Engineering a Bacillus subtilis expression-secretion system with a strain deficient in six extracellular proteases

We describe the development of an expression-secretion system in Bacillus subtilis to improve the quality and quantity of the secreted foreign proteins. This system consists of a strain (WB600) deficient in six extracellular proteases and a set of sacB-based expression vectors. With the inactivation of all six chromosomal genes encoding neutral protease A, subtilisin, extracellular protease, metalloprotease, bacillopeptidase F, and neutral protease B, WB600 showed only 0.32% of the wild-type extracellular protease activity. No residual protease activity could be detected when WB600 was cultured in the presence of 2 mM phenylmethylsulfonyl fluoride. By using TEM beta-lactamase as a model, we showed that WB600 can significantly improve the stability of the secreted enzyme. To further increase the production level we constructed an expression cassette carrying sacY, a sacB-specific regulatory gene. This gene was placed under the control of a strong, constitutively expressed promoter, P43. With this cassette in the expression vector, an 18-fold enhancement in beta-lactamase production was observed. An artificial operon, P43-sacY-degQ, was also constructed. However, only a partial additive enhancement effect (24-fold enhancement) was observed. Although degQ can stimulate the production of beta-lactamase in the system, its ability to increase the residual extracellular protease activity from WB600 limits its application. The use of the P43-sacY cassette and WB600 would be a better combination for producing intact foreign proteins in high yield.

Synthesis, Photoluminescence, and Adsorption of CdS/Dendrimer Nanocomposites

CdS/dendrimer nanocomposites can be synthesized from methanolic Cd(2+) and S(2-) with amine-terminated polyamidoamine dendrimers of generation 8 (G8NH(2)) as stabilizers. By controlling the preparation conditions, nanoparticles with diameters < or = 2 nm can be obtained with a narrow size distribution. They show blue photoluminescence at approximately 450 nm. We studied the effects of various additives on the photoluminescence and elucidated its mechanism. Stable aggregates of two to three G8NH(2) molecules with several CdS nanoparticles form; the particles are located at the surface of the G8NH(2) molecules. The adsorption of the CdS/G8NH(2) nanocomposites on flat substrate surfaces is determined by the substrate chemistry. The hydrophilic nature of G8NH(2) results in weak affinity to graphite but strong affinity to hydroxy-terminated substrates such as mica, oxidized silicon wafers, and carboxylate-terminated monolayers. Patterning of nanocomposites on these hydrophilic substrates is achieved by the microcontact printing method. We propose to use only one molecule, a large dendrimer, to control the nanoparticle formation and also the immobilization of the synthesized nanoparticle/dendrimer composites.

Wear performance of ultrahigh molecular weight polyethylene/quartz composites

Ultrahigh molecular weight polyethylene (UHMWPE)/quartz composites were compression molded in the presence of organosiloxane, and then hydrolyzed. The used organosiloxane is vinyl tri-ethyloxyl silane. The gelation, the melting behavior, the crystallinity, the mechanical properties and the wear resistance of UHMWPE/quartz composites were investigated. The results showed that organosiloxane can act as a cross-linking agent for UHMWPE matrix and serve as a coupling agent for improving the bonding between the quartz particles and the UHMWPE matrix. The correlation between the various properties and the morphology of the composites has been discussed. At about 0.5phr organsiloxane while the degree of crystallinity of the composite is at the peak value of 57%, the mechanical properties and the wear resistance of UHMWPE/quartz composites reaches their maximum.

Enhanced secretory production of a single-chain antibody fragment from Bacillus subtilis by coproduction of molecular chaperones

Formation of inclusion bodies is a major limiting factor for secretory production of an antidigoxin single-chain antibody (SCA) fragment from Bacillus subtilis. To address this problem, three new strains with enhanced production of molecular chaperones were constructed. WB600BHM constitutively produces the major intracellular molecular chaperones in an appropriate ratio without any heat shock treatment. This strain reduced the formation of insoluble SCA by 45% and increased the secretory production yield by 60%. The second strain, WB600B[pEPP], overproduces an extracytoplasmic molecular chaperone, PrsA. An increase in the total yield of SCA was observed. The third strain, WB600BHM[pEPP], coproduces both intracellular and extracytoplasmic molecular chaperones. This led to a further reduction in inclusion body formation and a 2.5-fold increase in the secretory production yield. SCA fragments secreted by this strain were biologically active and showed affinity to digoxin comparable to the affinity of those secreted by strains without overproduction of molecular chaperones. Interestingly, accumulation of a pool of periplasmic SCA was observed in the PrsA-overproducing strains. This pool is suggested to represent the secreted folding intermediates in the process of achieving their final configuration.

