Showing papers by "Free University of Berlin published in 1997"

Identification of tissue transglutaminase as the autoantigen of celiac disease

Abstract: Celiac disease is characterized by small intestinal damage with loss of absorptive villi and hyperplasia of the crypts, typically leading to malabsorption. In addition to nutrient deficiencies, prolonged celiac disease is associated with an increased risk for malignancy, especially intestinal T-cell lymphoma. Celiac disease is precipitated by ingestion of the protein gliadin, a component of wheat gluten, and usually resolves on its withdrawal. Gliadin initiates mucosal damage which involves an immunological process in individuals with a genetic predisposition. However, the mechanism responsible for the small intestinal damage characteristic of celiac disease is still under debate. Small intestinal biopsy with the demonstration of a flat mucosa which is reversed on a gluten-free diet is considered the main approach for diagnosis of classical celiac disease. In addition, IgA antibodies against gliadin and endomysium, a structure of the smooth muscle connective tissue, are valuable tools for the detection of patients with celiac disease and for therapy control. Incidence rates of childhood celiac disease range from 1:300 in Western Ireland to 1:4700 in other European countries, and subclinical cases detected by serological screening revealed prevalences of 3.3 and 4 per 1000 in Italy and the USA, respectively. IgA antibodies to endomysium are particularly specific indicators of celiac disease, suggesting that this structure contains one or more target autoantigens that play a role in the pathogenesis of the disease. However, the identification of the endomysial autoantigen(s) has remained elusive. We identified tissue transglutaminase as the unknown endomysial autoantigen. Interestingly, gliadin is a preferred substrate for this enzyme, giving rise to novel antigenic epitopes.

A simple min-cut algorithm

Abstract: We present an algorithm for finding the minimum cut of an undirected edge-weighted graph. It is simple in every respect. It has a short and compact description, is easy to implement, and has a surprisingly simple proof of correctness. Its runtime matches that of the fastest algorithm known. The runtime analysis is straightforward. In contrast to nearly all approaches so far, the algorithm uses no flow techniques. Roughly speaking, the algorithm consists of about |V| nearly identical phases each of which is a maximum adjacency search.

The assessment of optimistic self-beliefs : Comparison of the German, Spanish, and Chinese versions of the general self-efficacy scale

Abstract: L'auto-efficacite generale est mesuree grâce a une courte echelle composee de dix items. Son usage est tres repandu et elle a ete adaptee a plusieurs cultures. Cet article compare des versions qui ont ete proposees a des etudiants: 430 Allemands, 952 Costariciens et 293 Chinois. lies validites internes sont respectivement de.84,.81 et.91. L'unidimensionnalite de l'echelle est reapparue dans tous les echantillons. L'equivalence items-modele interlinguistique ne fut que moderement approuve par des analyses factorielles de confirmation. On a trouve des differences au niveau des moyennes des scores totaux entre les langues. De plus, une interaction entre sexe et langue s'est manifestee. Des correlations avec la depression, l'anxiete' et l'optimisme ont fourni des elements complementaires en faveur de la validite de construction. General self-efficacy is measured by a widely used parsimonious ten-item scale that was developed for use in several cultures. The present paper compares the verions that were examined in samples of 430 German, 959 Costa Rican, and 293 Chinese university students. The internal consistencies were.84,.81, and.91, respectively. The unidimensional nature of the scale was replicated in all samples. Multilingual item-pattern equivalence was only moderately supported by confirmatory factor analyses. Mean differences of sum scores between languages were found. Moreover, an interaction between gender and language emerged. Correlations with depression, anxiety, and optimism provided some further evidence for construct validity.

Signal characteristics of G protein-transactivated EGF receptor.

