Antibacterial silver-containing silica glass prepared by ion implantation

Recently, there is much interest in nanocomposites consisting of metal nanoparticles dispersed in dielectric matrix. Silver is the first candidate used in antibacterial research. In the present study, sliver-containing silica glass is prepared by ion implantation. The bactericidal properties of Ag-implanted samples are investigated using E. coli. The implanted samples are characterized by optical absorption spectroscopy, atomic force microscopy and transmission electron microscopy. The size and position of the silver nanoparticles formed by ion implantation can be optimized by adjusting the implanted process parameters. All the implanted samples show antibacterial properties. But the samples with silver nanoparticle-enriched surfaces possess excellent antibacterial properties in comparison with other implanted samples. This indicates that ion implantation is a potential method for synthesizing antibacterial biomaterials.

First measurement of Bose-Einstein correlations in proton-proton collisions at √s=0.9 and 2.36 TeV at the LHC

Bose-Einstein correlations have been measured using samples of proton-proton collisions at 0.9 and 2.36 TeV center-of-mass energies, recorded by the CMS experiment at the CERN Large Hadron Collider. The signal is observed in the form of an enhancement of pairs of same-sign charged particles with small relative four-momentum. The size of the correlated particle emission region is seen to increase significantly with the particle multiplicity of the event.

Transverse-momentum and pseudorapidity distributions of charged hadrons in pp collisions at square root of s = 7 TeV

Charged-hadron transverse-momentum and pseudorapidity distributions in proton-proton collisions at square root of s = 7  TeV are measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield is obtained by counting the number of reconstructed hits, hit pairs, and fully reconstructed charged-particle tracks. The combination of the three methods gives a charged-particle multiplicity per unit of pseudorapidity dN(ch)/dη|(|η|<0.5) = 5.78 ± 0.01(stat) ± 0.23(syst) for non-single-diffractive events, higher than predicted by commonly used models. The relative increase in charged-particle multiplicity from square root of s = 0.9 to 7 TeV is [66.1 ± 1.0(stat) ± 4.2(syst)]%. The mean transverse momentum is measured to be 0.545 ± 0.005(stat) ± 0.015(syst)  GeV/c. The results are compared with similar measurements at lower energies.

Formation of Fatty Acid-degrading, anaerobic granules by defined species

An endospore-forming, butyrate-degrading bacterium (strain BH) was grown on butyrate in monoxenic coculture with a methanogen. The culture formed dense aggregates when Methanobacterium formicicum was the methanogenic partner, but the culture was turbid when Methanospirillum hungatei was the partner. In contrast, a propionate-degrading, lemon-shaped bacterium (strain PT) did not form aggregates with Methanobacterium formicicum unless an acetate-degrading Methanosaeta sp. was also included in the culture. Fatty acid-degrading methanogenic granules were formed in a laboratory-scale upflow reactor at 35(deg)C fed with a medium containing a mixture of acetate, propionate, and butyrate by using defined cultures of Methanobacterium formicicum T1N, Methanosaeta sp. strain M7, Methanosarcina mazei T18, propionate-degrading strain PT, and butyrate-degrading strain BH. The maximum substrate conversion rates of these granules for acetate, propionate, and butyrate were 43, 9, and 17 mmol/g (dry weight)/day, respectively. The average size of the granules was about 1 mm. Electron microscopic observation of the granules revealed that the cells of Methanobacterium formicicum, Methanosaeta sp., butyrate-degrading, and propionate-degrading bacteria were dispersed in the granules. Methanosarcina mazei existed inside the granules as aggregates of its own cells, which were associated with the bulk of the granules. The interaction of different species in aggregate formation and granule formation is discussed in relation to polymer formation of the cell surface.

