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991.
Objective: The objective was to examine the circadian changes in blood pressure and their relation to the metabolic syndrome and its components in Omani Arabs. Research Methods and Procedures: Ambulatory blood pressure (ABPM) was recorded in 1124 subjects from 5 large, extended, consanguineous, and young Arab pedigrees. According to the International Diabetes Federation's definition, 264 subjects had the metabolic syndrome, a prevalence of 23%. Subjects were defined as non‐dippers when their nocturnal systolic blood pressure (SBP) fell by <10% from daytime SBP. Results: Non‐dippers with the metabolic syndrome were 131 of 264 (50%), compared with 265 of 860 (31%) without the metabolic syndrome. Of the non‐dippers, 99 of 131 (76%) were females and 32 of 131 (24%) were males. Daytime and nighttime SBP and DBP and nighttime pulse pressure were significantly higher in non‐dipper subjects with the metabolic syndrome. The important determinants of a non‐dipping BP in this cohort were high BMI and high serum triglycerides. Discussion: We hypothesize that obesity and nocturnal volume‐dependent hypertension may be involved in the pathophysiology of non‐dipping in the metabolic syndrome. This study showed that non‐dipping BP was common in subjects with the metabolic syndrome. Higher 24‐hour blood pressure load may add to the indices of the overall cardiovascular burden already associated with the metabolic syndrome.  相似文献   
992.
This article introduces a new approach for the construction of a risk model for the prediction of Traumatic Brain Injury (TBI) as a result of a car crash. The probability of TBI is assessed through the fusion of an experiment-based logistic regression risk model and a finite element (FE) simulation-based risk model. The proposed approach uses a multilevel framework which includes FE simulations of vehicle crashes with dummy and FE simulations of the human brain. The loading conditions derived from the crash simulations are transferred to the brain model thus allowing the calculation of injury metrics such as the Cumulative Strain Damage Measure (CSDM). The framework is used to propagate uncertainties and obtain probabilities of TBI based on the CSDM injury metric. The risk model from FE simulations is constructed from a support vector machine classifier, adaptive sampling, and Monte-Carlo simulations. An approach to compute the total probability of TBI, which combines the FE-based risk assessment as well as the risk prediction from the experiment-based logistic regression model is proposed. In contrast to previous published work, the proposed methodology includes the uncertainty of explicit parameters such as impact conditions (e.g., velocity, impact angle), and material properties of the brain model. This risk model can provide, for instance, the probability of TBI for a given assumed crash impact velocity.  相似文献   
993.
International Journal of Peptide Research and Therapeutics - One of the main problems in tumor therapy is immunosuppressive microenvironment of the tumor. To overcome this, we assessed targeted...  相似文献   
994.
995.
This paper reports a comparative study of four kinetic models that can be applied in the design of subsurface horizontal flow reed beds for wastewater treatment. The models were developed from different combinations of Monod kinetics, first-order kinetics, continuous stirred-tank reactor and plug flow patterns. Using three statistical parameters (coefficient of determination, relative root mean square error, and model efficiency), critical examinations were made on the accuracy of these models. For predicting organic matter removal, the combination of Monod kinetics with plug flow pattern gave the closest match between theoretical predictions and actual performances of 80 horizontal flow reed beds. In all four models, the coefficients of BOD removal were found to increase slightly with BOD loading. The ratios of BOD/COD had no correlation with the coefficients, indicating that in the horizontal flow reed beds the degradation of organic matter is insensitive to the nature of organics in the wastewater.  相似文献   
996.
In a screening program for isolation of thermophilic lipase-producing bacteria, a number of thermophilic bacteria were isolated from desert soil from Baltim, Egypt. Among 55 isolates, a potent bacterial candidate (starin-5) was characterized and identified by biochemical and PCR techniques, based on 16S rRNA sequencing. Phylogenetic analysis revealed its closeness to geobacilli especially the thermophilic Geobacillus stearothermophilus with optimal growth and lipolytic enzyme activity at 60°C and pH 7.0. An inducible nature of lipolytic enzyme synthesis using glycerol and glucose was demonstrated. Approximately, 94–100% of the original activity was retained due to thermal stability of the crude enzyme after heat treatment for 15 min at 30–60°C. The enzyme retained 84.84% of its original activity during incubation at 70°C (pH 8.0) for 15 min. Lipase enzyme from G. stearothermophilus strain-5 was immobilized on various carriers and the most suitable carrier was chitin that showed 73.03% of activity yield.  相似文献   
997.