Abstract: The epidermal growth factor receptor (EGFR) tyrosine kinase recently was identified as providing a link to mitogen-activated protein kinase (MAPK) in response to G protein-coupled receptor (GPCR) agonists in Rat-1 fibroblasts. This cross-talk pathway is also established in other cell types such as HaCaT keratinocytes, primary mouse astrocytes and COS-7 cells. Transient expression of either Gq- or Gi-coupled receptors in COS-7 cells allowed GPCR agonist-induced EGFR transactivation, and lysophosphatidic acid (LPA)-generated signals involved the docking protein Gab1. The increase in SHC tyrosine phosphorylation and MAPK stimulation through both Gq- and Gi-coupled receptors was reduced strongly upon selective inhibition of EGFR function. Inhibition of phosphoinositide 3-kinase did not affect GPCR-induced stimulation of EGFR tyrosine phosphorylation, but inhibited MAPK stimulation, upon treatment with both GPCR agonists and low doses of EGF. Furthermore, the Src tyrosine kinase inhibitor PP1 strongly interfered with LPA- and EGF-induced tyrosine phosphorylation and MAPK activation downstream of EGFR. Our results demonstrate an essential role for EGFR function in signaling through both Gq- and Gi-coupled receptors and provide novel insights into signal transmission downstream of EGFR for efficient activation of the Ras/MAPK pathway.

Epstein‐Barr virus‐associated Hodgkin's disease: Epidemiologic characteristics in international data

Abstract: Hodgkin's disease (HD) has long been suspected to have an infectious precursor, and indirect evidence has implicated Epstein-Barr virus (EBV), a ubiquitous herpesvirus, as a causal agent. Recent molecular studies using EBER in situ hybridization or latency membrane protein-I (LMP-I) immunohistochemistry have identified EBV latent infection in up to 50% of HD tumors. However, the epidemiologic features of these cases have not been examined in detail. To explore the epidemiology of EBV-positive HD so as to understand the role of EBV in HD etiology more clearly, this project accumulated patient data from 14 studies that had applied these EBV assays to HD tumors. With information on age at diagnosis, sex, ethnicity, histologic subtype, country of residence, clinical stage and EBV tumor status from 1,546 HD patients, we examined risk for EBV-positive disease using logistic regression. Forty percent of subjects had EBV-positive tumors, and EBV prevalence varied significantly across groups defined by the study variables. Odds ratios (OR) for EBV-associated HD were significantly elevated for Hispanics vs. whites (OR = 4.1), mixed cellularity vs. nodular sclerosis histologic subtypes (OR = 7.3, 13.4, 4.9 for ages 0-14, 15-49, 50+ years), children from economically less-developed vs. more-developed regions and young adult males vs. females (OR = 2.5). These findings suggest that age, sex, ethnicity and the physiologic effects of poverty may represent biologic modifiers of the EBV association and confirm that this association is strongly but variably linked to histologic subtype. The data augment biologic evidence that EBV is actively involved in HD pathogenesis in some cases but describe epidemiologic complexity in this process.

Representations of odours and odour mixtures visualized in the honeybee brain

Abstract: Most animals depend on the identification of odours to locate food or to find mating partners. To accomplish this, the olfactory system must recognize relative concentrations of a large number of substances by analysing complex patterns of chemoreceptor activations1,2, but how these patterns are represented in the brain is not well understood. Previous studies indicated that odours evoke specific patterns of activity in olfactory sensory centres3–7 and led to the hypothesis that single glomeruli in the olfactory bulb of mammals respond to particular receptor types8–10. We made optical recordings in vivo in the honeybee brain to investigate neuronal population responses to odorants delivered naturally to the animal. We report here that odours evoked specific spatio–temporal excitation patterns in the antennal lobe, the structural and functional analogue of the olfactory bulb11. Specific ensembles of active glomeruli represent odours in a combinatorial manner. A comparison between different individuals shows remarkable similarities for a pheromone component, but not for general flower odours. Mixtures evoked patterns that were combinations of the single odorant responses. These combinations were not fully additive, however, indicating inhibitory effects on single glomeruli. Such interactions could be crucial for the formation of singular codes for complex odour blends.