Composition and role of extracellular polymers in methanogenic granules

Methanobacterium formicicum and Methanosarcina mazeii are two prevalent species isolated from an anaerobic granular consortium grown on a fatty acid mixture. The extracellular polysaccharides (EPS) were extracted from Methanobacterium formicicum and Methanosarcina mazeii and from the methanogenic granules to examine their role in granular development. The EPS made up approximately 20 to 14% of the extracellular polymer extracted from the granules, Methanobacterium formicicum, and Methanosarcina mazeii. The EPS produced by Methanobacterium formicicum was composed mainly of rhamnose, mannose, galactose, glucose, and amino sugars, while that produced by Methanosarcina mazeii contained ribose, galactose, glucose, and glucosamine. The same sugars were also present in the EPS produced by the granules. These results indicate that the two methanogens, especially Methanobacterium formicicum, contributed significantly to the production of the extracellular polymer of the anaerobic granules. Growth temperature, substrates (formate and H(inf2)-CO(inf2)), and the key nutrients (nitrogen and phosphate concentrations) affected polymer production by Methanobacterium formicicum.

Synthesis and Magnetic Properties of Maghemite (gamma-Fe(2)O(3)) Short-Nanotubes

We report a rational synthesis of maghemite (gamma-Fe(2)O(3)) short-nanotubes (SNTs) by a convenient hydrothermal method and subsequent annealing process. The structure, shape, and magnetic properties of the SNTs were investigated. Room-temperature and low-temperature magnetic measurements show that the as-fabricated gamma-Fe(2)O(3) SNTs are ferromagnetic, and its coercivity is nonzero when the temperature above blocking temperature (T(B)). The hysteresis loop was operated to show that the magnetic properties of gamma-Fe(2)O(3) SNTs are strongly influenced by the morphology of the crystal. The unique magnetic behaviors were interpreted by the competition of the demagnetization energy of quasi-one-dimensional nanostructures and the magnetocrystalline anisotropy energy of particles in SNTs.

The molecular characteristics of cefepime-susceptible Escherichia coli and Klebsiella spp. isolates with a positive β-lactamase screening test result but negative confirmation

A negative extended-spectrum β-lactamase (ESBL) phenotypic confirmation test result obtained after a positive ESBL screening test result but which was cefepime-susceptible (NCPSCS) using the Clinical and Laboratory Standards Institute (CLSI) methods has been observed among isolates of Escherichia coli and Klebsiella spp. in the antimicrobial surveillance program in Shanghai, China. Among isolates collected from Huashan Hospital in 2005, NCPSCS strains were observed in 2.5% of 433 E. coli isolates and in 1.2% of 562 Klebsiella spp. isolates. We then selected 11 E. coli isolates and seven Klebsiella spp. NCPSCS isolates. Transmission electron microscopy (TEM), SHV, plasmid-borne AmpC, and CTX-M type ESBL genes were detected by the polymerase chain reaction (PCR) method. We found that all except two K. pneumoniae strains of NCPSCS isolates producing ESBL and AmpC harbored a plasmid-borne CMY-2 or DHA-1 type AmpC enzyme. The majority of NCPSCS E. coli and K. pneumoniae strains from Shanghai harbor plasmid-borne AmpC enzyme, and we recommend that, when NCPSCS strains are identified, further work such as the PCR detection of ESBL genes is necessary to determine whether they will produce ESBLs. The ESBL-positive strains should be reported as resistant to cefepime according to the CLSI guidelines.

Elemental composition of imported porcelain-fused-to-metal crowns--a pilot study

OBJECTIVES

To identify any potentially toxic elements in porcelain-fused-to-metal (PFM) crowns and a bridge manufactured in China.

MATERIALS AND METHODS

Eight PFM crowns and part of a bridge were sourced from China for testing. They were given a typical glaze firing cycle prior to scanning electron microscope analysis. Electron dispersive spectroscopic spot and mapping analysis was carried out on the porcelain/metal collar interface areas in order to determine their elemental composition and distribution.

RESULTS

No toxic elements were detected. The alloy used in the crowns was a nickel-chromium base metal, and that in the bridge was a gold-palladium noble alloy. The veneering porcelain was similar to a standard dental veneering porcelain.

CONCLUSIONS

Within the limitations of the testing method and small sample size, no toxic elements were detected.

A colony-to-lawn method for efficient transformation of Escherichia coli

AIMS

To develop a fast, convenient, inexpensive and efficient Escherichia coli transformation method for changing hosts of plasmids, which can also facilitate the selection of positive clones after DNA ligation and transformation.

