates and stress granules using immunofluorescence microscopy and pair-wise double labeling for ubiquitin/T cell internal antigen (TIA-1), ubiquitin/small ribosomal subunit protein 6 (S6), and TIA-1/S6. We evaluated the rat dorsal hippocampus at 1, 2 or 3 days of reperfusion following a 10 min global brain ischemic insult. At 1 day of reperfusion, ubiquitin-containing aggregates (ubi-protein clusters) occurred in neurons but did not colocalize with stress granules. At 2 days' reperfusion, only in CA1, cytoplasmic protein aggregates colocalized with stress granules, and ubiquitin-containing inclusions accumulated in the nuclei of CA1 pyramidal neurons. Functionally, a convergence of stress granules and protein aggregates would be expected to sustain translation arrest and inhibit clearance of ubiquitinated proteins, both factors expected to contribute to CA1 pyramidal neuron vulnerability.

Anisotropic spin transport in (110) GaAs quantum wells

Mobile piezoelectric potentials are used to coherently transport electron spins in GaAs (110) quantum wells (QW) over distances exceeding 60 microm. We demonstrate that the dynamics of mobile spins under external magnetic fields depends on the direction of motion in the QW plane. This transport anisotropy is an intrinsic property of moving spins associated with the bulk inversion asymmetry of the underlying GaAs lattice.

[Pulmonary embolism and deep vein thrombosis in the inferior vena cava affected by a rare anomaly]

Persistent left-sided inferior vena cava (VCI) is a rare venous anomaly, its prevalence being estimated at 0.2-0.5%. Thrombotic occlusion of a VCI has been reported in only a few of these cases. We report the case of a 24-year old woman who suffered an acute thrombosis in a left-sided VCI and recurrent pulmonary embolism. After thrombectomy the course was uneventful. The diagnostic approach and the treatment strategy are discussed with reference to the literature.

Magnetic resonance imaging findings of basal cell adenoma in Curschmann-Steinert myotonic dystrophy

Myotonic dystrophy Curschmann Steinert is a common hereditary disorder that in some cases can be combined with cutaneous tumors, which is an association that is rarely described in the literature. We present the magnetic resonance imaging in the unusual combination of a patient with known myotonic dystrophy and recurrent basal cell tumor.

Lipom des Kleinhirnbrückenwinkels - eine Falldemonstration

BACKGROUND

Lipomas of the cerebellopontine angle are rare. Until today in the english literature only isolated cases are described. The most frequent symptoms are: hearing loss (62,2 %), vertigo (43,3 %) and tinnitus (42,2 %). With the help of MRI intracranial lipomas can be diagnosed almost certainly.

PATIENT

A 26 year old patient presented himself to our outpatient departement with recurrent vertigo and tinnitus since two months. Electronystagmography and caloric testing showed a unilateral weakness of the right vestibular organ. Audiometric examination revealed a Normacusis on the right side. BERA resulted in borderline prolonged interpeaklatency on the right side, wave I-V. MRI showed a ca. 5x8x11 mm Lipoma of the right cerebellopontine angel which surrounded the vestibulocochlear nerve. In contrast to schwannomas which are often described in this area the lesion did not enhance contrast medium. On the native T1 sequence the tumor was hyperintense and fat-supression images confirmed the tumor to be fat in origin. Because of the minor symptoms and the small size of the tumor we recommended a BERA after six months and an MRI every year.

CONCLUSION

The therapeutic options of a lipoma of the cerebellopontine angel depend on the clinical symptoms and a radiologic confirmed progression of size. Because of the received data until today an operative therapy is only indicated when symptoms clinically can not be treated or the leason seems to be a well differentiated liposarcoma.