A new microsurgical technique for minimally invasive anterior lumbar interbody fusion

Abstract: Study design A series of patients were prospectively studied to determine the morbidity and possible complications of minimally invasive anterior lumbar interbody fusion by two new microsurgical approaches (retroperitoneal for segments L2-L3, L3-L4, and L4-L5, and transperitoneal for L5-S1). Objectives To investigate the feasibility of performing an anterior lumbar interbody fusion through a 4-cm skin incision and a standardized muscle-splitting approach. Summary of background data The utility of anterior lumbar interbody fusion with or without posterior instrumentation for the treatment of various degenerative or postoperative lesions associated with low back pain is still a matter of debate. Regardless of the indications for surgery, use of the anterior approach in the lumbar spine is known to be associated with considerable surgical trauma, a high postoperative morbidity, and, occasionally, unacceptably high complication rates. Laparoscopic anterior interbody fusion of L5-S1 to eliminate some of these problems has been recently described. However, a minimally invasive surgical concept that covers all lumbar segments from L2 to S1 has not been described before now. Methods A standardized, microsurgical retroperitoneal approach to levels L2-L3, L3-L4, and L4-L5 and a microsurgical transperitoneal approach through a "minilaparotomy" to L5-S1 are described. The first 25 patients (retroperitoneal, n = 20; transperitoneal, n = 5) treated with these methods are evaluated with respect to intraoperative data such as blood loss, operating time, intraoperative and postoperative complications, as well as preliminary fusion results. Results There were no general or technique-related complications in the first series of 25 patients. Postoperative morbidity was low in all patients, with negligible wound pain. Average blood loss was 67.8 ml for the retroperitoneal technique and 168 ml for the transperitoneal approach. No blood transfusion was necessary. All patients showed solid bony fusion. Conclusions The microsurgical approaches described in this article are atraumatic techniques to reach the lumbar spinal levels L2-L3, L3-L4, L4-L5, and L5-S1. They represent microsurgical modifications of the surgical approaches well known to the spine surgeon. They can be learned in a step-by-step fashion, starting with a conventional skin incision and, once the surgeon is familiar with the instruments, moving on to the microsurgical technique. The approaches are not restricted to the type of fusion (iliac crest autograft) presented in this series.

CTLA4 alanine-17 confers genetic susceptibility to Graves' disease and to type 1 diabetes mellitus.

Abstract: The genetic susceptibility to Graves' disease and type 1 (insulin-dependent) diabetes mellitus is conferred by genes in the human leukocyte antigen region on the short arm of chromosome 6, but several other genes are presumed to determine disease susceptibility. Among those candidate genes is the cytotoxic T lymphocyte antigen 4 (CTLA4) located on chromosome 2q33 in man. We investigated the distribution of the CTLA4 exon 1 polymorphism (49 A/G) in Graves' disease and IDDM. This dimorphism at codon 17 results in an amino acid exchange (Thr/Ala) in the leader peptide of the expressed protein and was analyzed by PCR, single strand conformation polymorphism, and restriction fragment length polymorphism analysis in 305 patients with Graves' disease, 293 patients with IDDM, and 325 controls. Patients with Graves' disease had significantly more Ala alleles than controls, both as homozygotes (21% vs. 13%) and as heterozygotes (53% vs. 46%), and less Thr as homozygotes (26% vs. 42%; P < 2 x 10(-4). The phenotypic frequency of Ala-positive patients (73%) was significantly higher than of controls (58%; P = 10(-4); relative risk = 2). Patients with IDDM also had significantly more Ala alleles as homozygotes (19%) or heterozygotes (50%; P = 0.01). In conclusion, an alanine at codon 17 of CTLA4 is associated with genetic susceptibility to Graves' disease as well as to IDDM.

Basic Steps of Lateral Manipulation of Single Atoms and Diatomic Clusters with a Scanning Tunneling Microscope Tip

Abstract: Detailed tip height measurements during manipulation of single atoms, molecules, and dimers on a Cu(211) surface reveal different manipulation modes depending on tunneling parameters. Both attractive (Cu, Pb, Pb dimers) and repulsive manipulation (CO) are identified. Using attractive forces, discontinuous hopping of Cu and Pb atoms from one adsorption site to the next can be induced (``pulling''). Pb dimers can be pulled with repeated single, double, and triple hops. Pb atoms can also be ``slid'' continuously. The occurrence of different movement patterns is shown to be a sensitive probe for surface defects.

