Acetabular Fractures in an Advanced Age - Current Knowledge and Treatment Options.

The demographic change in industrial countries leads to an increasing population that sustains an acetabular fracture in an advanced age. Some authors predicted elderly individuals to be the most rapidly growing subgroup of patients currently sustaining acetabular fractures. Gold standard of treatment of acetabular fractures remains the open reduction and internal fixation. Relevant factors impeding surgical treatment include the significantly decreased bone stock and the incapability of the patients to partially weight bear following surgery. Therefore, special considerations should be performed when dealing with this patient group as surgical treatment is associated with several risks and often accompanied by poor outcomes. This review aims to summarize the current body of knowledge and to give a recommendation concerning a surgical treatment cascade.

[Operative therapy of fractures of the distal femur. Predictive factors for a complicated course]. / Operative Therapie von distalen Femurfrakturen. Prognostische Faktoren für einen komplikationsbehafteten Verlauf.

BACKGROUND: Fractures of the distal femur are rare injuries that are mainly treated operatively. Complication rates remain high. OBJECTIVES: This study aimed to analyse complications following the operative treatment of these fractures and to identify predictive factors that have the potential to identify patients who are at risk for a complicated course of treatment. MATERIALS AND METHODS: We retrospectively analysed all fractures of the distal femur that were treated operatively at our institution between 2005 and 2015. Besides patient and fracture-specific data, surgical details and the types of complications that occurred were recorded and analysed. RESULTS: Open soft tissue damage, the polytraumatised patient and the timing of surgery (i.e. emergency surgery) are significant risk factors for the development of a nonunion. A risk factor that predicts a postoperative infection is open soft tissue damage. Type C fractures, stabilisation as emergency surgery and an accompanying polytrauma are risk factors for a postoperative pneumonia. CONCLUSIONS: The complication rate is significantly determined by surgical factors. To reduce the rate of nonunion, infection and pneumonia, the optimisation of the patient's general condition before surgery and optimal surgical care is more important than an immediate emergency surgery.

Nucleotide diversity of a genomic sequence similar to SHATTERPROOF (PvSHP1) in domesticated and wild common bean (Phaseolus vulgaris L.).

Evolutionary studies in plant and animal breeding are aimed at understanding the structure and organization of genetic variations of species. We have identified and characterized a genomic sequence in Phaseolus vulgaris of 1,200 bp (PvSHP1) that is homologous to SHATTERPROOF-1 (SHP1), a gene involved in control of fruit shattering in Arabidopsis thaliana. The PvSHP1 fragment was mapped to chromosome Pv06 in P. vulgaris and is linked to the flower and seed color gene V. Amplification of the PvSHP1 sequence from the most agronomically important legume species showed a high degree of interspecies diversity in the introns within the Phaseoleae, while the coding region was conserved across distant taxa. Sequencing of the PvSHP1 sequence in a sample of 91 wild and domesticated genotypes that span the geographic distribution of this species in the centers of origin showed that PvSHP1 is highly polymorphic and, therefore, particularly useful to further investigate the origin and domestication history of P. vulgaris. Our data confirm the gene pool structure seen in P. vulgaris along with independent domestication processes in the Andes and Mesoamerica; they provide additional evidence for a single domestication event in Mesoamerica. Moreover, our results support the Mesoamerican origin of this species. Finally, we have developed three indel-spanning markers that will be very useful for bean germplasm characterization, and particularly to trace the distribution of the domesticated Andean and Mesoamerican gene pools.

Beans in Europe: origin and structure of the European landraces of Phaseolus vulgaris L.