METHODS AND RESULTS

A single fresh colony from plasmid-containing donor strain is picked up and suspended in 75% ethanol. Cells are pelleted and resuspended in CaCl(2) solution and lysed by repetitive freeze-thaw cycles to obtain plasmid-containing cell lysate. The E. coli recipient cells are scraped from the lawn of LB plate and directly suspended in the plasmid-containing cell lysate for transformation. Additionally, a process based on colony-to-lawn transformation and protein expression was designed and conveniently used to screen positive clones after DNA ligation and transformation.

CONCLUSIONS

With this method, a single colony from plasmid-containing donor strain can be directly used to transform recipient cells scraped from lawn of LB plate. Additionally, in combination with this method, screening of positive clones after DNA ligation and transformation can be convenient and time-saving.

SIGNIFICANCE AND IMPACT OF THE STUDY

Compared with current methods, this procedure saves the steps of plasmid extraction and competent cell preparation. Therefore, the method should be highly valuable especially for high-throughput changing hosts of plasmids during mutant library creation.

D-dimer testing in pregnant patients: towards determining the next 'level' in the diagnosis of deep vein thrombosis

SUMMARY BACKGROUND

The role of D-dimer in excluding deep vein thrombosis (DVT) in pregnancy is currently uncertain. We hypothesized that the specificity of sensitive D-dimer assays could be improved without compromising sensitivity by using higher D-dimer cut-off values.

OBJECTIVE

To determine the test characteristics of two rapid enzyme-linked immunosorbent assays and three latex agglutination assays in pregnancy.

METHOD

We recruited consecutive pregnant women who presented to participating centers with suspected DVT for the study. Symptomatic women were investigated with compression ultrasonography, and received 3 months of clinical follow-up to assess for the presence of venous thrombosis. Plasma samples for D-dimer were collected and frozen at the time of presentation. The median and mean D-dimer values for respective trimesters of pregnancy in patients with and without DVT were calculated. Receiver operating curves (ROCs) were plotted for respective assays to establish the best cut-points. The test characteristics corresponding to standard cut-points and these 'pregnancy' cut-points are presented.

RESULTS

The prevalence of DVT in our cohort was 6.6% (95% confidence interval 4.0-10.6%). The mean and median D-dimer values were significantly increased throughout pregnancy. Overall, women with confirmed DVT had higher D-dimer levels than women without DVT (P < 0.0001). Improved specificities (62-79%) were observed with the use of higher cut-points obtained from ROCs for all five assays, and high sensitivities were maintained (80-100%) for DVT diagnosis.

CONCLUSION

Using higher cut-points than those used in non-pregnant patients, the specificity of D-dimer assays for the diagnosis of DVT in pregnancy can be improved without compromising sensitivity. Validation in prospective management studies is needed.

Prolonged cardiac allograft survival in mouse model after complement depletion with Yunnan cobra venom factor

BACKGROUND

Activation of the complement system is the leading mechanism that causes antibody-mediated acute rejection and hyperacute rejection after xenotransplantation. The major cause of acute rejection in allogeneic transplantation is the T cell-mediated specific immune response. We studied the effects of complement on acute rejection after cardiac allotransplantation using complement depletion with cobra venom factor (CVF) in the mouse.

MATERIALS AND METHODS

The Balb/c-C57 mouse model of heterotopic cardiac allograft was used. The mice were divided into 2 groups, a control group and a CVF-treated group. After intravenous injection of CVF, the experimental group was observed for allograft survival time. Twelve mice from the control and experimental groups were sacrificed on days 3, 5, and 7 after the operation. The pathologic grade of acute rejection, deposition of C3 in tissue, extent of infiltration by CD4+ and CD8+ T cells, and expression of MHC-II, B7-1, and B7-2 were compared between the 2 groups.

RESULTS

In the CVF-treated group, mean (SD) survival of the cardiac allograft was 26.2 (1.7) days, and in the control group was 8.4 (0.4) days (P < .01). Pathologic examination and immunohistochemistry demonstrated that the grade of acute rejection, deposition of C3 in tissue, extent of infiltration of CD4+ and CD8+ T cells, and expression of MHC-II, B7-1, and B7-2 were significantly decreased in the CVF-treated group.