The gene for the Salmonella enterica serovar Enteritidis fimbrial protein SefA was cloned into an Escherichia coli surface expression vector and confirmed by Western blot assay. E. coli clones expressing SefA attached to avian ovary granulosa cells and HEp-2 cells, providing evidence for the involvement of SefA in the ability of Salmonella to attach to eukaryotic cells.During the 1980s to 1990s, the worldwide increase in human Salmonella enterica serovar Enteritidis infections was associated with the consumption of contaminated eggs and egg products (13, 26, 28). In the United States, grade A shell eggs were identified as a major source contributing to Salmonella infections (19, 26, 29), and the percentage of S. Enteritidis among all Salmonella isolated from outbreaks increased from 5% to 26% from 1976 to 1996 (4). Although outbreak-associated cases due to S. Enteritidis decreased from 974 during 1998 to 2000 to 692 cases in 2004 to 2006, the 28 outbreaks in 2006 still remained above the Healthy People 2010 target of 22 (6). Despite efforts directed at reducing egg-related outbreaks, S. Enteritidis infections are still among those with the highest incidence of the seven most-reported serotypes of Salmonella (5).The large proportion of S. Enteritidis serotypes involved in food-borne outbreaks is partly attributed to the adherence elicited by surface fimbriae. Fimbriae are nonflagellar filamentous surface appendages which consist of helically arranged repeating subunit proteins called fimbrins (24). Four serologically distinct fimbriae of S. Enteritidis have been characterized according to their size (kDa) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels: SEF21, SEF18, SEF17, and SEF14 (9-11, 21). Fimbriae can mediate the aggregation of bacteria and their attachment to inert surfaces (2) and to the surfaces of eukaryotic cells, especially to carbohydrate receptors (8, 11, 36).SEF14 fimbriae are detected in all S. Enteritidis strains and are not widely distributed among the Enterobacteriaceae (10). These fimbriae consist of a repeating major subunit protein of 14.3 kDa (SefA) encoded by the gene sefA (9, 33). The results of studies by Peralta et al. (25) and Thiagarajan et al. (31) indicate that SEF14 fimbriae may have a role in pathogenesis by mediating attachment to eukaryotic cells. We focused on SEF14 fimbriae because of their limited distribution and their role as a main immunological target in the serological response to infection by S. Enteritidis in chickens (12). The objectives of this study were to clone and investigate the functional properties of the SEF14 fimbrin, SefA, as part of a fusion protein in Escherichia coli and to determine whether it could mediate adherence to tissue culture cells in vitro.Bacterial strains, tissue culture cells, and plasmids used in this study are described in Table Table1.1. Bacterial cultures were grown in LB medium (Fisher Scientific, Raleigh, NC) supplemented with 0.2% glucose and shaken at 220 revolutions min−1 or in colonization factor broth (30) at 37°C. Chloramphenicol (Cm; 10 μg ml−1) and ampicillin (Amp; 50 μg ml−1) were added as needed (Sigma-Aldrich, St. Louis, MO). Avian ovary granulosa cells were grown in 5% CO2 atmosphere at 37°C in M199 medium supplemented with 26 mM NaHCO3, 0.1% bovine serum albumin, 100 U ml−1 penicillin G, and 100 μg ml−1 streptomycin sulfate (Gibco-BRL, Gaithersburg, MD). HEp-2 cells were obtained from ATCC (Rockville, MD) and grown in 5% CO2 atmosphere at 37°C in minimum essential medium (Sigma-Aldrich), pH 7.2, supplemented with 26 mM NaHCO3, 7% fetal bovine serum, 100 U ml−1 penicillin G, and 100 μg ml−1 streptomycin sulfate (Gibco-BRL and Sigma-Aldrich).

TABLE 1.