Eine neue Methode zur standardisierten Diagnostik nach Nierentransplantation

Ultrasound (US) imaging is an important diagnostic tool following renal transplantation. Unfortunately, due to the heterogeneity of the recipients and their multimorbidity, imaging procedures in the early phase after kidney transplantation are difficult and of limited use. We performed a study to evaluate the use of a contrast enhancer for US examination as a standardized method in the follow-up of kidney transplant recipients.The study included 40 recipients: 32 were examined on the 5th to 7th day following transplantation and 8 patients at the time when clinically suspicious findings occurred (acute rejection, tumor, acute tubular necrosis). Following the intravenous application of the contrast medium, pictures were taken during the arterial and parenchymatous phase and compared with conventional B-mode and power Doppler pictures of the same visual plane. Three examiners assessed different parameters of the transplant organ (max. vascularized area, suspected hematomas, tumors, rejection, acute tubular necrosis). Findings were confirmed by histological results of a biopsy if rejection, tumor, or acute tubular necrosis were suspected. Application of ultrasound contrast medium significantly increased visualization of the vascularized kidney area. Also, US findings in the follow-up after acute rejection therapy corresponded with the clinical course; 19 hematomas could be detected with contrast medium compared to only 9 without. With contrast medium a perfusion deficit was detectable in three patients compared to one patient with power Doppler US. Also, US contrast medium helped to detect tumor vascularization in two patients in whom conventional sonography suspected no abnormality. Ultrasound contrast medium enhancement is a reproducible, reliable, and easy to apply method which is superior to conventional sonography in the follow-up after kidney transplantation. This method is also helpful to detect and control acute rejections and to better visualize hematomas, deficits of perfusion, and tumors.

Coarse and reliable geometric alignment for protein docking

We present an efficient algorithm for generating a small set of coarse alignments between interacting proteins using meaningful features on their surfaces. The proteins are treated as rigid bodies, but the results are more generally useful as the produced configurations can serve as input to local improvement algorithms that allow for protein flexibility. We apply our algorithm to a diverse set of protein complexes from the Protein Data Bank, demonstrating the effectivity of our algorithm, both for bound and for unbound protein docking problems.

Transarterielle Embolisation bei Uterus myomatosus: klinische Erfolgsrate und kernspintomographische Ergebnisse

PURPOSE

To analyze the clinical success rate and the findings of magnetic resonance imaging (MRI) after uterine artery embolization of symptomatic leiomyomas (fibroids) of the uterus.

MATERIALS AND METHODS

This is a prospective single-center case study of 80 consecutively treated patients, followed for 3 - 6 months (group I), 7 - 12 months, (group II), and 13 - 25 months (group III). MRI was used to determine the uterine volume and size of the dominant leiomyoma. Symptoms and causes requiring repeat interventions were analyzed.

RESULTS

Significant (p < 0.01) volume reduction of the uterus (median: 34.95 % confidence interval [CI]: 30.41 - 41.76 %) and dominant leiomyoma (median: 52.07 %, CI: 47.71 - 61.57 %) was found. The decrease in uterine volume (I-III: 22.68 %, 33.56 %, 47.93 %) and dominant leiomyoma volume (I-III: 41.86 %, 62.16 %, 73.96 %) progressed with the follow-up time. Bleeding resolved significantly (p < 0.0001) in all three follow-up groups (groups I-III: 92.86 %, 95.23 %, 96.67 %). Furthermore, urinary frequency (groups I-III: 70 %, 75 %, 82.35 %) and sensation of pelvic pressure (groups I-III: 42.86 %, 60 %, 93.75 %) improved, which was statistically significant in group III (p < 0.01). The number of leiomyomas correlated (p < 0.05) with improvement of the bleeding and the pelvic pressure. Repeat therapy was necessary for complications in four patients (5 %) and for therapeutic failure in three patients (3.8 %). Permanent amenorrhea was observed in four patients (5 %) of age 45 years or older.

CONCLUSION

Uterine artery embolization of uterine leiomyomas has a high clinical success rate with an acceptable incidence of complications and repeat interventions.

Remote hot spots mediate protein substrate recognition for the Cdc25 phosphatase

Cdc25B is a phosphatase that catalyzes the dephosphorylation and activation of the cyclin-dependent kinases, thus driving cell cycle progression. We have identified two residues, R488 and Y497, located >20 A from the active site, that mediate protein substrate recognition without affecting activity toward small-molecule substrates. Injection of Cdc25B wild-type but not the R488L or Y497A variants induces germinal vesicle breakdown and cyclin-dependent kinase activation in Xenopus oocytes. The conditional knockout of the cdc25 homolog (mih1) in Saccharomyces cerevisiae can be complemented by the wild type but not by the hot spot variants, indicating that protein substrate recognition by the Cdc25 phosphatases is an essential and evolutionarily conserved feature.

Anomalous spin dephasing in (110) GaAs quantum wells: anisotropy and intersubband effects

A strong anisotropy of electron spin decoherence is observed in GaAs/(AlGa)As quantum wells grown on a (110) oriented substrate. The spin lifetime of spins perpendicular to the growth direction is about one order of magnitude shorter compared to spins along [110]. The spin lifetimes of both spin orientations decrease monotonically above temperatures of 80 and 120 K, respectively. The decrease is very surprising for spins along the [110] direction and cannot be explained by the usual Dyakonov-Perel dephasing mechanism. A novel spin dephasing mechanism is put forward that is based on scattering of electrons between different quantum well subbands.