Survival of Acinetobacter baumannii on dry surfaces.

Abstract: Acinetobacter spp. have frequently been reported to be the causative agents of hospital outbreaks. The circumstances of some outbreaks demonstrated the long survival of Acinetobacter in a dry, inanimate environment. In laboratory experiments, we compared the abilities of five Acinetobacter baumannii strains, three Acinetobacter sp. strains from the American Type Culture Collection (ATCC), one Escherichia coli ATCC strain, and one Enterococcus faecium ATCC strain to survive under dry conditions. Bacterial solutions of the 10 strains were inoculated onto four different material samples (ceramic, polyvinyl chloride, rubber, and stainless steel) and stored under defined conditions. We investigated the bacterial counts of the material samples immediately after inoculation, after drying, and after 4 h, 1 day, and 1, 2, 4, 8, and 16 weeks of storage. A statistical model was used to distribute the 40 resulting curves among four types of survival curves. The type of survival curve was significantly associated with the bacterial strain but not with the material. The ability of the A. baumannii strains to survive under dry conditions varied greatly and correlated well with the source of the strain. Strains isolated from dry sources survived better than those isolated from wet sources. An outbreak strain that had caused hospital-acquired respiratory tract infections survived better than the strains from wet sources, but not as well as strains from dry sources. Resistance to dry conditions may promote the transmissibility of a strain, but it is not sufficient to make a strain an epidemic one. However, in the case of an outbreak, sources of Acinetobacter must be expected in the dry environment.

Randomized Distributed Edge Coloring via an Extension of the Chernoff--Hoeffding Bounds

Abstract: Certain types of routing, scheduling, and resource-allocation problems in a distributed setting can be modeled as edge-coloring problems We present fast and simple randomized algorithms for edge coloring a graph in the synchronous distributed point-to-point model of computation Our algorithms compute an edge coloring of a graph $G$ with $n$ nodes and maximum degree $\Delta$ with at most $16 \Delta + O(\log^{1+ \delta} n)$ colors with high probability (arbitrarily close to 1) for any fixed $\delta > 0$; they run in polylogarithmic time The upper bound on the number of colors improves upon the $(2 \Delta - 1)$-coloring achievable by a simple reduction to vertex coloring To analyze the performance of our algorithms, we introduce new techniques for proving upper bounds on the tail probabilities of certain random variables The Chernoff--Hoeffding bounds are fundamental tools that are used very frequently in estimating tail probabilities However, they assume stochastic independence among certain random variables, which may not always hold Our results extend the Chernoff--Hoeffding bounds to certain types of random variables which are not stochastically independent We believe that these results are of independent interest and merit further study

Interleukin-15 protects from lethal apoptosis in vivo.

Abstract: Interleukin-15 shares many biological activities with IL-2 and signals through the IL-2 receptor β and γ chains1–3. However, IL-15 and IL-2 differ in their controls of expression and secretion, their range of target cells and their functional activities3–7. These dissimilarities may include differential effects on apoptosis. For example, IL-2 induces or inhibits T-cell apoptosis in vitro, depending on T-cell activation8, whereas IL-15 inhibits cytokine deprivation-induced apoptosis in activated T cells9. Studying whether and how IL-15 modulates distinct apoptosis pathways10–12, we show here that apoptosis induced by anti-Fas, anti-CD3, dexamethasone, and/or anti-IgM in activated human T and B cells in vitro is inhibited by IL-15 in a manner dependent on RNA synthesis. In vivo, anti-Fas-induced lethal multisystem apoptosis in mice is suppressed by a novel IL-15–lgG2b fusion protein. Only IL-15, but not IL-2, completely protected from lethal hepatic failure. Thus, IL-15 is a potent, general inhibitor of apoptosis in vitro and in vivo with intriguing therapeutic potential.