Bacterial strains, tissue culture cells, and plasmids
Bacterial strain, tissue culture cell line, or plasmidRelevant characteristicsSource or reference
Strains
    S. Enteritidis CDC9Phage type 8, SEF14+sefA+A. M. Saeed
    E. coli JM109endA1 recA1 gyrA96 thi hsdR17 (rK mK+) mcrB+ relA1 supE44 λ Δ(lac-proAB) supE44 [F′ traD36 proAB lacIqZΔM15]B. Olwin
Tissue culture cell lines
    HEp-2 cellsEpidermoid carcinoma isolated from human larynxATCC CCL23
    Granulosa cellsIsolated from chicken ovariesA. M. Saeed
Plasmids
    pTX10112.5 kb, Ampr CmrlacIq+lpp-ompA-bla fusion expressed through Plac or PlppG. Georgiou (15)
    pDUG3A11.5 kb, CmrlacIq+lpp-ompA-sefA fusion expressed through Plac or PlppThis study
Open in a separate windowPrimers were designed to amplify the known sefA sequence (35) corresponding to the mature protein and included restriction sites to facilitate directional cloning of the amplified target to replace the β-lactamase gene in pTX101 (27). E. coli JM109 host cells were then transformed by electroporation (Gene Pulser, Bio-Rad Laboratories, Hercules, CA). In prior studies, derivatives of pTX101 have been used successfully to express several proteins on the outer surface of E. coli cells (16, 17). The Lpp portion of pTX101 serves to localize the fusion protein to the outer membrane, while the OmpA portion traverses the outer membrane and directs the product of the cloned gene (i.e., β-lactamase or SefA) to the surface.Membrane fractions were isolated as previously described (7) with the following modifications. Cell suspensions were sonicated with an XL series sonicator (Heat Systems, Farmingdale, NY) at 100 W and then added to ice-cold Tris-Cl, and the remaining bacteria were removed by centrifugation. The total membrane was sedimented by centrifugation (45,000 × g at 4°C) for 1 h and then suspended in Tris-Cl, and the outer membrane was isolated by adding 0.5% (wt/vol) N-lauryl sarcosine (Sigma) and shaking at 200 rpm for 30 min at 22°C to dissolve the inner membrane.Crude SefA was obtained from S. Enteritidis CDC9 as described previously by Feutrier et al. (14). Purified SefA was obtained by the method of Chart (7) with the following modifications. Briefly, crude SefA was run on an SDS-PAGE gel and a portion corresponding to SefA was extracted from gel slices with Z-spin microcentrifuge columns (Pall/Gelman Sciences, Ann Arbor, MI). The purified SefA was vacuum dried and suspended in phosphate-buffered saline buffer.SDS-PAGE was performed according to the method of Laemmli (18), and proteins were visualized with Coomassie blue. An identical gel was prepared for Western blots, and proteins were transferred onto BioTrace polyvinylidene difluoride (Pall/Gelman Sciences). Western blotting was done according to the membrane manufacturer''s instructions (1). SefA monoclonal mouse antibodies 69/25 supplied by C. J. Thorns (Central Veterinary Laboratories, Weybridge, Surrey; 32) were used as the primary antibody; ImmunoPure goat anti-mouse immunoglobulin G(H+L) biotin-conjugated antibodies (Pierce, Rockford, IL) were used as the secondary antibody; and AVIDX-AP, assay buffer (0.1 M diethanolamine, 1.0 mM MgCl2, pH 10.0), I-Block, and CSPD (Applied Biosystems, Bedford, MA) were used in the chemiluminescent detection of the secondary antibodies using X-ray film. SDS-PAGE of total membrane fractions of E. coli JM109(pDUG3A) demonstrated a protein of the expected size for the Lpp-OmpA-SefA fusion protein (∼31 kDa); however, similarly sized proteins were also observed in the control strains [JM109 and JM109(pTX101)] (Fig. (Fig.1A).1A). Western blot analysis confirmed the presence of SefA in the 31-kDa band in the recombinant strain [JM109(pDUG3A)] but not in membrane protein fractions from either the host strain alone (JM109) or the host strain harboring the pTX101 vector (Fig. (Fig.1B).1B). When outer membrane fractions were selectively isolated from the inner membrane, the presence of the 31-kDa SefA fusion protein was more readily detected over the background of proteins of similar size (Fig. (Fig.1C).1C). The data provide further evidence for the localization of the SefA fusion protein in the outer membrane of E. coli JM109(pDUG3A).Open in a separate windowFIG. 