Concurrent Conditions in Patients with Chronic Constipation: A Population–Based Study

Background

Chronic constipation (CC) is a common condition but its concurrent conditions are not well characterized. We measured the prevalence and risk of developing 15 pre–specified concurrent conditions in patients with CC.

Methods

Retrospective cohort study using the Medicaid database of California, utilizing ICD-9 codes for detection of cases (CC), controls (patients with GERD) and concurrent conditions. Study period was 01/01/1995 to 06/30/2005. Index date was the date 3 months before the first physician visit for CC. Pre-index time (12 months) was compared to post-index time (12 months) to assess the association of every concurrent condition within each cohort. To account for ascertainment bias, an adjusted odds ratio was calculated by comparing the odds ratio for every concurrent condition in the CC cohort to that in the GERD cohort.

Results

147,595 patients with CC (mean age 54.2 years; 69.7% women; 36.2% white) and 142,086 patients with GERD (mean age 56.3 years; 65.3% women; 41.6% white) were evaluated. The most prevalent concurrent conditions with CC were hemorrhoids (7.6%), diverticular disease (5.9%), ano–rectal hemorrhage (4.7%), irritable bowel syndrome (3.5%) and fecal impaction (2%). When adjusted for ascertainment bias, the most notable associations with CC were Hirschsprung''s disease, fecal impaction and ano-rectal conditions such as fissure, fistula, hemorrhage and ulcers.

Conclusion

Chronic constipation is associated with several concurrent conditions of variable risk and prevalence. To reduce the overall burden of CC, these concurrent conditions need to be addressed.     

Development of METAL‐ACTIVE SITE and ZINCCLUSTER tool to predict active site pockets

The advent of whole genome sequencing leads to increasing number of proteins with known amino acid sequences. Despite many efforts, the number of proteins with resolved three dimensional structures is still low. One of the challenging tasks the structural biologists face is the prediction of the interaction of metal ion with any protein for which the structure is unknown. Based on the information available in Protein Data Bank, a site (METALACTIVE INTERACTION) has been generated which displays information for significant high preferential and low‐preferential combination of endogenous ligands for 49 metal ions. User can also gain information about the residues present in the first and second coordination sphere as it plays a major role in maintaining the structure and function of metalloproteins in biological system. In this paper, a novel computational tool (ZINCCLUSTER) is developed, which can predict the zinc metal binding sites of proteins even if only the primary sequence is known. The purpose of this tool is to predict the active site cluster of an uncharacterized protein based on its primary sequence or a 3D structure. The tool can predict amino acids interacting with a metal or vice versa. This tool is based on the occurrence of significant triplets and it is tested to have higher prediction accuracy when compared to that of other available techniques.     

Investigation of anti-inflammatory and toxicity effects of mangrove-derived Streptomyces rochei strain VITGAP173

Mangrove ecosystems generate the major biodiversity hotspots of actinobacteria. Among the actinobacteria, Streptomyces species are the prolific producers of bioactive natural products. In this study, with research efforts to discover biopotential compounds from marine actinobacteria, 41 actinobacterial strains were isolated from sediment soil sample of Indian mangrove regions. The phylogeny prediction using the 16S rRNA gene sequences revealed that the isolates were related to Streptomyces. Isolates were further screened based on a two-step process wherein the first step, around nine strains, unveiled the presence of type 1 polyketide synthase gene and dTDP-glucose 4,6-dehydratase gene through polymerase chain reaction. As the second step of the screening process, cell viability assay was performed in RAW264.7 cells to assess the toxicity of extracts. Among all the isolates, Streptomyces rochei strain VITGAP173 was subjected to further analysis. To explore the bioactivities, the organic solvent extraction method was utilized to extract the broth culture of VITGAP173. Inhibition of nitric oxide and cyclooxygenase enzymes upon lipopolysaccharide-induced inflammation were utilized to evaluate the anti-inflammatory efficacy, and the results showed the potency of VITGAP173 in a dose-dependent manner. The extract significantly suppressed the messenger RNA levels of the inflammatory mediators such as tumor necrosis factor-α and interleukin-6 induced by lipopolysaccharide in RAW264.7 macrophages. The presence of several chemical constituents was identified through gas chromatography-mass spectrometry analysis of VITGAP173 extract. To achieve the toxicity analysis, oral administration of VITGAP173 extract in Wistar albino rats was carried out to investigate the biochemical parameters, histopathology which revealed its nontoxic nature.     