Functional and structural complexity of signal transduction via g-protein-coupled receptors

Abstract: A prerequisite for the maintenance of homeostasis in a living organism is finetuned communication between different cells. The majority of extracellular signaling molecules, such as hormones and neurotransmitters, interact with a threeprotein transmembrane signaling system consisting of a receptor, a G protein, and an effector. These single components interact sequentially and reversibly. Considering that hundreds of G-protein-coupled receptors interact with a limited repertoire of G proteins, the question of coupling specificity is worth considering. G-protein-mediated signal transduction is a complex signaling network with diverging and converging transduction steps at each coupling interface. The recent realization that classical signaling pathways are intimately intertwined with growth-factor‐signaling cascades adds another level of complexity. Elaborate studies have significantly enhanced our knowledge of the functional anatomy of G-protein-coupled receptors, and the concept has emerged that receptor function can be modulated with high specificity by coexpressed receptor fragments. These results may have significant clinical impact in the future.

Nonequilibrium magnetization dynamics of nickel

Abstract: Ultrafast magnetization dynamics of nickel has been studied for different degrees of electronic excitation, using pump-probe second-harmonic generation (SHG) with 150 fs, 800 nm laser pulses of various fluences. Information about the electronic and magnetic response to laser irradiation is obtained from sums and differences of the SHG intensity for opposite magnetization directions. The classical M(T) curve can be reproduced for delay times longer than the electron thermalization time of about $280$ fs, even when electrons and lattice have not reached thermal equilibrium. Further we show that the transient magnetization reaches its minimum $\ensuremath{\approx}50$ fs before electron thermalization is completed.

Measuring the quality of life of severely mentally ill people using the Lancashire Quality of Life Profile

Abstract: Quality of life (QOL) has become an important outcome measure for many disorders, including mental illness. The Lancashire Quality of Life Profile (LQOLP) was developed for use in operational contexts, and has been translated into several languages. It is in use in several European and North American community psychiatric services. The present paper addresses the questions: how easy is it to use?; how reliable is it?; do the results of the LQOLP vary by setting in a meaningful way?; how do the results co-vary with measures of clinical symptoms and social functioning?; how well does it measure change?; is it clinically useful? While most of the answers to these questions are favourable, there is a need for further research and development of the profile, in particular with reference to the consequences of the use of the profile as a routine monitoring instrument and the most appropriate form of statistical analysis in longitudinal data-sets.

Origin of nodular lymphocyte-predominant Hodgkin's disease from a clonal expansion of highly mutated germinal-center B cells

Abstract: Background The atypical cells of nodular lymphocyte-predominant Hodgkin's disease, designated lymphocytic and histiocytic (L&H) cells, have a B-cell phenotype. To clarify the clonality of these cells, we studied rearranged immunoglobulin genes for the variable region of the heavy chain (V H genes) in individual L&H cells from 11 patients with nodular lymphocyte-predominant Hodgkin's disease. We also studied the expression of immunoglobulin light chains by those cells in six of the same patients. Methods Single CD20+ L&H cells were isolated from frozen sections by a technique of micromanipulation. The rearranged V H genes of these cells were amplified by the polymerase chain reaction (PCR), sequenced, and compared with germ-line V H genes. Immunoglobulin light-chain messenger RNA (mRNA) was detected by in situ hybridization. Results Of 615 L&H cells isolated from all the frozen sections, 160 yielded PCR products. In each of the 11 patients, the L&H cells that could be evaluated had identically rearranged V...

Haplotypes of angiotensinogen in essential hypertension.