1.SDS-PAGE and Western blot of SefA samples using SefA monoclonal antibodies. (A) SDS-PAGE of total membrane fractions collected from cells grown at 37°C. (B) Western blot of SDS-PAGE gel shown in panel A using monoclonal mouse antibodies 69/25 as an immunoprobe for SefA. (C) SDS-PAGE of outer membrane fractions collected from cells grown at 25°C. Lanes: 1, molecular mass standards (99.4, 66.2, 45, 31, 21.5, and 14.4 kDa); 2, crude SefA; 3, purified SefA; 4, E. coli JM109; 5, E. coli JM109(pTX101); 6, E. coli JM109(pDUG3A). Arrows indicate Lpp-OmpA-SefA fusion protein at ∼31 kDa.Attachment assays on avian ovary granulosa and HEp-2 cells were done according to the method of Thiagarajan et al. (30), with some modifications. Briefly, granulosa cells were seeded and grown as a monolayer on sterile coverslips and then washed three times with M199 medium (Gibco), and 1 × 107 CFU of bacterial cells (grown with and without 1% d-mannose) was added to the coverslips. The coverslips were then incubated in a 5% CO2 atmosphere at 37°C for 3 h, after which the cells were washed five times with M199 medium, fixed with methanol, stained with 10% Giemsa stain (Sigma), and examined by light microscopy. Attachment assays with HEp-2 cells were done as described above except that minimum essential medium (Sigma) was used as the wash solution.Peralta et al. (25) showed that in vitro attachment of S. Enteritidis to murine intestinal epithelial cells was reduced by SefA antibodies, suggesting a role for SefA in attachment. Thiagarajan et al. (30) demonstrated attachment of S. Enteritidis to avian ovary granulosa cells that form one of the layers surrounding the yolk in a preovulatory follicle. They suggest that this attachment may be a mechanism precipitating S. Enteritidis infection of hens'' ovaries that may subsequently lead to transovarian transmission to shell eggs. In our study, we compared the attachment of S. Enteritidis CDC9, E. coli JM109(pDUG3A) (sefA clone), and JM109(pTX101) (vector) to both avian granulosa (Fig. (Fig.2)2) and HEp-2 cells (Fig. (Fig.3).3). S. Enteritidis CDC9 demonstrated a mannose-resistant pattern of attachment to both granulosa and HEp-2 cells (Fig. (Fig.2A2A and and3A)3A) while JM109(pTX101) did not attach to these cell lines (Fig. (Fig.2B2B and and3B).3B). However, JM109(pDUG3A), expressing the SefA fusion protein, demonstrated mannose-sensitive attachment to both granulosa and HEp-2 cells, indicating attachment to eukaryotic cell lines attributed to the presence of SefA (Fig. (Fig.2C2C and and3C3C).Open in a separate windowFIG. 2.Attachment of indicated bacterial cells to avian ovary granulosa cells: S. Enteritidis CDC9 (A), E. coli JM109(pTX101) (B), and E. coli JM109(pDUG3A) (C). Cells were stained with 10% Giemsa stain and photographed with a light microscope at ×400 magnification.Open in a separate windowFIG. 3.Attachment of indicated bacterial cells to HEp-2 cells: S. Enteritidis CDC9 (A), E. coli JM109(pTX101) (B), and E. coli JM109(pDUG3A) (C). Cells were stained with 10% Giemsa stain and photographed with a light microscope at ×400 magnification.Thorns (34) reported that both a wild-type S. Enteritidis strain and a sefA mutant were able to attach to HEp-2 cells, indicating that multiple determinants may mediate attachment. This is also indicated by differences in mannose sensitivities of various S. Enteritidis strains (30). The results of the Western blot and cell culture attachment assays suggest that the mannose-sensitive binding of JM109(pDUG3A) is due to the presence of SefA in the outer membrane, since JM109(pTX101) did not possess SefA or show attachment. The data also indicate that the presentation of SefA in a fimbrial structure may not be necessary for binding since nonfimbrial adhesions have been reported to mediate attachment to eukaryotic cells (22). Unfolded SefA protein in the Lpp-OmpA-SefA fusion protein may possibly allow hydrophilic or hydrophobic interactions with granulosa or HEp-2 cells, providing for mannose-sensitive adherence.The data presented herein demonstrate that surface-expressed SefA protein may provide to nonadherent bacteria the property of adherence to eukaryotic cells and constitute further evidence for the involvement of SEF14 fimbriae in binding by S. Enteritidis. Heterologously expressed recombinant fimbrial antigens have been used successfully to induce immune responses in mice and pigs (3, 20). The results of previous studies have indicated that purified SefA protein is highly immunogenic and that SefA antibodies increase the survival rate of mice after challenge with S. Enteritidis from 32% in control mice to 78% in vaccinated mice (23, 25). The data warrant further studies to demonstrate whether the attachment observed in vitro could be demonstrated in vivo for possible applications in the competitive exclusion or induction of an immune response using this vector.  相似文献   
998.
