Structure of low density heparan sulfate proteoglycan isolated from a mouse tumor basement membrane

A large heparan sulfate proteoglycan of low buoyant density (p = 1.32 to 1.40 g/cm3 in 6 M-guanidine.HCl) was extracted from a tumor basement membrane with denaturing solvents and purified by chromatography and CsCl gradient centrifugation. Chemical, immunological, physical and electron microscopical analyses have demonstrated a high degree of purity and have allowed us to propose a structural model for this proteoglycan. It is composed of an 80 nm long protein core formed from a single polypeptide chain (Mr about 500,000) with intrachain disulfide bonds. This core is folded into a row of six globular domains of variable size as shown by electron microscopy after rotary shadowing and negative staining. A multidomain structure was confirmed by protease digestion experiments that allowed the isolation of a single heparan sulfate-containing peptide segment representing less than 5% of the total mass of the protein core. Electron microscopy has visualized generally three heparan sulfate chains in each molecule close to each other at one pole of the protein core. The molecular mass and length (100 to 170 nm) of the heparan sulfate chains were found to vary consistently between different preparations. The mass per length ratio (350 nm-1) indicated an extended conformation for the heparan sulfate side-chains. These structural features are distinctly different from those of the high density proteoglycan, suggesting that both forms of basement membrane heparan sulfate proteoglycan are genetically distinct and not derived from a common precursor.     

Test Based on Independent,but Non-identically Distributed Random Variables

The binomial test is applied for the problem of testing a hypothesis based on a sample of independent, but non-identically distributed random variables. The used basic idea is that each random variable indicates the presence of the hypothesis. Hence each random variable is transformed such that the binomial test can be used as a simple procedure.     

FISH in der Diagnostik hämatologischer Neoplasien

All hematological malignancies are characterized by considerable clinical heterogeneity. The diverse entities can be subdivided into a variety of prognosis-defining subtypes on the basis of cytogenetic aberrations and molecular mutations. To adapt the intensity of treatment to the patient’s individual risk profile, an exact classification of the subtypes on the basis of genetic markers is essential. Diverse fluorescent in situ hybridization (FISH) techniques thereby play a central role in interaction with classic chromosome banding analyses for clarifying findings of chromosome analyses, such as in the acute leukemias, or for classifying the diverse subtypes, as in the non-Hodgkin’s lymphomas. Depending on the disease, the clinical impact of FISH varies. It is used as the method of choice for genetic characterization (e.g., in multiple myeloma) or is used in combination with chromosome banding analysis. Furthermore, interphase FISH is essential when rapid confirmation of the diagnosis is needed, as in acute promyelocytic leukemia with the t(15;17)/PML-RARA rearrangement, for which therapy with all-trans retinoic acid (ATRA) should be immediately started.     

Pränatale Detektion fetaler chromosomaler Aberrationen im 1. und 2. Trimenon

Modern noninvasive methods of prenatal medicine, in particular first-trimester-screening, enable early risk evaluation of the most common forms of aneuploidy. With over 4000 certified gynecologists in Germany, this method nowadays represents the standard in prenatal risk evaluation. The importance of classic genetic sonography during the second trimester by detection of soft markers for aneuploidy has declined. However, detailed sonography during the second trimester remains the gold standard for the detection of congenital anomalies. Therefore, the specialist in prenatal medicine must be able to recognize soft markers during this examination in order to re-evaluate the maternal risk for aneuploidy.     

