[Protein glycation as a pathological mechanism in diabetes]. / Proteinglykierung als pathophysiologischer Mechanismus bei Diabetes.

The incidence of diabetes has increased in the recent years. Diabetes is characterized by increased sugar concentrations in the blood. Due to this dysregulation, more carbohydrate-induced modification of proteins - so-called advanced glycation end products (AGEs) - are formed endogenously by non-enzymatic reactions. These are discussed to be at least in part responsible for diabetes-associated diseases. The accumulation of AGEs in the tissue can be used as a biomarker for patient outcome. In contrast, the effects of the uptake of AGEs from nutrition are still unclear.

RAGE influences obesity in mice. Effects of the presence of RAGE on weight gain, AGE accumulation, and insulin levels in mice on a high fat diet.

BACKGROUND: The metabolic syndrome is defined by the presence of obesity, insulin resistance, dyslipidemia, and hypertension. Advanced glycation end products (AGEs) are stable end products of the Maillard reaction, whereby AGE accumulation is considered not only a biomarker of aging but is also associated with several degenerative diseases. AGEs are recognized by several receptor molecules of which the receptor of AGEs (RAGE) is currently the most intensively studied receptor. Activation of RAGE causes an unfavorable proinflammatory state and deletion of RAGE in diabetic animals has been reported to protect against atherosclerosis. AGEs and a high fat diet are associated with cardiovascular diseases, whereas is still not clear whether a direct link between high fat nutrition and AGEs exists in vivo. MATERIALS AND METHODS: C57BL/6 and C57BL/6 RAGE -/- mice were fed a high fat diet to induce obesity. Weight, insulin, lipid levels, AGE modifications, and cardiac gene expression were analyzed. RESULTS: The absence of RAGE resulted in accelerated weight gain, increased plasma cholesterol, and higher insulin levels in obese mice. The hearts of normal and obese RAGE -/- mice contained lower levels of the AGE arginine-pyrimidine and 3DG-imidazolone than RAGE + / + animals. RAGE -/- mice also exhibited lower expression of the genes encoding the antioxidative enzymes MnSOD, Cu/ZnSOD, and ceruloplasmin in cardiac tissue, whereas the AGE receptors AGER-1, -2, and -3 were equally expressed in both genotypes. Obese mice of both strains expressed increased amounts of AGER-2. Only obese RAGE + / + mice exhibited a reduced mRNA accumulation of Cu/Zn SOD. CONCLUSION: These data suggest that RAGE is involved in the development of obesity and insulin resistance.

Care-seeking behavior for neonatal jaundice in rural northern Nigeria.

Objective: This study determined the predictors of maternal knowledge and health-seeking behavior for neonatal jaundice in rural Kumbotso, northern Nigeria. Study design: Cross-sectional survey. Method: A total of 361 mothers were interviewed using structured questionnaires. Knowledge scores and care-seeking practices were determined. Adjusted odds ratios were generated from logistic regression models. Results: The proportion of respondents with good, fair and poor knowledge of neonatal jaundice were (46.0%, n â€‹= â€‹166), (24.1%, n â€‹= â€‹87) and (30.0%, n â€‹= â€‹108), respectively. Of the 117 mothers with a jaundiced child, (67.5%, n â€‹= â€‹79) and (20.5%, n â€‹= â€‹24) received treatment from health facilities and traditional healers, respectively, whereas (12.0%, n â€‹= â€‹14) resorted to home remedies. Maternal education Adjusted Odds Ratio (AOR) â€‹= â€‹2.39; 95% Confidence Interval (CI): 1.16-4.91) (secondary school versus no formal), source of information on neonatal jaundice (AOR â€‹= â€‹11.3; 95%CI: 5.84-21.93) (health worker versus 'others'), recent delivery in a health facility (AOR â€‹= â€‹1.83; 95%CI: 1.06-3.14) and having a previously jaundiced child (AOR â€‹= â€‹5.06; 95%CI: 2.76-9.27) predicted knowledge. Preference for health facility treatment was predicted by a previously jaundiced child (AOR â€‹= â€‹10.04; 95%CI: 5.73-17.60), antenatal care (AOR â€‹= â€‹2.97; 95%CI: 1.43-6.15) (≥4 versus 0 visits), source of information on neonatal jaundice (AOR â€‹= â€‹2.33; 95%CI: 1.30-4.17) (health worker versus 'others'), and maternal ethnicity (AOR â€‹= â€‹0.36; 95%CI: 0.14-0.96) (Hausa-Fulani versus 'others'). Conclusion: Maternal knowledge of neonatal jaundice was sub-optimal. Being educated, health facility delivery, having had a jaundiced child, and receiving information from health workers predicted good knowledge. Having a previously jaundiced child, antenatal care, obtaining information from health workers and maternal ethnicity predicted preference for health facility treatment. Policies and programs should be strengthened to focus on prevention, early detection and prompt management of neonatal jaundice.