999.
Neuropathologic and genetics studies as well as transgenic animal models have provided strong evidence linking misfolding and aggregation of α-synuclein to the progression of Parkinson disease (PD) and other related disorders. A growing body of evidence implicates various oligomeric forms of α-synuclein as the toxic species responsible for neurodegeneration and neuronal cell death. Although numerous different oligomeric forms of α-synuclein have been identified in vitro, it is not known which forms are involved in PD or how, when, and where different forms contribute to the progression of PD. Reagents that can interact with specific aggregate forms of α-synuclein would be very useful not only as tools to study how different aggregate forms affect cell function, but also as potential diagnostic and therapeutic agents for PD. Here we show that a single chain antibody fragment (syn-10H scFv) isolated from a phage display antibody library binds to a larger, later stage oligomeric form of α-synuclein than a previously reported oligomeric specific scFv isolated in our laboratory. The scFv described here inhibits aggregation of α-synuclein in vitro, blocks extracellular α-synuclein-induced toxicity in both undifferentiated and differentiated human neuroblastoma cell lines (SH-SY5Y), and specifically recognizes naturally occurring aggregates in PD but not in healthy human brain tissue.Parkinson disease (PD)2 is the second most common neurodegenerative disorder of the elderly, affecting more than 500,000 people in the United States (1), with 50,000 new cases reported each year at an annual cost estimated at 10 billion dollars per year. Pathologically, PD is characterized by the progressive loss of dopaminergic neurons in the substantia nigra and formation of fibrillar cytoplasmic inclusions known as Lewy bodies and Lewy neurites (2, 3). The protein α-synuclein has been strongly linked to PD (4, 5) and other related neurodegenerative disorders (6, 7) by several lines of evidence. 1) It is the major component of the hallmark Lewy body aggregates associated with PD. 2) Mutations (A53T, A30P, and E46K, where A30P is human A30P α-synuclein; A53T is human A53T α-synuclein; E46K is human E46K α-synuclein) or multiplication in the α-synuclein gene have been linked to familial PD (810). 3) Overexpression of α-synuclein in transgenic mice and Drosophila has been shown to induce the formation of PD-like pathological phenotypes and behavior, although the animal models do not in general replicate neuronal loss patterns (11, 12).α-Synuclein is a small protein (14 kDa) expressed mainly in brain tissues and is primarily localized at the presynaptic terminals of neurons (13). The primary structure of α-synuclein consists of three distinct regions. The N-terminal region of α-synuclein includes the mutation sites associated with familial PD (A53T, A30P, and E46K) and contains six imperfectly conserved repeats (KTKEGV) that may facilitate protein-protein binding. This repeat section is predicted to form amphipathic α-helices, typical of the lipid-binding domain of apolipoproteins (14). The central region, non-amyloid component, is extremely hydrophobic and includes a 12-residue stretch (VTGVTAVAQKTV) that is essential for aggregation (15). The C-terminal region is enriched with acidic glutamate and aspartate residues and is responsible for the chaperone function of α-synuclein (16).α-Synuclein normally exists as an unfolded protein, but it can adopt several different folded conformations depending on the environment, including small aggregates or oligomers, spherical and linear protofibrils, as well as the fibrillar structure found in Lewy bodies (14, 15). A growing body of evidence implicates the oligomeric forms of α-synuclein as the toxic species responsible for neurodegeneration and neuronal cell death (1618). Several different oligomeric forms of α-synuclein including spherical, annular (19), pore-like (20), and dopamine-stabilized structures have been identified in vitro (21).