Comorbidity patterns in patients with chronic diseases in general practice

Introduction

Healthcare management is oriented toward single diseases, yet multimorbidity is nevertheless the rule and there is a tendency for certain diseases to occur in clusters. This study sought to identify comorbidity patterns in patients with chronic diseases, by reference to number of comorbidities, age and sex, in a population receiving medical care from 129 general practitioners in Spain, in 2007.

Methods

A cross-sectional study was conducted in a health-area setting of the Madrid Autonomous Region (Comunidad Autónoma), covering a population of 198,670 individuals aged over 14 years. Multiple correspondences were analyzed to identify the clustering patterns of the conditions targeted.

Results

Forty-two percent (95% confidence interval [CI]: 41.8–42.2) of the registered population had at least one chronic condition. In all, 24.5% (95% CI: 24.3–24.6) of the population presented with multimorbidity.In the correspondence analysis, 98.3% of the total information was accounted for by three dimensions. The following four, age- and sex-related comorbidity patterns were identified: pattern B, showing a high comorbidity rate; pattern C, showing a low comorbidity rate; and two patterns, A and D, showing intermediate comorbidity rates.

Conclusions

Four comorbidity patterns could be identified which grouped diseases as follows: one showing diseases with a high comorbidity burden; one showing diseases with a low comorbidity burden; and two showing diseases with an intermediate comorbidity burden.     

A taxonomic survey of lactic acid bacteria isolated from wheat (Triticum durum) kernels and non-conventional flours

In order to explore the correspondence between raw material- and mature sourdough-lactic acid bacterial (LAB) communities, 59 Italian wheat (Triticum durum) grain samples, one bran and six non-conventional flour samples were analyzed through a culture-dependent approach. The highest cell count by an agar medium specific for LAB was 2.16 log CFU/g. From about 2300 presumptive LAB (Gram-positive and catalase-negative) colonies collected, a total of 356 isolates were subjected to identification by a genetic polyphasic strategy consisting of RAPD-PCR analysis, partial 16S rRNA gene sequencing, species-specific and multiplex PCRs. The isolates were recognized as 137 strains belonging to Aerococcus, Enterococcus, Lactobacillus, Lactococcus and Pediococcus genera and a phylogram based on partial 16S rRNA genes was constructed. The species most frequently found were Enterococcus faecium, Enterococcus mundtii and Lactobacillus graminis, which are not generally reported to be typical in mature sourdoughs.     

Enhancement of insecticidal activity of Bacillus thuringiensis Cry1A toxins by fragments of a toxin-binding cadherin correlates with oligomer formation

Cry1A toxins produced by Bacillus thuringiensis bind a cadherin receptor that mediates toxicity in different lepidopteran insect larvae. Insect cadherin receptors are modular proteins composed of three domains, the ectodomain formed by 9-12 cadherin repeats (CR), the transmembrane domain and the intracellular domain. Cry1A toxins interact with three regions of the Manduca sexta cadherin receptor that are located in CR7, CR11 and CR12 cadherin repeats. Binding of Cry1A toxin to cadherin induces oligomerization of the toxin, which is essential for membrane insertion. Also, it has been reported that cadherin fragments containing the CR12 region enhanced the insecticidal activity of Cry1Ab toxin to M. sexta and other lepidopteran larvae. Here we report that cadherin fragments corresponding to CR7 and CR11 regions also enhanced the activity of Cry1Ac and Cry1Ab toxin to M. sexta larvae, although not as efficient as the CR12 fragment. A single point mutation in the CR12 region (I1422R) affected Cry1Ac and Cry1Ab binding to the cadherin fragments and did not enhance the activity of Cry1Ab or Cry1Ac toxin in bioassays. Analysis of Cry1Ab in vitro oligomer formation in the presence of wild type and mutated cadherin fragments showed a correlation between enhancement of Cry1A toxin activity in bioassays and in vitro Cry1Ab-oligomer formation. Our data shows that formation of Cry1A toxin oligomer is in part responsible for the enhancement of Cry1A toxicity by cadherin fragments that is observed in vivo.     

The crystal structure of the carboxy-terminal domain of human translation initiation factor eIF5

The carboxy-terminal domain (CTD) of eukaryotic initiation factor 5 (eIF5) plays a central role in the formation of the multifactor complex (MFC), an important intermediate for the 43 S pre-initiation complex assembly. The IF5-CTD interacts directly with the translation initiation factors eIF1, eIF2-beta, and eIF3c, thus forming together with eIF2 bound Met-tRNA(i)(Met) the MFC. In this work we present the high resolution crystal structure of eIF5-CTD. This domain of the protein is exclusively composed out of alpha-helices and is homologous to the carboxy-terminal domain of eIF2B-epsilon (eIF2Bepsilon-CTD). The most striking difference in the two structures is an additional carboxy-terminal helix in eIF5. The binding sites of eIF2-beta, eIF3 and eIF1 were mapped onto the structure. eIF2-beta and eIF3 bind to non-overlapping patches of negative and positive electrostatic potential, respectively.     

