Triploidy—Observations in 154 Diandric Cases

Hydatidiform moles (HMs) are abnormal human pregnancies with vesicular chorionic villi, imposing two clinical challenges; miscarriage and a risk of gestational trophoblastic neoplasia (GTN). The parental type of most HMs are either diandric diploid (PP) or diandric triploid (PPM). We consecutively collected 154 triploid or near-triploid samples from conceptuses with vesicular chorionic villi. We used analysis of DNA markers and/or methylation sensitive-MLPA and collected data from registries and patients records. We performed whole genome SNP analysis of one case of twinning (PP+PM).In all 154 triploids or near-triploids we found two different paternal contributions to the genome (P1P2M). The ratios between the sex chromosomal constitutions XXX, XXY, and XYY were 5.7: 6.9: 1.0. No cases of GTN were observed. Our results corroborate that all triploid human conceptuses with vesicular chorionic villi have the parental type P1P2M. The sex chromosomal ratios suggest approximately equal frequencies of meiosis I and meiosis II errors with selection against the XYY conceptuses or a combination of dispermy, non-disjunction in meiosis I and meiosis II and selection against XYY conceptuses. Although single cases of GTN after a triploid HM have been reported, the results of this study combined with data from previous prospective studies estimate the risk of GTN after a triploid mole to 0% (95% CI: 0–1,4%).     

G-quadruplexes are specifically recognized and distinguished by selected designed ankyrin repeat proteins

We introduce designed ankyrin repeat binding proteins (DARPins) as a novel class of highly specific and structure-selective DNA-binding proteins, which can be functionally expressed within all cells. Human telomere quadruplex was used as target to select specific binders with ribosome display. The selected DARPins discriminate the human telomere quadruplex against the telomeric duplex and other quadruplexes. Affinities of the selected binders range from 3 to 100 nM. CD studies confirm that the quadruplex fold is maintained upon binding. The DARPins show different specificity profiles: some discriminate human telomere quadruplexes from other quadruplex-forming sequences like ILPR, c-MYC and c-KIT, while others recognize two of the sequences tested or even all quadruplexes. None of them recognizes dsDNA. Quadruplex-binding DARPins constitute valuable tools for specific detection at very small scales and for the in vivo investigation of quadruplex DNA.     

The substitution of arginine for glycine 85 of the alpha 1(I) procollagen chain results in mild osteogenesis imperfecta. The mutation provides direct evidence for three discrete domains of cooperative melting of intact type I collagen.

We report a case of mild osteogenesis imperfecta in a 56-year-old male undergoing aortic valve replacement surgery. The primary defect in this patient was the substitution of arginine for glycine 85 in one of the two chains of alpha 1(I) procollagen. The thermal stability of the type I collagen synthesized by the patient's cultured skin fibroblasts was examined by enzymatic digestion. Digestion of the mutant type I collagen with trypsin and chymotrypsin at increasing temperatures sequentially generated three discrete collagenous fragments, approximately 90, 170, and 230 amino acids shorter than normal type I collagen. This incremental thermal denaturation is indicative of cooperative melting blocks within the type I collagen. This is the first demonstration of such cooperative blocks of melting in intact, essentially normal post-translationally modified type I collagen. This direct evidence for cooperative melting domains of uncut type I collagen suggests that discrete blocks of amino acids function as core sites stabilizing the collagen helix. The location of mutations of the alpha chains of type I collagen relative to these discrete blocks of amino acids may influence the severity of the disease phenotype.     

Advantages of arthroscopy of the knee joint]

Arthroscopic surgery causes considerably less soft tissue damage than conventional surgery. As the result of the development of an optical system employed with a chip camera and a video chain arthroscopic knee surgery can be ideally documented with excellent picture quality. Besides the advantage of soft-tissue sparing procedures, diagnosis is substantially improved and operative procedures can be kept to a minimum. This means, in particular in the case of meniscus procedures, that only the damaged areas are removed, this minimising changes to the biomechanics of the knee. The technical equipment, the arthroscopic surgery technic and the advantages of the knee arthroscopy are discussed.     

Neuronal mechanisms contributing to long-term sensitization in Aplysia

1.) Cellular processes that contribute to the acquisition and expression of long-term sensitization have been examined in Aplysia. The tail-siphon withdrawal reflex was studied because the neural circuit for this reflex has been well characterized. Furthermore, the sensory neurons of this neural circuit exhibit cellular changes that accompany short-term sensitization. 2.) Repeated application of noxious stimuli to the animal produces a long-lasting enhancement of reflex withdrawal of the siphon when the animal is tested with a weak stimulus to the tail. These findings confirm the existence of long-term sensitization in Aplysia, first described by Pinkser et al. (1973). 3.) Biophysical correlates of long-term sensitization were examined in the first central relay of the tail-siphon reflex circuit, the sensory neurons that innervate the animal's tail. The net outward membrane currents of these cells reduced after 24 hours as a consequence of long-term sensitization training. 4.) The intracellular signal for the induction of these changes in membrane currents was examined by intracellular injection of cAMP into individual sensory neurons. This procedure mimics at least some of the effects of sensitization training at the single-cell level. cAMP induced a long-term reduction of membrane K+ currents 24 hours after the cells were injected with cAMP. The membrane currents reduced by cAMP were similar to those reduced by long-term sensitization training. 5.) Preliminary experiments indicate that neurotransmitters and agents that induce an evaluation of cAMP in the sensory neurons also alter the incorporation of labeled amino acids into specific proteins in the sensory neurons.(ABSTRACT TRUNCATED AT 250 WORDS)     