α-Synuclein is considered a cytosolic protein, and consequently its pathogenic effect was assumed to be limited to the cytoplasm of single cells. However, recent studies have suggested that α-synuclein also has extracellular pathogenic effects (2225). α-Synuclein was detected in blood plasma and cerebrospinal fluid in both monomeric and oligomeric forms (2225), and the presence of significantly elevated levels of oligomeric species of α-synuclein has been reported extracellularly in plasma and cerebrospinal fluid samples from patients with PD (23). Furthermore, various studies have shown that aggregated α-synuclein added extracellularly to the culture medium is cytotoxic (2632).Despite all these studies, it is still not clear how the various aggregate forms of α-synuclein are involved in the progression of PD. Therefore, reagents that can interact with specific aggregate forms of α-synuclein would be very useful not only for fundamental studies of how α-synuclein aggregates affect cell function but also as potential diagnostic and therapeutic agents for PD.Recently, we reported inhibition of both aggregation and extracellular toxicity of α-synuclein in vitro by a single chain variable domain antibody fragment (scFv) that specifically recognized an oligomeric form of α-synuclein (32). In this study, we describe a second scFv (syn-10H) that binds a larger later stage oligomeric form of α-synuclein than the previously reported scFv. The syn-10H scFv neutralizes α-synuclein-induced toxicity in both undifferentiated and differentiated SH-SY5Y human neuroblastoma cell line and inhibits α-synuclein aggregation in vitro. The syn-10H scFv reacts specifically with homogenized PD brain tissue but does not cross-react with similarly treated samples taken from Alzheimer disease (AD) or healthy brain samples. Such scFvs therefore have potential value as diagnostic reagents to identify the presence of specific oligomeric species in PD tissue and fluid samples. The scFvs also have value as therapeutic agents as they can be used either extracellularly or expressed intracellularly (intrabodies) to prevent formation of toxic aggregates in vivo whether inside or outside of cells. Intrabodies have been used efficiently to neutralize toxic effects of different pathogenic agents, including α-synuclein (3336). Moreover, immunization studies in mouse models of PD have shown that extracellular antibodies can reduce accumulation of intracellular aggregates of α-synuclein (37), thereby providing precedent for the use of scFvs in potential passive vaccination strategies for treating PD.  相似文献   
1000.
Catechol quinones of estrogens react with DNA by 1,4-Michael addition to form depurinating N3Ade and N7Gua adducts. Loss of these adducts from DNA creates apurinic sites that can generate mutations leading to cancer initiation. We compared the reactions of the catechol quinones of the leukemogenic benzene (CAT-Q) and N-acetyldopamine (NADA-Q) with 2′-deoxyguanosine (dG) or DNA. NADA was used to prevent intramolecular cyclization of dopamine quinone. Reaction of CAT-Q or NADA-Q with dG at pH 4 afforded CAT-4-N7dG or NADA-6-N7dG, which lost deoxyribose with a half-life of 3 h to form CAT-4-N7Gua or 4 h to form NADA-6-N7Gua. When CAT-Q or NADA-Q was reacted with DNA, N3Ade adducts were formed and lost from DNA instantaneously, whereas N7Gua adducts were lost over several hours. The maximum yield of adducts in the reaction of CAT-Q or NADA-Q with DNA at pH 4 to 7 was at pH 4. When tyrosinase-activated CAT or NADA was reacted with DNA at pH 5 to 8, adduct levels were much higher (10- to 15-fold), and the highest yield was at pH 5. Reaction of catechol quinones of natural and synthetic estrogens, benzene, naphthalene, and dopamine with DNA to form depurinating adducts is a common feature that may lead to initiation of cancer or neurodegenerative disease.  相似文献   
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