This study focuses on the expansion of Phaseolus vulgaris in Europe. The pathways of distribution of beans into and across Europe were very complex, with several introductions from the New World that were combined with direct exchanges between European and other Mediterranean countries. We have analyzed here six chloroplast microsatellite (cpSSR) loci and two unlinked nuclear loci (for phaseolin types and Pv-shatterproof1). We have assessed the genetic structure and level of diversity of a large collection of European landraces of P. vulgaris (307) in comparison to 94 genotypes from the Americas that are representative of the Andean and Mesoamerican gene pools. First, we show that most of the European common bean landraces (67%) are of Andean origin, and that there are no strong differences across European regions for the proportions of the Andean and Mesoamerican gene pools. Moreover, cytoplasmic diversity is evenly distributed across European regions. Secondly, the cytoplasmic bottleneck that was due to the introduction of P. vulgaris into the Old World was very weak or nearly absent. This is in contrast to evidence from nuclear analyses that have suggested a bottleneck of greater intensity. Finally, we estimate that a relatively high proportion of the European bean germplasm (about 44%) was derived from hybridization between the Andean and Mesoamerican gene pools. Moreover, although hybrids are present everywhere in Europe, they show an uneven distribution, with high frequencies in central Europe, and low frequencies in Spain and Italy. On the basis of these data, we suggest that the entire European continent and not only some of the countries therein can be regarded as a secondary diversification center for P. vulgaris. Finally, we outline the relevance of these inter-gene pool hybrids for plant breeding.

Introgression from modern hybrid varieties into landrace populations of maize (Zea mays ssp. mays L.) in central Italy.

Landraces are domesticated local plant varieties that did not experience a deliberate and intensive selection during a formal breeding programme. In Europe, maize landraces are still cultivated, particularly in marginal areas where traditional farming is often practiced. Here, we have studied the evolution of flint maize landraces from central Italy over 50 years of on-farm cultivation, when dent hybrid varieties were introduced and their use was widespread. We have compared an 'old' collection, obtained during the 1950s, before the introduction of hybrids, and a recent collection of maize landraces. For comparison, a sample of maize landraces from north Italy, and of improved germplasm, including hybrids and inbred lines were also used. A total of 296 genotypes were analysed using 21 microsatellites. Our results show that the maize landraces collected in the last 5-10 years have evolved directly from the flint landrace gene pool cultivated in central Italy before the introduction of modern hybrids. The population structure, diversity and linkage disequilibrium analyses indicate a significant amount of introgression from hybrid varieties into the recent landrace populations. No evidence of genetic erosion of the maize landraces was seen, suggesting that in situ conservation of landraces is an efficient strategy for preserving genetic diversity. Finally, the level of introgression detected was very variable among recent landraces, with most of them showing a low level of introgression; this suggests that coexistence between different types of agriculture is possible, with the adoption of correct practices that are aimed at avoiding introgression from undesired genetic sources.

Water near intracellular surfaces.

In this paper we make the following points: Water is perturbed within several angstroms of the surfaces of soluble molecules. Removal of this water can require significant amounts of work, seen as an exponentially varying "hydration force" with respect to molecular separation. The favorable and specific attractions that occur in molecular assembly or in ligand binding imply that the specific association between the molecular surfaces is stronger than the association of those surfaces with water. The specificity of biochemical association is not simply a matter of protein-protein interaction but also of competing protein-water interactions. Small structural changes in molecular surfaces can evoke large changes in the contact energy of hydrated surfaces; surface hydration and the energetics of water displacement are a likely mechanism for the contact specificity of intracellular associations integrating the cell matrix.

Higher order structure in a short repeat length chromatin.

Polynucleosomes from calf brain cortical neurone nuclei have an average repeat length of less than 168 base pairs. The ability of this material to adopt higher order structure has been assessed by various physical techniques. Although containing on average less DNA per nucleosome than is required to form a chromatosome, this short repeat length chromatin folded in an H1 dependent manner to a structure with properties similar to those observed for longer repeat length chromatins such as that of chicken erythrocyte (McGhee, J.D., D.C. Rau, E. Charney, and G. Felsenfeld, 1980, Cell, 22:87-96). These observations are discussed in the context of H1 location in the higher order chromatin fiber.

Participation of core histone "tails" in the stabilization of the chromatin solenoid.