Abstract: Summary The M235T polymorphism of the angiotensinogen gene (AGT) has been associated with essential and pregnancy-induced hypertension. Generation of haplotypes can help to resolve whether the T235 allele itself predisposes to the development of hypertension or acts as a marker of an unknown causal molecular variant. We identified 10 dial-lelic polymorphisms at the AGT locus and genotyped both a series of 477 probands of hypertensive families and 364 controls, all French Caucasians, as well as a series of 92 hypertensives and 122 controls from Japan. Despite a large ethnic difference in gene frequency, a significant association of T235 with hypertension was observed both in Caucasians (.46 vs.38, P = .004) and in Japanese (.91 vs. .76, P = .002). In both groups, the G-←A substitution located at position-6 upstream of the initial transcription site occurred at the same frequency and in complete linkage disequilibrium with the T235 allele. No other polymorphism was found to be consistently associated with hypertension. Five informative haplotypes subdividing the T235 allele were generated. Whereas two of them were associated with hypertension in Caucasians, none of these two haplotypes (H3 and H4) reached statistical significance in Japanese. The analysis of the AGT-GT repeat revealed marked linkage disequilibriums between each of the diallelic polymorphisms and some (GT), alleles, with similar patterns in the two populations. The strong disequilibrium between M235 and (GT) 16 explained the increased frequency of that particular allele in French controls compared with hypertensives (.42 vs.36, P

Current Use and Future Potential Role of Retinoids in Dermatology

Abstract: Since their introduction 15 years ago, retinoids have been increasingly used for topical and systemic treatment of psoriasis and other hyperkeratotic and parakeratotic skin disorders, keratotic genodermatoses, severe acne and acne-related dermatoses, and also for therapy and/or chemoprevention of skin cancer and other neoplasia. Oxidative metabolites of vitamin A (retinol) are natural retinoids present at low levels in the peripheral blood. Synthetic retinoids are classified into 3 generations including nonaromatic, monoaromatic and polyaromatic compounds. They are detectable in plasma 30-60 minutes after systemic administration, and reach maximum concentrations 2 to 4 hours later. Elimination half-life is 10 to 20 hours for isotretinoin, 80 to 175 days for etretinate and 2 to 4 days for, trans-acitretin; the latter, however, partially converts into etretinate. Retinoid concentrations in skin are rather low in contrast to subcutaneous fat tissue. Intracellularly, retinoids interact with cytosolic proteins and specific nuclear receptors. Two classes of nuclear receptors have been suggested to mediate retinoid activity at the molecular level, RARs and RXRs. The expression of retinoid receptors is tissue specific; skin mainly espresses RAR gamma and RXR alpha. Retinoids affect epidermal cell growth and differentiation as well as sebaceous gland activity and exhibit immunomodulatory and anti-inflammatory properties. Current retinoid research targets the development of receptor-selective retinoids for tailoring and/or improving their therapeutic profile. Currently, tretinoin is used systemically for acute promyelocytic leukaemia, etretinate and acitretin for psoriasis and related disorders, as well as other disorders of keratinisation and isotretinoin for seborrhoea, severe acne, rosacea and acneiform dermatoses. Systemic retinoids are also applied for chemoprevention of epithelial skin cancer and cutaneous T cell lymphoma. The major adverse effect of retinoids is teratogenicity; all other adverse effects are dose-dependent and controllable. Contraception is, therefore, essential during retinoid treatment in women of child-bearing age. Clinical monitoring requires physical examination for adverse effects every 3 to 4 weeks and proper laboratory investigations, also including analysis of retinoid bioavailability in selected cases. Topical retinoids are rapidly developing at present and seem promising for the future; their clinical application includes acne, aging, photodamage, precanceroses, skin cancer and disorders of skin pigmentation. The development of receptor-specific retinoids for topical treatment of psoriasis and/or acne may lead to interesting new compounds based on our current concepts of retinoid function.

p300 is required for MyoD‐dependent cell cycle arrest and muscle‐specific gene transcription