The bacterial virulence factor NleA inhibits cellular protein secretion by disrupting mammalian COPII function

Enterohemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC) maintain an extracellular lifestyle and use a type III secretion system to translocate effector proteins into the host cytosol. These effectors manipulate host pathways to favor bacterial replication and survival. NleA is an EHEC/EPEC- and related species-specific translocated effector protein that is essential for bacterial virulence. However, the mechanism by which NleA impacts virulence remains undetermined. Here we demonstrate that NleA compromises the Sec23/24 complex, a component of the mammalian COPII protein coat that shapes intracellular protein transport vesicles, by directly binding Sec24. Expression of an NleA-GFP fusion protein reduces the efficiency of cellular secretion by 50%, and secretion is inhibited in EPEC-infected cells. Direct biochemical experiments show that NleA inhibits COPII-dependent protein export from the endoplasmic reticulum. Collectively, these findings indicate that disruption of COPII function in host cells contributes to the virulence of EPEC and EHEC.     

The C-terminal helix in the YjeQ zinc-finger domain catalyzes the release of RbfA during 30S ribosome subunit assembly

YjeQ (also called RsgA) and RbfA proteins in Escherichia coli bind to immature 30S ribosome subunits at late stages of assembly to assist folding of the decoding center. A key step for the subunit to enter the pool of actively translating ribosomes is the release of these factors. YjeQ promotes dissociation of RbfA during the final stages of maturation; however, the mechanism implementing this functional interplay has not been elucidated. YjeQ features an amino-terminal oligonucleotide/oligosaccharide binding domain, a central GTPase module and a carboxy-terminal zinc-finger domain. We found that the zinc-finger domain is comprised of two functional motifs: the region coordinating the zinc ion and a carboxy-terminal α-helix. The first motif is essential for the anchoring of YjeQ to the 30S subunit and the carboxy-terminal α-helix facilitates the removal of RbfA once the 30S subunit reaches the mature state. Furthermore, the ability of the mature 30S subunit to stimulate YjeQ GTPase activity also depends on the carboxy-terminal α-helix. Our data are consistent with a model in which YjeQ uses this carboxy-terminal α-helix as a sensor to gauge the conformation of helix 44, an essential motif of the decoding center. According to this model, the mature conformation of helix 44 is sensed by the carboxy-terminal α-helix, which in turn stimulates the YjeQ GTPase activity. Hydrolysis of GTP is believed to assist the release of YjeQ from the mature 30S subunit through a still uncharacterized mechanism. These results identify the structural determinants in YjeQ that implement the functional interplay with RbfA.     

Biosorption of Chromium,Copper, and Nickel Ions by Tamarindus Indica Fruit Nut Testa

Biosorption of chromium, copper, and nickel from aqueous solution by Tamarindus indica fruit nut testa (TFNT) in its pristine and acid-treated forms was studied under equilibrium and column-flow conditions. TFNT, a tannin-containing material, was characterized by energy dispersion x-ray fluorescence (EDXRF) and Fourier transform infrared (FTIR) spectral techniques and surface analysis. The effect of experimental variable parameters such as pH, concentration of metal ions, amount of adsorbent, and contact time on adsorption was investigated. Batch isothermal equilibrium data were analyzed on the basis of Langmuir and Freundlich adsorption isotherms. The kinetics of the adsorption process were studied in terms of Lagergren first-order kinetic model. The monolayer adsorption capacities of pristine and acid-treated forms of tamarind seed coat were found to be 44.8 and 77.5 mg/g for Cr(VI), 55.8 and 99.0 mg/g for Ni(II), and 84.7 and 85.4 mg/g for Cu(II) ions, respectively. The column-flow adsorption data were used to obtain breakthrough curves. The biosorbent loaded with the metal ions was regenerated using 1.0 M HCl and the regenerated bed was used for subsequent adsorption-desorption cycle.     