We show here that the solenoid is maintained by the combination of linker histones and the nonglobular, highly basic "tails" of the core histones, which play only a minor part in the formation of the nucleosome core (Whitlock and Simpson, 1977. J. Biol. Chem. 252:6,516--6,520; Lilley and Tatchell, 1977. Nucleic Acids Res. 4:2,039--2,055; and Whitlock and Stein, 1978. J. Biol. Chem. 253:3,857--3,861). Polynucleosomes that contain core histones devoid of tails remain substantially unfolded under conditions otherwise favorable for the formation of solenoids. The tails can be replaced by extraneous basic polypeptides and in the presence of the linker histones the solenoid structure is then spontaneously recovered, as judged by a wide variety of structural criteria. The inference is that the core histone tail segments function by providing electrostatic shielding of the DNA charge and at the same time bridging adjacent nucleosomes in the solenoid. Our results carry the further implication that posttranscriptional modifications, such as acetylation of epsilon-amino groups, that reduce the positive charge of the core histone tails will tend to destabilize the higher-order structure and could thus render the DNA with which they are associated more readily available for transcription.

Direct measurement of forces between linear polysaccharides xanthan and schizophyllan.

Direct osmotic stress measurements have been made of forces between helices of xanthan, an industrially important charged polysaccharide. Exponentially decaying hydration forces, much like those already measured between lipid bilayer membranes or DNA double helices, dominate the interactions at close separation. Interactions between uncharged schizophyllans also show the same kind of hydration force seen between xanthans. In addition to the practical possibilities for modifying solution and suspension properties through recognition and control of molecular forces, there is now finally the opportunity for theorists to relate macroscopic properties of a polymer solution to the microscopic properties that underlie them.

Protein solvation in allosteric regulation: a water effect on hemoglobin.

The oxygen affinity of hemoglobin varies linearly with the chemical potential of water in the bathing medium, as seen from the osmotic effect of several neutral solutes, namely sucrose, stachyose, and two polyethyleneglycols (molecular weights of 150 and 400). The data, analyzed either by Wyman linkage equations or by Gibbs-Duhem relations, show that approximately 60 extra water molecules bind to hemoglobin during the transition from the fully deoxygenated tense (T) state to the fully oxygenated relaxed (R) state. This number, independent of the nature of the solute, agrees with the difference in water-accessible surface areas previously computed for the two conformations. The work of solvation in allosteric regulation can no longer go unrecognized.

CSF proteome analysis in clinically isolated syndrome (CIS): candidate markers for conversion to definite multiple sclerosis.

Cerebrospinal fluid (CSF) is a promising source of biomarkers in clinically isolated syndrome (CIS), which frequently presents as a first episode of multiple sclerosis (MS). Using the two-dimensional difference in gel electrophoresis (2-D DIGE), we compared CSF samples from patients with CIS that remained CIS (CIS-CIS, n=8) over a follow-up time of 2 years and from patients with CIS that developed definite MS of the relapsing-remitting subtype (CIS-RRMS, n=8) over the same period. Protein spots that showed significant differences between patients and controls were selected for further analysis by MALDI-TOF mass spectrometry. For validation of identified spots ELISA experiments were performed. We identified one protein that was upregulated in CIS-RRMS (serin peptidase inhibitor) and eight proteins (alpha-1-B-glycoprotein, Fetuin-A, apolipoprotein A4, haptoglobin, human Zinc-alpha-2-glycoprotein (ZAG), Retinol-binding protein, superoxid dismutase 1, transferrin) that were down-regulated in CIS-RRMS vs. CIS-CIS. For Fetuin-A, our findings could be confirmed by ELISA. The pathophysiological role as well as clinical relevance of these candidate proteins in CIS remains to be further clarified by future studies.

Development and use of chloroplast microsatellites in Phaseolus spp. and other legumes.