Cloning and expression of a novel protease gene encoding an extracellular neutral protease from Bacillus subtilis

We have cloned from Bacillus subtilis a novel protease gene (nprB) encoding a neutral protease by using a shotgun cloning approach. The gene product was determined to have a molecular mass of 60 kDa. It has a typical signal peptide-like sequence at the N-terminal region. The expression of nprB can be stimulated by using a B. subtilis strain, WB30, carrying a sacU(h)h mutation. Expression of this protease gene results in production of a 37-kDa protease in the culture medium. The first five amino acid residues from the N terminus of the mature protease were determined to be Ala-Ala-Gly-Thr-Gly. This indicates that the protease is synthesized in a preproenzyme form. The purified protease has a pH optimum of around 6.6, and its activity can be inhibited by EDTA, 1,10-phenanthroline (a zinc-specific chelator), and dithiothreitol. It retained 65% of its activity after treatment at 65 degrees C for 20 min. Sequence comparison indicates that the mature form of this protease has 66% homology with the two thermostable neutral proteases from B. thermoproteolyticus and B. stearothermophilus. It also shares 65, 61, and 56% homology with the thermolabile neutral proteases from B. cereus, B. amyloliquefaciens, and B. subtilis, respectively. The zinc-binding site and the catalytic residues are all conserved among these proteases. Sequence homology extends into the "propeptide" region. The nprB gene was mapped between metC and glyB and was not required for growth or sporulation.

Efficient production of a functional single-chain antidigoxin antibody via an engineered Bacillus subtilis expression-secretion system

We have applied a Bacillus subtilis expression-secretion system to produce a functional antidigoxin SCA (single-chain antibody consisting of VL-linker-VH) and the individual variable domains of light (VL) and heavy (VH) chains. The secreted antidigoxin SCA can be affinity purified in one step by applying the culture supernatant directly to a ouabain-Sepharose column. N-terminal sequence determination indicated that the protein has the expected N-terminus with the signal peptide properly processed. Affinity and ligand specificity studies demonstrated that the engineered antidigoxin SCA has almost identical properties as those of the parental monoclonal antibody. The use of B. subtilis WB600, an engineered, six-extracellular protease-deficient strain, is vital for the production of antidigoxin SCA in high quality and quantity (5 mg/liter in a shake flask culture). All the secreted SCAs are biologically active. The ability to produce secreted SCAs by the B. subtilis expression system provides a simple and efficient means to analyze the binding properties of engineered antibodies generated through rational design or site-directed mutagenesis.

Engineering of plasmin-resistant forms of streptokinase and their production in Bacillus subtilis: streptokinase with longer functional half-life

The short in vivo half-life of streptokinase limits its efficacy as an efficient blood clot-dissolving agent. During the clot-dissolving process, streptokinase is processed to smaller intermediates by plasmin. Two of the major processing sites are Lys59 and Lys386. We engineered two versions of streptokinase with either one of the lysine residues changed to glutamine and a third version with both mutations. These mutant streptokinase proteins (muteins) were produced by secretion with the protease-deficient Bacillus subtilis WB600 as the host. The purified muteins retained comparable kinetics parameters in plasminogen activation and showed different degrees of resistance to plasmin depending on the nature of the mutation. Muteins with double mutations had half-lives that were extended 21-fold when assayed in a 1:1 molar ratio with plasminogen in vitro and showed better plasminogen activation activity with time in the radial caseinolysis assay. This study indicates that plasmin-mediated processing leads to the inactivation of streptokinase and is not required to convert streptokinase to its active form. Plasmin-resistant forms of streptokinase can be engineered without affecting their activity, and blockage of the N-terminal cleavage site is essential to generate engineered streptokinase with a longer in vitro functional half-life.