Renal collecting system growth and function depend upon embryonic γ1 laminin expression

In order to understand the functions of laminins in the renal collecting system, the Lamc1 gene was inactivated in the developing mouse ureteric bud (UB). Embryos bearing null alleles exhibited laminin deficiency prior to mesenchymal tubular induction and either failed to develop a UB with involution of the mesenchyme, or developed small kidneys with decreased proliferation and branching, delayed renal vesicle formation and postnatal emergence of a water transport deficit. Embryonic day 12.5 kidneys revealed an almost complete absence of basement membrane proteins and reduced levels of α6 integrin and FGF2. mRNA levels for fibroblast growth factor 2 (FGF2) and mediators of the GDNF/RET and WNT11 signaling pathway were also decreased. Furthermore, collecting duct cells derived from laminin-deficient kidneys and grown in collagen gels were found to proliferate and branch slowly. The laminin-deficient cells exhibited decreased activation of growth factor- and integrin-dependent pathways, whereas heparin lyase-treated and β1 integrin-null cells exhibited more selective decreases. Collectively, these data support a requirement of γ1 laminins for assembly of the collecting duct system basement membrane, in which immobilized ligands act as solid-phase agonists to promote branching morphogenesis, growth and water transport functions.     

Integrin α3β1 regulates kidney collecting duct development via TRAF6-dependent K63-linked polyubiquitination of Akt

The collecting system of the kidney develops from the ureteric bud (UB), which undergoes branching morphogenesis, a process regulated by multiple factors, including integrin–extracellular matrix interactions. The laminin (LM)-binding integrin α3β1 is crucial for this developmental program; however, the LM types and LM/integrin α3β1–dependent signaling pathways are poorly defined. We show that α3 chain–containing LMs promote normal UB branching morphogenesis and that LM-332 is a better substrate than LM-511 for stimulating integrin α3β1–dependent collecting duct cell functions. We demonstrate that integrin α3β1–mediated cell adhesion to LM-332 modulates Akt activation in the developing collecting system and that Akt activation is PI3K independent but requires decreased PTEN activity and K63-linked polyubiquitination. We identified the ubiquitin-modifying enzyme TRAF6 as an interactor with the integrin β1 subunit and regulator of integrin α3β1–dependent Akt activation. Finally, we established that the developmental defects of TRAF6- and integrin α3–null mouse kidneys are similar. Thus K63-linked polyubiquitination plays a previously unrecognized role in integrin α3β1–dependent cell signaling required for UB development and may represent a novel mechanism whereby integrins regulate signaling pathways.     

Beckwith-Wiedemann-Syndrom

The Beckwith-Wiedemann syndrome (BWS) is a pediatric overgrowth syndrome with a variable clinical appearance. The phenotype normalizes with age but the diagnosis of BWS is important as syndrome-specific complications may develop, in particular as a result of a 400-fold increased risk of patients developing certain tumor entities, predominantly nephroblastomas (Wilms’ tumors) and hepatoblastomas, within the first years of life. BWS displays a clinical overlap with other syndromes so that an unambiguous molecular diagnostic is required for risk assessment and appropriate therapy. At the molecular level BWS is associated with the chromosomal region 11p15.5, where two clusters with imprinted genes are located. In patients both genetic mutations and in most cases aberrant DNA methylation can be observed, which pathogenically affect the gene dosage of functionally available monoallelically expressed 11p15.5 genes. Currently only a very incomplete genotype-phenotype correlation exists for BWS. Current research projects provide insights in the molecular etiopathogenesis of the syndrome by identifying interacting partners which modify the epigenetic regulation of imprinted 11p15.5-genes.     

Die organogenetische und transitorische rolle der vitellophagen in der darmentwicklung von Galathea (Crustacea,Anomura)

The present study of the development of the different organs of the gut, the vitellophags (primary yolk cells) and the other cell-types concerned with the resorption of the yolk gives the first detailed analysis of an Anomuran development.