Abstract: The nuclear phosphoprotein p300 is a new member of a family of 'co-activators' (which also includes the CREB binding protein CBP), that directly modulate transcription by interacting with components of the basal transcriptional machinery. Both p300 and CBP are targeted by the adenovirus E1A protein, and binding to p300 is required for E1A to inhibit terminal differentiation in both keratinocytes and myoblasts. Here we demonstrate that, in differentiating skeletal muscle cells, p300 physically interacts with the myogenic basic helix-loop-helix (bHLH) regulatory protein MyoD at its DNA binding sites. During muscle differentiation, MyoD plays a dual role: besides activating muscle-specific transcription, it induces permanent cell cycle arrest by up-regulating the cyclin-dependent kinase inhibitor p21. We show that p300 is involved in both these activities. Indeed, E1A mutants lacking the ability to bind p300 are greatly impaired in the repression of E-box-driven transcription, and p300 overexpression rescues the wild-type E1A-mediated repression. Moreover, p300 potentiates MyoD- and myogenin-dependent activation of transcription from E-box-containing reporter genes. We also provide evidence, obtained by microinjection of anti-p300 antibodies, that p300 is required for MyoD-dependent cell cycle arrest in either myogenic cells induced to differentiate or in MyoD-converted C3H10T1/2 fibroblasts, but is dispensable for maintenance of the postmitotic state of myotubes.

Epidemiological features of Adamantiades-Behçet's disease in Germany and in Europe

Abstract: The German Registry of Adamantiades-Behcet's disease was founded in 1990 in Berlin and it provides current data on the epidemiology, the clinical manifestations and the course of the disease in Germany on a continuous basis. A total of 218 patients, including 89 German and 100 Turkish patients, had been reported to the German Registry until October 1997. One hundred and ninety-six patients fulfilled the criteria of the Behcet's disease classification tree. The prevalence of the disease evaluated in Berlin-West was 1.68/100,000 in 1989 and had risen to 2.26/100,000 by 1994. The median age of onset was 25 years (range 5 to 66 years; German-Turks, ns). Juvenile disease was recorded in 6.9% of patients. The complete clinical picture according to the criteria of the International Study Group of Behcet's Disease developed in 15.5 months. The interval between onset of the disease and diagnosis was 35 months, which was significantly longer than the duration of the development of the complete clinical picture (p < 0.0001). The disease was diagnosed later in German (48.5 months) than in Turkish patients (25.5 months, p = 0.003). While German patients presented an equal male-to-female ratio, a male predominance was shown in Turkish patients (M:F 2.1:1, p = 0.022). Familial occurrence was detected in 2.0% of German and 15.9% of Turkish patients (p = 0.013). The frequencies of major clinical manifestations were: oral ulcers 99%, skin lesions 76%, genital ulcers 75%, ocular manifestations 59%, arthritis 59%, and positive pathergy test 52%. Clinical differences between German and Turkish patients were only found in the frequency of ocular lesions (48% vs. 66%, p = 0.025). Oral ulcers were with 72% the most common onset symptom of the disease followed by erythema nodosum (9%), uveitis (7%), arthritis (7%), genital ulcers (3%), superficial thrombophlebitis (2%) and papules/sterile pustules (2%). Uveitis and erythema nodosum as onset symptoms shortened the median interval to diagnosis to 1.5 and 15 months, respectively, while arthritis delayed diagnosis (43.5 months; p = 0.029). A severe course developed in 25% of the patients; irreversible retinal vasculitis to blindness in 15%, sterile meningoencephalitis in 8%, severe arthritis in 5%, hemoptysis in 2%, lethal outcome in 2% and bowel perforation in 1%. The relative risk of HLA-B5 positive German natives developing the disease. HLA-B5 was confirmed as a marker of severe prognosis. Cardiolipin autoantibodies were associated with cutaneous vasculitis and superficial thrombophlebitis was correlated with systemic vessel involvement.

The evolution of the Calvin cycle from prokaryotic to eukaryotic chromosomes: a case study of functional redundancy in ancient pathways through endosymbiosis

Abstract: The evolutionary histories of the 12 enzymes that catalyze the reactions of the Calvin cycle in higher-plant chloroplasts are summarized. They are shown to be encoded by a mixture of nuclear genes of cyanobacterial and proteobacterial origin. Moreover, where cytosolic isoforms of these enzymes are found they are almost invariably encoded by genes of clearly endosymbiont origin. We infer that endosymbiosis resulted in functional redundancy that was eliminated through differential gene loss, with intruding eubacterial genes repeatedly replacing pre-existing nuclear counterparts to which they were either functionally or structurally homologous. Our findings fail to support the `product-specificity corollary', which predicts re-targeting of nuclear-encoded gene products to the organelle from whose genome they originated. Rather it would appear that the enzymes of central carbohydrate metabolism have evolved novel targeting possibilities regardless of their origins. Our findings suggest a new hypothesis to explain organelle genome persistence, based on the testable idea that some organelle-encoded gene products might be toxic when present in the cytosol or other inappropriate cellular compartments.