The plant Apolipoprotein D ortholog protects <Emphasis Type="Italic">Arabidopsis</Emphasis> against oxidative stress

Background  

Lipocalins are a large and diverse family of small, mostly extracellular proteins implicated in many important functions. This family has been studied in bacteria, invertebrate and vertebrate animals but little is known about these proteins in plants. We recently reported the identification and molecular characterization of the first true lipocalins from plants, including the Apolipoprotein D ortholog AtTIL identified in the plant model Arabidopsis thaliana. This study aimed to determine its physiological role in planta.     

Conformational plasticity of the Gerstmann-Sträussler-Scheinker disease peptide as indicated by its multiple aggregation pathways

The existence of several prion strains and their capacity of overcoming species barriers seem to point to a high conformational adaptability of the prion protein. To investigate this structural plasticity, we studied here the aggregation pathways of the human prion peptide PrP82-146, a major component of the Gerstmann-Sträussler-Scheinker amyloid disease.By Fourier transform infrared (FT-IR) spectroscopy, electron microscopy, and atomic force microscopy (AFM), we monitored the time course of PrP82-146 fibril formation. After incubation at 37 °C, the unfolded peptide was found to aggregate into oligomers characterized by intermolecular β-sheet infrared bands. At a critical oligomer concentration, the emergence of a new FT-IR band allowed to detect fibril formation. A different intermolecular β-sheet interaction of the peptides in oligomers and in fibrils is, therefore, detected by FT-IR spectroscopy, which, in addition, suggests a parallel orientation of the cross β-sheet structures of PrP82-146 fibrils. By AFM, a wide distribution of PrP82-146 oligomer volumes—the smallest ones containing from 5 to 30 peptides—was observed. Interestingly, the statistical analysis of AFM data enabled us to detect a quantization in the oligomer height values differing by steps of ∼ 0.5 nm that could reflect an orientation of oligomer β-strands parallel with the sample surface. Different morphologies were also detected for fibrils that displayed high heterogeneity in their twisting periodicity and a complex hierarchical assembly.Thermal aggregation of PrP82-146 was also investigated by FT-IR spectroscopy, which indicated for these aggregates an intermolecular β-sheet interaction different from that observed for oligomers and fibrils. Unexpectedly, random aggregates, induced by solvent evaporation, were found to display a significant α-helical structure as well as several β-sheet components.All these results clearly point to a high plasticity of the PrP82-146 peptide, which was found to be capable of undergoing several aggregation pathways, with end products displaying different secondary structures and intermolecular interactions.     

A novel mutation in the mitochondrial tRNAAla gene (m.5636T>C) in a patient with progressive external ophthalmoplegia

We report a heteroplasmic novel mutation m.5636T>C in the mt-tRNA^Ala in a patient with bilateral ptosis and ophthalmoparesis in whom a muscle biopsy showed cytochrome c oxdidase (COX) negative and ragged red fibers. Using laser capture microdissection we have isolated COX negative fibers and COX positive fibers from the muscle of the patient and determined that the mutation load was clearly increased in COX negative muscle fibers. Additionally, the mutated m.5636T nucleotide is conserved in all the mammal and non-mammal species analyzed and might be structurally relevant as it is located in a position involved in the formation of tertiary structure of canonical mitochondrial tRNAs.     

Analysis of the MMP-dependent and independent functions of tissue inhibitor of metalloproteinase-2 on the invasiveness of breast cancer cells

Matrix metalloproteinases (MMPs) are secreted endopeptidases that play an essential role in remodeling the extracellular matrix (ECM). MMPs are primarily active during development, when the majority of ECM remodeling events occurs. In adults, elevated MMP activity has been observed in many pathological conditions such as cancer and osteoarthritis. The proteolytic activity of MMPs is controlled by their natural inhibitors - the tissue inhibitor of metalloproteinases (TIMPs). In addition to blocking MMP-mediated proteolysis, TIMPs have a number of MMP-independent functions including binding to cell surface proteins thereby stimulating signaling cascades. TIMP-2, the most studied member of the family, can both inhibit and activate MMPs directly, as well as inhibit MMP activity indirectly by upregulating expression of RECK, a membrane anchored MMP regulator. While TIMP-2 has been shown to play important roles in breast cancer, we describe how the MMP-independent effects of TIMP-2 can modulate the invasiveness of MCF-7, T47D and MDA-MB-231 breast cancer cells. Using an ALA + TIMP-2 mutant which is devoid of MMP inhibition, but still capable of initiating specific cell signaling cascades, we show that TIMP-2 can differentially affect MMP activity and cellular invasiveness in both an MMP dependent and independent manner. More specifically, MMP activity and invasiveness is increased with the addition of exogenous TIMP-2 in poorly invasive cell lines whereas it is decreased in highly invasive cells lines (MDA-MB-231). Conversely, the addition of ALA + TIMP-2 resulted in decreased invasiveness regardless of cell line.