CONCLUSION

Depletion of complement in the serum with CVF inhibits acute cardiac allograft rejection in the mouse.

Measurements of h(c)(1P(1)) in psi' decays

We present measurements of the charmonium state h(c)(1P(1)) made with 106x10(6) psi' events collected by BESIII at BEPCII. Clear signals are observed for psi'-->pi0 h(c) with and without the subsequent radiative decay h(c)-->gamma eta(c). First measurements of the absolute branching ratios B(psi'-->pi0 h(c)) = (8.4+/-1.3+/-1.0) x 10(-4) and B(h(c)-->gamma eta(c)) = (54.3+/-6.7+/-5.2)% are presented. A statistics-limited determination of the previously unmeasured h(c) width leads to an upper limit Gamma(h(c))<1.44 MeV (90% confidence). Measurements of M(h(c)) = 3525.40+/-0.13+/-0.18 MeV/c2 and B(psi'-->pi0 h(c)) x B(h(c)-->gamma eta(c)) = (4.58+/-0.40+/-0.50) x 10(-4) are consistent with previous results.

Clinicopathological Features of Solitary Fibrous Tumours in the Extremities: Four Case Reports and a Literature Review

This paper reports on the clinicopathological features of four patients with solitary fibrous tumours arising from the extremities and presents a review of the relevant literature. The patients consisted of three women and one man, with a mean age of 47.8 years. Standard pre-operative work-up data were examined, including: history, clinical examination, plain radiography, computed tomography scans of the lesion and chest, magnetic resonance imaging, angiography, technetium-99m bone scan, thallium-201 scintigraphy and routine laboratory tests. Immunohisto chemical staining was performed for CD34, Bcl-2 protein, vimentin, S-100 protein, desmin and smooth muscle actin, and pathological material was reviewed for the presence of histologically malignant components. Immunohistochemically, all of the tumours were diffusely positive for CD34. Clinical and radiological findings of solitary fibrous tumours affecting the extremities are reminiscent of those of aggressive or malignant soft tissue tumours. Pathological and immunohistochemical studies are important in making the correct diagnosis.

Evidence for tight junction protein disruption in intestinal mucosa of malignant obstructive jaundice patients

OBJECTIVE

Experimental and clinical studies have shown that obstructive jaundice results in increased intestinal permeability. The mechanisms implicated in this phenomenon remain obscure. Integrated tight junctions (TJs) are essential for normal gut barrier function. TJ proteins, such as zonula occludens (ZO)-1, claudins and occludin, are indispensable to maintain the function of TJs. This study was undertaken to investigate whether TJ protein disruption occurs in the intestinal mucosa of malignant obstructive jaundice (MOJ) patients.

MATERIAL AND METHODS

Three groups were involved: Group A, MOJ patients whose bilirubin level was >or= 43 microM; Group B, MOJ patients without jaundice; and Group C, patients who underwent gastroscopy with negative findings (controls). Biopsy was done in all participants at the second part of the duodenum, distal to the ampulla of Vater. The morphological and ultrastructural changes of intestinal mucosa were observed. The distributions and expressions of the TJ proteins occludin, ZO-1, claudin-1 and claudin-4 in intestinal mucosa were evaluated by immunohistochemistry and Western blotting.

RESULTS

Histological examination showed a mild infiltration of the lamina propria by chronic inflammatory cells in Group A compared with Groups B and C. Duodenal architecture showed that the microvillus of Group A patients was loose, the structures of junctional complexes were disrupted and the gaps between cell junctions were wider. As shown by immunohistochemical staining and Western blotting, greatly reduced expressions of occludin, ZO-1 and claudin-1 protein were detected in Group A, whereas claudin-4 expression was significantly increased.

CONCLUSIONS

TJs in MOJ patients with jaundice were disrupted in the intestinal epithelium, which may have resulted from the alterations in TJ-related protein expression. TJ interruption may be a key factor contributing to intestinal mucosal barrier injury and increased intestinal permeability.