Unusual enhancement pattern of liver lesions in hepatosplenic candidiasis

PURPOSE

To describe an unusual enhancement pattern of hepatosplenic candidiasis (HSC) liver lesions in biphasic spiral liver computed tomography (CT).

MATERIAL AND METHODS

Twenty-one patients with suspected HSC were scanned with a biphasic liver CT perfusion protocol. The liver lesions detected were assessed for their morphology and enhancement pattern during both perfusion phases. A liver biopsy was performed in 11/21 patients.

RESULTS

The majority of hepatic lesions in 15/21 patients showed the well-known abscess-like pattern. In 6/21 patients an uncommon central contrast enhancement with a peripheral double ring was detected in the arterial phase. In some cases the lesions showed decreased diameter or even seemed to disappear completely in the portalvenous phase.

CONCLUSIONS

CT in the arterial phase showed an unusual enhancement pattern of liver lesions in HSC. Scanning only in the portalvenous phase implies possible pitfalls, because lesions may be overlooked or undersized. Therefore, biphasic liver CT is considered essential in the diagnosis and follow-up of HSC in clinical practice.

Cdc25 Phosphatases and Cancer

The Cdc25 phosphatases function as key regulators of the cell cycle during normal eukaryotic cell division and as mediators of the checkpoint response in cells with DNA damage. The role of Cdc25s in cancer has become increasingly evident in recent years. More than 20 studies of patient samples from diverse cancers show significant overexpression of Cdc25 with frequent correlation to clinical outcome. Recent screening and design efforts have yielded novel classes of inhibitors that show specificity for the Cdc25s over other phosphatases and cause cell cycle arrest in vivo. Herein we provide a single source for those interested in the cellular functions of Cdc25 in cell cycle progression, its role in the progress of cancer and survival of cancer patients, and recent efforts in the design of specific inhibitors.

Early Postoperative Ultrasound of Kidney Transplants: Evaluation of Contrast Medium Dynamics Using Time-intensity Curves

OBJECTIVE

To evaluate kidney recipients in the early posttransplant phase by semiquantitative analysis of the arterial arrival of ultrasound (US) contrast medium using time-intensity curves.

PATIENTS AND METHODS

Twenty-two kidney recipients underwent US examination after intravenous bolus administration of 2.4 ml of US contrast medium (SonoVue, Bracco Altana) 5 to 7 days after transplantation. The examinations were performed with the Aplio US system (Toshiba) and a 3.5-MHz wideband transducer using contrast harmonic imaging at a low mechanical index of 0.1. Arterial arrival was documented digitally over 60 sec (image repetition rate: 10 images per sec) for subsequent evaluation of contrast medium kinetics in the main renal artery, interlobar artery, subcapsular area, and renal vein using the system's integrated time-intensity curve (TIC) software. The increase, decrease, and percentage enhancement factor were calculated from the curves. Four patients were excluded from analysis because of perirenal hematoma (n = 3) or a polar perfusion loss demonstrated by power Doppler (n = 1).

RESULTS

Twelve of the remaining 18 patients assigned to the nonrejection group showed an uneventful clinical course. These had uniform TICs with an early and steep increase of similar magnitude in the main renal artery (11.7 +/- 4.5 intensity units/sec), interlobar artery (8.7 +/- 4.6 intensity units/sec), and subcapsular area (8.3 +/- 3.7 intensity units/sec) followed by a washout and subsequent plateau phase. Six patients showed histologically proven acute rejection on day 5 or 6 after transplantation (rejection group). This group had a delayed (time to peak in the subcapsular area: 32.9 +/- 8.3 sec in the rejection group versus 20.9 +/- 4.7 sec in the nonrejection group, p < 0.05) and smaller subcapsular percentage increase (41.2 +/- 21.9 % versus 114.4 +/- 59.8 %, p < 0.05). In the rejection group the subcapsular area (3.8 +/- 2.3 intensity units/sec) showed a less pronounced increase than the main renal artery (7.9 +/- 5.9 intensity units/sec) and interlobar artery (8.7 +/- 3.8 intensity units/sec). The RI in the rejection group was in the normal range at the time of contrast-enhanced US (day 5: 0.78 +/- 0.06) and increased to abnormal levels in the further course (day 7: 0.94 +/- 0.09).

CONCLUSIONS

Quantitative determination of arterial arrival of an US contrast medium in the early phase after kidney transplantation is possible. This new US procedure might identify acute rejection earlier than conventional techniques.