Chloroplast microsatellites (cpSSRs) provide a powerful tool to study the genetic variation and evolution of plants. We have investigated the usefulness of 39 primer pairs tagging cpSSR loci on a set of eight different genera of Leguminosae (Papilionoideae subfamily) and five species belonging to the genus Phaseolus. Thirty-six 'universal' primer pairs were retrieved from the literature, one was re-designed and a further two were designed de novo. The cpSSR loci analysed were highly polymorphic across the individuals examined. Twenty-seven primer pairs were polymorphic in the overall sample, 18 within Phaseolus, and 16 in both P. vulgaris and P. coccineus. Analysis of the plastome sequences of four Leguminosae species (obtained from GenBank) showed that in the loci targeted by universal primer pairs: (i) the originally tagged cpSSRs can be lost; (ii) other cpSSRs can be present; and (iii) polymorphism arises not only from differences in the numbers of cpSSR repeats, but often from other insertion/deletion events. Multilocus linkage disequilibrium analysis suggests that homoplasy is not a major problem in our dataset, and principal component analysis indicates intelligible relationships among the species considered. Our study demonstrates that this set of chloroplast markers provides a useful tool to study the diversity and the evolution of several legumes, and particularly P. vulgaris and P. coccineus.

DNA--DNA interactions.

The forces that govern DNA double helix organization are being finally systematically measured. The non-specific longer-range interactions--such as electrostatic interactions, hydration, and fluctuation forces--that treat DNA as a featureless rod are reasonably well recognized. Recently, specific interactions--such as those controlled by condensing agents or those consequent to helical structure-are beginning to be recognized, quantified and tested.

Spatial genetic structure in wild cardoon, the ancestor of cultivated globe artichoke: Limited gene flow, fragmentation and population history.

Nuclear and chloroplast markers and phenotypic characters were integrated to analyse the population genetic structure of wild cardoon, Cynara cardunculus var. sylvestris, the ancestor of cultivated globe artichoke, Cynara cardunculus var. scolymus on the island of Sardinia, Italy. The spatial scale ranged from a few metres to ∼200km. Wild cardoon appears to be genetically fragmented, with significant genetic divergence at various scales, indicating that gene flow is insufficient to counterbalance the effects of genetic drift or founder effects. Divergence between populations was higher for chloroplast (40%) than for nuclear markers (15%), suggesting that gene flow via seed was lower than via pollen. Two main genetic groups were detected; these correlated with differences in flowering time, capitula size, glossiness, and anthocyanin pigmentation. A complex population structure of wild cardoon emerged over small spatial scales, likely resulting from the interplay between gene dispersal, colonisation history and selective forces. Indeed, Sardinia appears to be a 'hybrid zone' of different gene pools. The island has unique diverse germplasm that has originated from hybridisation among different gene pools. The sampling of seeds from a few plants but from many sites is suggested as the best strategy to harvest the genetic diversity of wild cardoon.

Zinc induces a bend within the transcription factor IIIA-binding region of the 5 S RNA gene.

Binding of Zn2+ to the 5 S RNA gene sequence of Xenopus borealis results in strong bending of the DNA, as inferred from transient electric birefringence data. The effect is specific for Zn2+; several other divalent ions are not able to induce a bend of a similar magnitude. Using five different fragments that span the binding sequence, we are able to estimate a bend magnitude of at least 55 degrees centered at base-pair +65 within the gene. This places the bend within the binding domain of the gene-regulatory protein transcription factor (TF) IIIA. Recent evidence has shown that the protein-DNA complex is also bent. Although our data do not allow us directly to link the two bends, our results suggest that TFIIIA could form a folded structure by stabilizing the same bent conformation that is induced by binding of Zn2+. The chemistry of Zn2+ binding to DNA, and the sequence around the bend center, suggest that the bend is most probably caused by joint co-ordination of Zn2+ to the N-7 groups of stacked purine residues.

Linkage of EcoRI dissociation from its specific DNA recognition site to water activity, salt concentration, and pH: separating their roles in specific and non-specific binding.