Synthesis and pharmacological effects of new, N-substituted soft anticholinergics based on glycopyrrolate

To reduce the possibility of systemic side-effects in locally administered anticholinergics, two new N-substituted glycopyrrolate analogues designed using soft drug design approaches have been synthesized and evaluated in vitro and in vivo. Because stereospecificity is known to be important at muscarinic receptors, the new compounds SGM and SGE also have been prepared as their pure 2R isomers, 2R-SGM and 2R-SGE, by starting from optically pure (-)-cyclopentylmandelic acid, and the corresponding isomers were indeed found to be more active. The new soft glycopyrrolates were chemically more stable under acidic conditions, and the ethyl esters SGE were more stable than the methyl esters SGM. The new compounds were also found to be quite susceptible to extrahepatic metabolism, having half-lives of 20–30 min in rat plasma (in vitro), consistent with their soft nature. Binding studies at human muscarinic receptors (M1−M4) and guinea-pig ileum assays found 2R-SGM and 2R-SGE to have potencies somewhat less than, but close to, those of glycopyrrolate and N-methylscopolamine. They caused pupil dilation in rabbit eyes, but their mydriatic effects lasted for considerably less time than that of glycopyrrolate, and they did not induce dilation of the pupil in the contralateral, water-treated eyes, indicating that, in agreement with their soft nature, they are locally active, but safe and with a low potential to cause systemic side-effects.

Brain tissue sodium concentration in multiple sclerosis: a sodium imaging study at 3 tesla

Neuro-axonal degeneration occurs progressively from the onset of multiple sclerosis and is thought to be a significant cause of increasing clinical disability. Several histopathological studies of multiple sclerosis and experimental autoimmune encephalomyelitis have shown that the accumulation of sodium in axons can promote reverse action of the sodium/calcium exchanger that, in turn, leads to a lethal overload in intra-axonal calcium. We hypothesized that sodium magnetic resonance imaging would provide an indicator of cellular and metabolic integrity and ion homeostasis in patients with multiple sclerosis. Using a three-dimensional radial gradient-echo sequence with short echo time, we performed sodium magnetic resonance imaging at 3 T in 17 patients with relapsing-remitting multiple sclerosis and in 13 normal subjects. The absolute total tissue sodium concentration was measured in lesions and in several areas of normal-appearing white and grey matter in patients, and corresponding areas of white and grey matter in controls. A mixed model analysis of covariance was performed to compare regional tissue sodium concentration levels in patients and controls. Spearman correlations were used to determine the association of regional tissue sodium concentration levels in T(2)- and T(1)-weighted lesions with measures of normalized whole brain and grey and white matter volumes, and with expanded disability status scale scores. In patients, tissue sodium concentration levels were found to be elevated in acute and chronic lesions compared to areas of normal-appearing white matter (P < 0.0001). The tissue sodium concentration levels in areas of normal-appearing white matter were significantly higher than those in corresponding white matter regions in healthy controls (P < 0.0001). The tissue sodium concentration value averaged over lesions and over regions of normal-appearing white and grey matter was positively associated with T(2)-weighted (P < or = 0.001 for all) and T(1)-weighted (P < or = 0.006 for all) lesion volumes. In patients, only the tissue sodium concentration value averaged over regions of normal-appearing grey matter was negatively associated with the normalized grey matter volume (P = 0.0009). Finally, the expanded disability status scale score showed a mild, positive association with the mean tissue sodium concentration value in chronic lesions (P = 0.002), in regions of normal-appearing white matter (P = 0.004) and normal-appearing grey matter (P = 0.002). This study shows the feasibility of using in vivo sodium magnetic resonance imaging at 3 T in patients with multiple sclerosis. Our findings suggest that the abnormal values of the tissue sodium concentration in patients with relapsing-remitting multiple sclerosis might reflect changes in cellular composition of the lesions and/or changes in cellular and metabolic integrity. Sodium magnetic resonance imaging has the potential to provide insight into the pathophysiological mechanisms of tissue injury when correlation with histopathology becomes available.