Validation of density–elasticity relationships for finite element modeling of human pelvic bone by modal analysis

In total hip arthroplasty and particularly in revision surgery, computer assisted pre-operative prediction of the best possible anchorage strategy for implant fixation would be a great help to the surgeon. Computer simulation relies on validated numerical models. In the current study, three density–elasticity relationships (No. 1–3) from the literature for inhomogeneous material parameter assignment from CT data in automated finite element (FE) modeling of long bones were evaluated for their suitability for FE modeling of human pelvic bone. Numerical modal analysis was conducted on 10 FE models of hemipelvic bone specimens and compared to the gold standard provided by experimental modal analysis results from a previous in-vitro study on the same specimens. Overall, calculated resonance frequencies came out lower than measured values. Magnitude of mean relative deviation of numerical resonance frequencies with regard to measured values is lowest for the density–elasticity relationship No. 3 (−15.9%) and considerably higher for both density–elasticity relationships No. 1 (−41.1%) and No. 2 (−45.0%). Mean MAC values over all specimens amount to 77.8% (No. 1), 78.5% (No. 2), and 83.0% (No. 3). MAC results show, that mode shapes are only slightly influenced by material distribution. Calculated resonance frequencies are generally lower than measured values, which indicates, that numerical models lack stiffness. Even when using the best suited (No. 3) out of three investigated density–elasticity relationships, in FE modeling of pelvic bone a considerable underestimation of model stiffness has to be taken into account.     

Neuronal Basis of Innate Olfactory Attraction to Ethanol in Drosophila

The decision to move towards a mating partner or a food source is essential for life. The mechanisms underlying these behaviors are not well understood. Here, we investigated the role of octopamine – the invertebrate analogue of noradrenaline – in innate olfactory attraction to ethanol. We confirmed that preference is caused via an olfactory stimulus by dissecting the function of the olfactory co-receptor Orco (formally known as OR83b). Orco function is not required for ethanol recognition per se, however it plays a role in context dependent recognition of ethanol. Odor-evoked ethanol preference requires the function of Tbh (Tyramine β hydroxalyse), the rate-limiting enzyme of octopamine synthesis. In addition, neuronal activity in a subset of octopaminergic neurons is necessary for olfactory ethanol preference. Notably, a specific neuronal activation pattern of tyraminergic/octopaminergic neurons elicit preference and is therefore sufficient to induce preference. In contrast, dopamine dependent increase in locomotor activity is not sufficient for olfactory ethanol preference. Consistent with the role of noradrenaline in mammalian drug induced rewards, we provide evidence that in adult Drosophila the octopaminergic neurotransmitter functions as a reinforcer and that the molecular dissection of the innate attraction to ethanol uncovers the basic properties of a response selection system.     

Activation of Ca2+/Calmodulin-Dependent Protein Kinase II by Extracellular Calcium in Cultured Hippocampal Pyramidal Neurons

Abstract: The ability of various stimuli to convert Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) into a Ca²⁺-independent (autonomous) form was examined in cultured embryonic rat hippocampal pyramidal neurons. The most effective stimulation by far was observed when cells were equilibrated in buffer containing low extracellular [Ca²⁺] ([Ca²⁺]_o) (～50 nM) and then shifted to normal [Ca²⁺]_o (～1.26 mM) by addition of CaCl₂ (referred to as “Ca²⁺ stimulation”). Virtually complete (>90%) conversion of the kinase to the autonomous form occurred within 30–50 s, with a return to baseline within 5 min. By contrast, depolarization of cells with high [K⁺] or treatment with glutamate or a Ca²⁺ ionophore caused insignificant increases (<10%) in levels of the autonomous form. The Ca²⁺-stimulated increase in CaMKII autonomy coincided with a two- to threefold increase in kinase subunit phosphorylation. In the first 40 s of Ca²⁺ stimulation, ³²P incorporation into the immunoprecipitated subunits of CaMKII occurred exclusively on threonine residues, including Thr²⁸⁶Thr²⁸⁷ of the α/β subunits. Longer incubation of cells resulted in a decline of phosphothreonine content, whereas levels of phosphoserine-containing peptides showed a significant increase. The activation of CaMKII by Ca²⁺ stimulation was accompanied by only a small rise in intracellular [Ca²⁺]. Inhibitor studies showed that Na⁺-dependent action potentials and Ca²⁺ influx through glutamate receptors or voltage-sensitive Ca²⁺ channels did not contribute to the activation. Moreover, CaMKII was not activated by extracellular addition of other cations, including Mn²⁺, Mg²⁺, Co²⁺, or Gd³⁺. Although the mechanism of Ca²⁺ stimulation is presently unclear, it may involve either activation of extracellular calcium receptors or capacitative calcium entry. The dramatic rise in CaMKII autonomy and the Ca²⁺ selectivity of the response suggest a direct and specific relationship between [Ca²⁺]_o and the state of activation of the kinase in intact neurons.