Periodic ZnO nanorod arrays defined by polystyrene microsphere self-assembled monolayers

We demonstrate a low-cost and effective method to fabricate hexagonally patterned, vertically aligned ZnO nanorod arrays. Selective wet-etching is used to develop the catalyzing gold particle hexagonal pattern with the aid of a polystyrene microsphere self-assembled monolayer. The gold particles have tunable sizes independent of the polystyrene microsphere's diameter and are inherently round in shape. Each ZnO rod is grown individually from a catalyzing site via catalyst-initiated epitaxy, and the original hexagonal periodicity is well-preserved. The rods have flat ends, and the diameters of the rods can be controlled well by the amount of source materials. This method provides a promising way to create ZnO one-dimensional nanostructures for applications as two-dimensional photonic crystal, sensor arrays, nanolaser arrays, and optoelectronic devices.

Gene transfer and metabolic modulators as new therapies for pulmonary hypertension. Increasing expression and activity of potassium channels in rat and human models

Chronic Hypoxic Pulmonary Hypertension (CH-PHT) is characterized by pulmonary artery (PA) vasoconstriction and cell proliferation/hypertrophy. PA smooth muscle cell (PASMC) contractility and proliferation are controlled by cytosolic Ca++ levels, which are largely determined by membrane potential (E(M)). E(M) is depolarized in CH-PHT due to decreased expression and functional inhibition of several redox-regulated, 4-aminopyridine (4-AP) sensitive, voltage-gated K+ channels (Kv1.5 and Kv2.1). Humans with Pulmonary Arterial Hypertension (PAH) also have decreased PASMC expression of Kv1.5 and Kv2.1. We speculate this "K+-channelopathy" contributes to PASMC depolarization and Ca++ overload thus promoting vasoconstriction and PASMC proliferation. We hypothesized that restoration of Kv channel expression in PHT and might eventually be beneficial.

METHODS

Two strategies were used to increase Kv channel expression in PASMCs: oral administration of a metabolic modulator drug (Dichloroacetate, DCA) and direct Kv gene transfer using an adenovirus (Ad5-Kv2.1). DCA a pyruvate dehydrogenase kinase inhibitor, promotes a more oxidized redox state mimicking normoxia and previously has been noted to increase K+ current in myocytes. Rats were given DCA in the drinking water after the development of CH-PHT and hemodynamics were measured approximately 5 days later. We also tested the ability of Ad5-Kv2.1 to increase Kv2.1 channel expression and function in human PAs ex vivo.

RESULTS

The DCA-treated rats had decreased PVR, RVH and PA remodeling compared to the control CH-PHT rats (n=5/group, p<0.05). DCA restored Kv2.1 expression and PASMC Kv current density to near normoxic levels. Adenoviral gene transfer increased expression of Kv2.1 channels and enhanced 4-AP constriction in human PAs.

CONCLUSION

Increasing Kv channel function in PAs is feasible and might be beneficial.

Nitric oxide and renal nerve-mediated proximal tubular reabsorption in normotensive and hypertensive rats

In Inactin-anesthetized Wistar rats with an intact renal innervation, intratubular nitro-L-arginine methyl ester (L-NAME, 10(-4) M) increased proximal fluid uptake (J(va), at 2.47 +/- 0.61 x 10(-4) mm(3). mm(-2). s(-1)) by 17% (P < 0.05), whereas coadministration with sodium nitroprusside (SNP, 10(-4) M) decreased J(va) by 18% (P < 0.01). Similar manipulation of NO generation was without effect in groups of Wistar rats subjected to acute renal denervation. Intratubular aminoguanidine (10(-4) M), a selective inducible nitric oxide synthase (NOS) blocker, had no effect on J(va) in intact kidneys of Wistar rats, but the neuronal NOS (nNOS) blocker, 7-nitroindazole (10(-4) M and 10(-6) M) increased J(va) by 19-23% (both P < 0.001). In stroke-prone spontaneously hypertensive rats (SHRSP), J(va) values in the innervated kidneys were lower (P < 0.05) than in the corresponding Wistar groups and were unchanged by intratubular L-NAME or L-NAME plus SNP. The tonic attenuation of proximal epithelial transport by NO was dependent on the renal sympathetic nerves and appeared to be generated by the nNOS isoform of the enzyme. This role of NO was not evident in the SHRSP.