Characterization of the NleF effector protein from attaching and effacing bacterial pathogens

Enterohemorrhagic Escherichia coli (EHEC) is a water- and food-borne pathogen that causes hemorrhagic colitis. EHEC uses a type III secretion system (T3SS) to translocate effector proteins that subvert host cell function. T3SS-substrates encoded outside of the locus of enterocyte effacement are important to E. coli pathogenesis. We discovered an EHEC secreted protein, NleF, encoded by z6020 in O-island 71 of E. coli EDL933 that we hypothesized to be a T3SS substrate. Experiments are presented that probe the function of NleF and its role in virulence. Immunoblotting of secreted and translocated proteins suggest that NleF is secreted by the T3SS and is translocated into host cells in vitro where it localizes to the host cytoplasm. Infection of HeLa cells with E. coli possessing or lacking nleF and transient expression of NleF-GFP via transfection did not reveal a significant role for NleF in several assays of bacterial adherence, host cytoskeletal remodeling, or host protein secretion. However, competitive coinfection of mice with Citrobacter rodentium strains possessing or lacking nleF suggested a contribution of NleF to bacterial colonization. Challenge of gnotobiotic piglets also revealed a role for NleF in colonization of the piglet colon and rectoanal junction.     

Phosphorylated YDXV motifs and Nck SH2/SH3 adaptors act cooperatively to induce actin reorganization

We have analyzed the means by which the Nck family of adaptor proteins couples adhesion proteins to actin reorganization. The nephrin adhesion protein is essential for the formation of actin-based foot processes in glomerular podocytes. The clustering of nephrin induces its tyrosine phosphorylation, Nck recruitment, and sustained localized actin polymerization. Any one of three phosphorylated (p)YDXV motifs on nephrin is sufficient to recruit Nck through its Src homology 2 (SH2) domain and induce localized actin polymerization at these clusters. Similarly, Nck SH3 mutants in which only the second or third SH3 domain is functional can mediate nephrin-induced actin polymerization. However, combining such nephrin and Nck mutants attenuates actin polymerization at nephrin-Nck clusters. We propose that the multiple Nck SH2-binding motifs on nephrin and the multiple SH3 domains of Nck act cooperatively to recruit the high local concentration of effectors at sites of nephrin activation that is required to initiate and maintain actin polymerization in vivo. We also find that YDXV motifs in the Tir protein of enteropathogenic Escherichia coli and nephrin are functionally interchangeable, indicating that Tir reorganizes the actin cytoskeleton by molecular mimicry of nephrin-like signaling. Together, these data identify pYDXV/Nck signaling as a potent and portable mechanism for physiological and pathological actin regulation.     

Tissue localization and partial characterization of pheromone biosynthesis activating neuropeptide inAchaea janata

Female sex pheromone production in certain moth species have been shown to be regulated by a cephalic endocrine peptidic factor: pheromone biosynthesis activating neuropeptide (PBAN), having 33 amino acid residues. Antisera against syntheticHeliothis zea-PBAN were developed. Using these polyclonals, immunoreactivity was mapped in the nervous system ofAchaea janata. Three distinct groups of immunopositive secretory neurons were identified in the suboesophageal ganglion; and immunoreactivity was observed in the corpora cardiaca, thoracic and in the abdominal ganglia. From about 6000 brain sub-oesophageal ganglion complexes, the neuropeptide was isolated; and purified sequentially by Sep-pak and reversed phase high performance liquid chromatographic methods. Identity of purified PBAN fraction was confirmed with polyclonal antibody by immunoblotting. Molecular mass of the isolated peptide was determined by matrix-assisted laser desorption/ionization mass spectrometry, and was found to be 3900 Da, same as that of knownH. zea-PBAN. Radiochemical bioassay confirmed the pheromonotropic effect of the isolated neuropeptide in this insect