Advanced glycation endproducts: a biomarker for age as an outcome predictor after cardiac surgery?

OBJECTIVE: A decline in the function of all organs can be detected during ageing. Although the trend appears to be stable, deviation within the elderly population is much greater in comparison to young controls. The aim of the study was to identify a marker of senescence which correlates to heart function. Advanced glycation endproducts (AGEs) accumulate with age and are associated with degenerative diseases. METHODS: Carboxymethyllysine (CML) concentrations in the pericardial fluid (as a measure of AGEs) were analysed with ELISA technique in 75 patients undergoing cardiac surgery and correlated with clinical parameters and outcome of these patients. RESULTS: CML content of pericardial fluid increases significantly with age. AGEs show an inverse correlation to left ventricular ejection fraction. High CML levels correlate with poor outcome of patients as shown by adverse cardiac events, prolonged ventilation time and prolonged stay within the Intensive Care Unit. Within all parameters, AGE concentration of the pericardial fluid fits better with the outcome of the patients in comparison to age alone. Interestingly, medical treatment with nitrates correlates with increased CML content. CONCLUSION: AGEs, in addition to being a marker of senescence, appear to represent a prognostic factor in cardiac surgery, which can be used as a predictor of patient outcome.

The yptV1 gene encodes a small G-protein in the green alga Volvox carteri: gene structure and properties of the gene product.

Small G-proteins encoded by ras-like genes are ubiquitous in eukaryotic cells. These G-proteins are believed to play a role in central processes, such as signal transduction, cell differentiation and membrane vesicle transport. By screening genomic and cDNA libraries of the colonial alga, Volvox carteri f. nagariensis, with ypt DNA probes from Zea mays, we have identified the first member of a ypt gene family, yptV1, within a green alga. The 1538-bp yptV1 gene of V. carteri consists of nine exons and eight introns and has three potential polyadenylation sites 210, 420 and 500 bp downstream from the UGA stop codon. The derived 203-amino-acid polypeptide, YptV1, exhibits 81% similarity with Ypt1 from mouse, with the corresponding genes sharing four identical intron positions. Recombinant YptV1 (reYptV1) produced in Escherichia coli retains the ability to bind GTP after SDS-PAGE and immobilization on nitrocellulose. Immunological studies using polyclonal antibodies against reYptV1 indicate that the protein is present in the membrane fraction of a V. carteri extract and is expressed throughout the whole life-cycle of the alga. Similar to other Ras-like proteins, YptV1 contains two conserved C-terminal cysteine residues suggesting post-translational modification(s), such as isoprenylation or palmitoylation, required for membrane anchoring. The presumptive role of YptV1 in cytoplasmic vesicle transport is briefly discussed.

Recovery of regional right ventricular function after thrombolysis for pulmonary embolism.

Abnormalities in right ventricular regional and global function can occur in the setting of acute pulmonary embolism. Treatment of acute pulmonary embolism with thrombolysis is associated with significant improvement in regional and global right ventricular function.

[In vitro and in vivo investigations of a modified textile keratoprosthesis. ACTO TexKPRO]. / In-vitro- und In-vivo-Untersuchung einer modifizierten textilen Keratoprothese. ACTO TexKPRO.