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Verzeichnis der Abkürzungen in den Abbilduugen A ₁ 1. Antenne - A ₂ 2. Antenne - Ab Abdomen - Au Auge - B Blastoderm - Bb Blastodermbildung - Bl Blutlakunensystem - Bm Blastomer (Furchungszelle) - Bp Blastoporus - BZ Blutzelle - Ca Cardiamagen - Cf Carapaxfalte - Cp Caudalpapille - DI Drüsenfilter (Magen) - zDk zentraler Dotterkörper - Do Dorsalorgan - pDp primare Dotterpyramide - tDp tertiare Dotterpyramide (Vitellophagenepithel) - DR Rest des intraembryonalen Dottersackes - ieDS intraembryonaler Dottersack - bDv blastodermale Dottervakuole - sDZ sekunddre Dotterzelle - tDZ tertiare Dotterzelle - sE sekunddre Epithelialisierung (der Vitellophagen) - Ec Ectoderm - Ed Enddarm - Eh Eihiille (Chorion) - Ep Entodermplatte - Et Entodermtrichter - Ex Extremitdt (bsw. Extremitätenanlage) - Fsp Furchungsspindel (Teilungsspindel) - H Herz - ID Innendotter - Im Immigration (des Mesentoderms) - In Invagination (des Mesentoderms) - Ke Kern - KL Kopflappen (optischer Lobus) - KM Kaumuskulatur - L Darmlumen - M Mitose - Ma Magen - Md Mitteldarm - dMd dorsaler Mitteldarmdivertikel (dorsaler Mitteldarmblindsack) - Me Mesoderm - McEn Mesentoderm - Mddr Mitteldarmdrüse - Ml Mandibel - Mp ₁ 1. Maxilliped (1. Kieferfuß) - Mp ₂ 2. Maxilliped (2. Kieferfuß) - Mp ₃ 3. Maxilliped (3. Kieferfuß) - Mu Muskulatur - M₁ 1. Maxille - M₂ 2. Maxille - N Ganglien des Nervensystems - Ni Niere (Antennendrüse) - Oe Oesophagus - Ol Oberlippe - Pl Plasma - Py Pylorusmagen - Qv Querverbindung zwischen den Kopflappen - pR perivitelliner Raum - Seg Segment - Sf Sternalfurche - Sto Stomodaeum (Anlage des Vorderdarmes) - TA Thoracoabdominalanlage - Te Telson - Ul Urdarmlumen - V Vitellophage (primare Dotterzelle) - V ₁ Vitellophage 1 (1. Vitellophagengeneration) - V ₂ Vitellophage 2 (2. Vitellophagengeneration) - dV degenerierende Vitellophage - V intravitelline Vitellophage - IV Initialvitellophage (Lumenbildung) - pV perivitelline Vitellophage - Va Vakuole - Vi gelöster Dotter (im Darmlumen) - fZ freie Zellen (im perivitellinen Raum) Ausgeführt mit Mitteln des Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung and der Freiwillig Akademischen Gesellschaft der Stadt Basel.     

Ultrahistochemical and autoradiographic evidence for epithelial transport in the uterus of the ovoviviparous salamander,Salamandra salamandra (L.) (Amphibia,Urodela)

Summary The uterine epithelium of pregnant females of the terrestrial ovoviviparous Salamandra salamandra is characterized by a considerable enlargement of its basolateral surface. Chloride and cations (among others sodium), preferentially within the intercellular spaces, can be demonstrated ultrahistochemically. There is indirect evidence of Na⁺-K⁺-ATPase activity along the basolateral plasma membranes of the epithelial cells using the Sr-technique for demonstration of a K⁺-NPPase and ³H-ouabain autoradiography. Preliminary measurements reveal a potential difference across the uterine wall of 15–25mV, the lumenal (mucosal) surface being negative with respect to the coelomic (serosal) surface, and a short circuit current of 200–300 A. The possibly electrogenic ion transport is ouabain-sensitive. The results are in agreement with the model of a forward transporting, i.e. absorptive epithelium. An active transport of solute out of the uterine lumen across the epithelium to the subjacent connective tissue and the blood vessels may be involved in the regulation of an intrauterine milieu appropriate for the development of the offspring.I am indebted to Miss Dr. U. Beigel, Zoologisches Institut der Universität Münster, for linguistic help