Cytotoxicity of Solid Lipid Nanoparticles as a Function of the Lipid Matrix and the Surfactant

Abstract: Purpose. Assessment of the in vitro cytotoxicity of solid lipid nanoparticles (SLNs) as a function of lipid matrix (Dynasan 114, Compritol ATO 888), and stabilizing surfactant (poloxamers, Tween 80, soya lecithin, and sodium dodecyl sulphate). Comparison with other colloidal carriers should determine their potential use in the clinic.

Curcumin analogs with altered potencies against HIV-1 integrase as probes for biochemical mechanisms of drug action

Abstract: We have previously reported the inhibitory activity of curcumin against human immunodeficiency virus type one (HIV-1) integrase. In the present study, we have synthesized and tested analogs of curcumin to explore the structure-activity relationships and mechanism of action of this family of compounds in more detail. We found that two curcumin analogs, dicaffeoylmethane (6) and rosmarinic acid (9), inhibited both activities of integrase with IC50 values below 10 microM. We have previously demonstrated that lysine 136 may play a role in viral DNA binding. We demonstrated equivalent potencies of two curcumin analogs against both this integrase mutant and wild-type integrase, suggesting that the curcumin-binding site and the substrate-binding site may not overlap. Combining one curcumin analog with the recently described integrase inhibitor NSC 158393 resulted in integrase inhibition which was synergistic, reflective of drug-binding sites which may not overlap. We have also determined that these analogs can inhibit binding of the enzyme to the viral DNA but that this inhibition is independent of divalent metal ion. Furthermore, kinetic studies of these analogs suggest that they bind to the enzyme at a slow rate. These studies can provide mechanistic and structural information which may guide the future design of integrase inhibitors.

Expression of TRPC3 in Chinese Hamster Ovary Cells Results in Calcium-activated Cation Currents Not Related to Store Depletion

Abstract: TRPC3 (or Htrp3) is a human member of the trp family of Ca2+-permeable cation channels. Since expression of TRPC3 cDNA results in markedly enhanced Ca2+ influx in response to stimulation of membrane receptors linked to phospholipase C (Zhu, X., J. Meisheng, M. Peyton, G. Bouley, R. Hurst, E. Stefani, and L. Birnbaumer. 1996. Cell. 85:661–671), we tested whether TRPC3 might represent a Ca2+ entry pathway activated as a consequence of depletion of intracellular calcium stores. CHO cells expressing TRPC3 after intranuclear injection of cDNA coding for TRPC3 were identified by fluorescence from green fluorescent protein. Expression of TRPC3 produced cation currents with little selectivity for Ca2+ over Na+. These currents were constitutively active, not enhanced by depletion of calcium stores with inositol-1,4,5-trisphosphate or thapsigargin, and attenuated by strong intracellular Ca2+ buffering. Ionomycin led to profound increases of currents, but this effect was strictly dependent on the presence of extracellular Ca2+. Likewise, infusion of Ca2+ into cell through the patch pipette increased TRPC3 currents. Therefore, TRPC3 is stimulated by a Ca2+-dependent mechanism. Studies on TRPC3 in inside-out patches showed cation-selective channels with 60-pS conductance and short (<2 ms) mean open times. Application of ionomycin to cells increased channel activity in cell-attached patches. Increasing the Ca2+ concentration on the cytosolic side of inside-out patches (from 0 to 1 and 30 μM), however, failed to stimulate channel activity, even in the presence of calmodulin (0.2 μM). We conclude that TRPC3 codes for a Ca2+-permeable channel that supports Ca2+-induced Ca2+-entry but should not be considered store operated.