BACKGROUND: Clinical application of a keratoprosthesis (KPRO) is still a challenging task. Recent developments reflect the concepts of nut and bolt, intrastromal implantation or an osteoodontokeratoprosthesis (OOKP). A new concept of a textile KPRO has been evaluated in a limited human study with considerable difficulties which after termination of the study and considerable improvements was restarted using animal experiments. MATERIALS: The ACTO TexKPRO is made from polyvinylidene difluoride (PVDF) fibers and transparent silicone. The first and second developmental stages differed in density and size of fibers and furthermore in surface modifications of the fibers and optics which were improved for the second prototype. METHODS: Implantation of the prosthesis was performed in four patients with corneal blindness and in two cases retinal disease which required surgery. In the later animal experiments surgery was performed on three rabbits. Surgery was performed by redressing the conjunctiva, opening of the eyeball with a central 6.5 mm trephination, removal of the lens and iris and implantation and suturing of the TexKPRO. If required a silicone oil endotamponade was placed. RESULTS: All eyes were stable with the keratoprosthesis. The first prototype showed conjunctival recession on the textile haptics with highly susceptible endopthalmitis risk due to infection of the PVDF so that we decided to remove the prosthesis from all eyes after one case of severe endophthalmitis occurred. The longest time of placement was 40 months and the shortest time 6 months. All eyes were restored by keratoplasty. In animals with the new haptic we found better conjunctivalization and stable implantation of the KPRO. DISCUSSION: The textile KPRO provides a stable implantation procedure and safe connection of fibers to the scleral wound bed. The optical and mechanical implantation is safe and stable. Surface epithelialization is improved with the new surface modifications and different PVDF fiber density but beforel new implantations are planned further conceptual changes will be introduced.

[Unilateral papilledema with contralateral loss of vision]. / Einseitiges Papillenödem und kontralateraler Visusverlust.

A 46-year-old woman presented with a 4-day history of headache, dizziness and blurred vision in the left eye and a 1-year history of neck pain. Fundoscopy revealed a pale optic disc in the left eye and a swollen optic disc in the right eye. Furthermore a bilateral anosmia was evident. Cranial magnetic resonance imaging (MRI) showed a mass in the anterior cranial fossa, which was classified as a WHO grade I endotheliomatous meningeoma. A Foster Kennedy syndrome was diagnosed.

Advanced glycation end products, diabetes and ageing.

Advanced glycation end products (AGEs) are formed in vivo by a non-enzymatic reaction of proteins with carbohydrates and accumulate in many tissues during ageing. They are discussed as being responsible for many age- and diabetes-related diseases. On the other hand, AGEs are formed by the heating of food and are taken up by the nutrition. The contribution of endogenously formed versus exogenous intake of AGEs to age-related diseases is still under discussion.

Enhanced luciferin entry causes rapid wound-induced light emission in plants expressing high levels of luciferase.

In-vivo imaging of transgenic tobacco plants (Nicotiana tobacum L.) expressing firefly luciferase under the control of the Arabidopsis phenylalanine ammonialyase 1 (PAL1)-promoter showed that luciferase-catalyzed light emission began immediately after the substrate luciferin was sprayed onto the leaves and reached a plateau phase after approximately 60 min. This luminescence could easily be detected for up to 24 h after luciferin application although the light intensity declined continuously during this period. A strong and rapid increase in light emission was observed within the first minutes after wounding of luciferin-sprayed leaves. However, these data did not correlate with luciferase activity analysed by an in-vitro enzyme assay. In addition, Arabidopsis plants expressing luciferase under the control of the constitutive 35S-promoter showed similar wound-induced light emission. In experiments in which only parts of the leaves were sprayed with luciferin solutions, it was shown that increased uptake of luciferin at the wound site and its transport through vascular tissue were the main reasons for the rapid burst of light produced by preformed luciferase activity. These data demonstrate that there are barriers that restrict luciferin entry into adult plants, and that luciferin availability can be a limiting factor in non-invasive luciferase assays.

Receptor-mediated increase in cytoplasmic free calcium required for activation of pathogen defense in parsley.

Transient influx of Ca(2+) constitutes an early element of signaling cascades triggering pathogen defense responses in plant cells. Treatment with the Phytophthora sojae-derived oligopeptide elicitor, Pep-13, of parsley cells stably expressing apoaequorin revealed a rapid increase in cytoplasmic free calcium ([Ca(2+)](cyt)), which peaked at approximately 1 microM and subsequently declined to sustained values of 300 nM. Activation of this biphasic [Ca(2+)](cyt) signature was achieved by elicitor concentrations sufficient to stimulate Ca(2+) influx across the plasma membrane, oxidative burst, and phytoalexin production. Sustained concentrations of [Ca(2+)](cyt) but not the rapidly induced [Ca(2+)](cyt) transient peak are required for activation of defense-associated responses. Modulation by pharmacological effectors of Ca(2+) influx across the plasma membrane or of Ca(2+) release from internal stores suggests that the elicitor-induced sustained increase of [Ca(2+)](cyt) predominantly results from the influx of extracellular Ca(2+). Identical structural features of Pep-13 were found to be essential for receptor binding, increases in [Ca(2+)](cyt), and activation of defense-associated responses. Thus, a receptor-mediated increase in [Ca(2+)](cyt) is causally involved in signaling the activation of pathogen defense in parsley.