We have measured the dependencies of both the dissociation rate of specifically bound EcoRI endonuclease and the ratio of non-specific and specific association constants on water activity, salt concentration, and pH in order to distinguish the contributions of these solution components to specific and non-specific binding. For proteins such as EcoRI that locate their specific recognition site efficiently by diffusing along non-specific DNA, the specific site dissociation rate can be separated into two steps: an equilibrium between non-specific and specific binding of the enzyme to DNA, and the dissociation of non-specifically bound protein. We demonstrated previously that the osmotic dependence of the dissociation rate is dominated by the equilibrium between specific and non-specific binding that is independent of the osmolyte nature. The remaining osmotic sensitivity linked to the dissociation of non-specifically bound protein depends significantly on the particular osmolyte used, indicating a change in solute-accessible surface area. In contrast, the dissociation of non-specifically bound enzyme accounts for almost all the pH and salt-dependencies. We observed virtually no pH-dependence of the equilibrium between specific and non-specific binding measured by the competition assay. The observed weak salt-sensitivity of the ratio of specific and non-specific association constants is consistent with an osmotic, rather than electrostatic, action. The seeming lack of a dependence on viscosity suggests the rate-limiting step in dissociation of non-specifically bound protein is a discrete conformational change rather than a general diffusion of the protein away from the DNA.

Structure of the DNA gyrase-DNA complex as revealed by transient electric dichroism.

We have analyzed the structure of complexes between DNA gyrase and four defined DNA fragments by electric dichroism. Both the extrapolated dichroism and relaxation time of these complexes suggest that a single turn of DNA is wrapped around the enzyme with the entry and exit points located close together. The average angle between the DNA tails emerging from the particle is about 120 degrees. This structure is consistent with that seen by electron microscopy. Addition of ATP or the non-hydrolyzable ATP analog 5'-adenylyl-beta, gamma-imidodiphosphate results in a structural change of the complex, consistent with the DNA tails now being wrapped around the protein. The significance of these observations with respect to the mechanism of DNA supercoiling by DNA gyrase is discussed.

Cytogenetic studies in lymphocytes of patients with rectal cancer.

Spontaneous and clastogen-induced chromosomal instability in a high-risk group (i.e, 33 patients with rectal carcinomas) was investigated using peripheral blood lymphocytes as target cells. In addition to the analysis of spontaneous and clastogen-induced chromosome aberrations, this study also included classical karyotype analysis and scoring of sister chromatid exchanges (SCE) in some of the patients. Diepoxybutane (DEB), 4-nitroquinoline-1-oxide (NQO), and bleomycin were used as standard clastogens. Lymphocytes of healthy control individuals were studied in parallel with each cancer patient. While only slight but significant differences could be detected of the average spontaneous, DEB- and bleomycin (G2)-induced chromosome breakage between patient and control lymphocytes, individual patients and two of the control individuals showed a more distinct increase in the frequency of the studied end points. These increases were documented by a variegated mosaicism of karyotypic changes and by an increased breakage rate induced by the clastogens. Neither the bleomycin-exposure in the G1 phase nor SCE was capable of detecting differences between the patients and controls. Of particular interest in the sense of high-risk individuals were seven patients and two control persons whose lymphocytes exhibited increased chromosomal sensitivity under more than one of the studied experimental conditions.

Electric dichroism of DNA. Influence of the ionic environment on the electric polarizability.

In order to test the diffuse ion atmosphere polarization model recently developed by us, the effects of ionic strength, titrating with Mg2+ and Co(NH3)3+6, and coion charge on the electric polarizability of short fragments of DNA are investigated. The results are consistent with the predictions of the theory and show that the diffuse ion atmosphere polarization contributes significantly to the overall orientation of DNA. At low ionic strengths, we attempt to separate the total dipole moment into two components: one that agrees well with the Debye-Hückel ion atmosphere calculations, while the other, presumably due to condensed counterion polarization, appears to be substantially independent of the ionic strength. At higher salt concentrations, however, a simple separation into dipole components is not possible, perhaps due to a significant coupling of ion flows between the diffuse atmosphere and the condensed counterion layer.