Measurement of 3':5'cyclic AMP in biological samples using a specific monoclonal antibody.

A fast and sensitive radioimmunoassay for 3':5'cyclic AMP based on a monoclonal antibody has been worked out. Mice were immunized with protein-conjugated 2'-O-succinyl-3':5'-cyclic AMP. The monoclonal antibody detects 0.1 and 1 pmole cAMP with succinyl cAMP (125I)iodotyrosine methyl ester and (3H) cAMP, respectively, as tracers. It shows no cross-reactivity to other adenosine nucleotides up to the millimolar range; cGMP interferes only if present at a 500 fold excess. Plant and animal tissue samples as well as adenylate cyclase activity were analysed directly or after appropriate purification in case of interfering substances. Cyclic AMP levels measured in various tissues by the antibody binding assay correspond to those obtained by HPLC determination using fluorescent etheno-cAMP.

Self-incompatibility: how plants avoid illegitimate offspring.

In some families of flowering plants, a single self-incompatibility (S) locus prevents the fertilization of flowers by pollen from the same plant. Self-incompatibility of this type involves the interaction of molecules produced by the S locus in pollen with those present in the female tissues (pistil). Until recently, the pistil products of the S locus were known in only two families, the Brassicaceae (which includes the cabbages and mustards) and Solanaceae (potatoes and tomatoes). A paper in this issue of the Proceedings describes the molecules associated with self-incompatibility in a third family, the Papaveraceae (poppies). We review current research on self-incompatibility in these three families and discuss the implications of the latest findings in poppy on the likely evolution of self-incompatibility in flowering plants. We also compare research into self-incompatibility with recent progress in understanding the mechanisms by which plants overcome infection by certain pathogens.

A retrotransposon-like sequence linked to the S-locus of Nicotiana alata is expressed in styles in response to touch.

We have identified a family of repetitive sequences in the genome of Nicotiana alata named Tna1 (Transposon of N. alata). The first element we characterised was a genomic clone for the N. alata s6-ribonuclease (S6-RNase), a gene required for self-incompatibility in this species. The DNA sequence of this element resembles the integrase domain of retrotransposons of the gypsy class and is most similar to a retrotransposon from Lilium henryi. A transcript present in N.alata styles (self-incompatibility genotype S6S6) hybridized to Tna1 and accumulated in the style following either pollination or touching. This transcript was cloned from a cDNA library and was encoded by second, partial Tna1 elements. Neither the transcribed sequence nor the original Tna1 element contain an open reading frame or is likely to be able to transpose. The second element was mapped using a population of N.alata plants segregating for alleles of the self-incompatibility locus and is closely linked to the S6-allele. The Tna1 element is present in a number of Nicotiana species and appears to have been active at least twice during the evolution of this genus.

Mapping of the epitope/paratope interactions of a monoclonal antibody directed against adenosine 3',5'-monophosphate.

A series of systematically modified cyclic AMP (cAMP) analogues, including newly synthesized benzimidazole ribofuranosyl 3',5'-monophosphates was used to map the essential molecular interactions between cAMP and the monoclonal antibody 4/2C2 (mab 4/2C2) directed against 2'-O-succinoyl cAMP [Colling, Gilles, Nass, Moka & Jaenicke (1988) Second Messengers Phosphoproteins 12, 123-133]. Its paratope binds the purine base in syn conformation by dipole-dipole interactions and hydrophobic forces and/or stacking interactions. The ribose phosphate moiety is recognized by a combination of charge interactions and H-bonds to the exocyclic and the 5'-oxygen atoms and a hydrophobic interaction at the 2'-position. There is no regioselectivity for the exocyclic oxygen atoms. Compared with the known types of binding, mab 4/2C2 thus shows a new combination of molecular interactions which may be the basis of its strikingly specific recognition and binding of the cyclic adenylates. On this account mab 4/2C2 may become an important tool in studies on cAMP metabolism.