Incidence of lymphohaematopoietic malignancies in a petrochemical industry cohort: 1983-94 follow up

OBJECTIVES

In response to a previous finding of increased mortality from lymphohaematopoietic (LH) malignancies, this study examines incidence of LH malignancy in a petrochemical industry cohort. Emphasis is on chronic lymphocytic leukaemia (CLL) and on comparisons by period of first employment.

METHOD

The study cohort consists of 8942 employees who were active in the period 1970-92 and alive on 31 December 1982. Record linkage with the Louisiana tumour registry (LTR) provided information on cancer for cases occurring between 1983 and 1994. Standardised incidence ratios (SIR), with the south Louisiana population as a comparison, were computed for all cancers, all LH malignancies and specific LH subtypes. Analyses were conducted for sex and race categories, and by period of first employment, job type, duration of employment, and latency.

RESULTS

672 Cases of cancer were identified, including 59 LH malignancies. Women (n=1169) had an overall cancer SIR below unity and four LH malignancies versus 2.28 expected. Among the 7773 men, those first employed before 1950 had no overall cancer excess, a significant 1.4-fold increase in overall LH malignancies (43 observed versus 30.78 expected), and four CLL cases versus 3.27 expected. Findings for men first employed after 1950 are based on fewer cases, but there was no indication of excesses of overall cancer or LH malignancy. Numbers were too small in the group first employed after 1950 for meaningful analysis of LH malignancy subtypes such as CLL (one case).

CONCLUSION

These findings do not suggest a continuing excess of CLL but do suggest a small increase in incidence of overall LH malignancy for workers first employed before 1950. This may reflect associations with earlier workplace conditions, although work related patterns are mixed. Interpretation is limited by the diverse group of diseases within LH malignancies, and the lack of control for non-work factors other than sex, age, race, and period of diagnosis. This study has a major advantage of more complete and reliable cancer ascertainment compared with the mortality investigation, and shows the feasibility and benefits of using cancer registry incidence data in an occupational cohort study.

Prognostic Significance of Plasma CLEC-2 (C-Type Lectin-Like Receptor 2) in Patients With Acute Ischemic Stroke

Background and Purpose- CLEC-2 (C-type lectin-like receptor 2) is a C-type lectin receptor highly expressed on platelets with the prominent involvement in platelet activation, which was increased in coronary heart disease. Given the role of platelet activation in ischemic stroke and the connections between coronary heart disease and ischemic stroke, CLEC-2 might be a candidate marker of ischemic stroke. Here, we aimed to examine the prognostic significance of CLEC-2 in patients with acute ischemic stroke (AIS). Methods- Three hundred fifty-two patients with AIS within 7 days and 112 healthy controls were prospectively studied. Plasma CLEC-2 (pCLEC-2) and some conventional risk factors of stroke were examined. Stroke progression was defined as any new neurological symptoms/signs or any neurological worsening within 7 days after stroke onset, and poor prognosis was defined as modified Rankin Scale scores >2 at 90 days. The association between pCLEC-2 and stroke progression/prognosis was evaluated using regression models. Results- Patients with AIS had a significantly higher level of pCLEC-2 than that of healthy controls (P<0.05). Patients with AIS with progressive stroke or poor prognosis had a much higher level of pCLEC-2 compared with those with stable stroke or good prognosis (all P<0.05). Increasing pCLEC-2 was significantly associated with an increased risk of stroke progression (odds ratio, 1.97; 95% CI, 1.11-3.50; P=0.021) and poor prognosis (odds ratio, 1.70; 95% CI, 1.17-2.48; P=0.006). Patients with the highest pCLEC-2 level were 7- to 8-fold more likely to have stroke progression compared with the lowest quartile (odds ratio, 7.69; 95% CI, 1.43-41.41). Patients with the highest pCLEC-2 level were also more likely to have poor prognosis at 90 days (odds ratio, 5.58; 95% CI, 1.76-17.68). The optimal cutoff points of pCLEC-2 for predicting stroke progression and poor prognosis were 235.48 and 207.08 pg/mL, respectively. Conclusions- Increased pCLEC-2 was associated with stroke progression and poor prognosis at 90 days significantly, which indicates the prognostic role of pCLEC-2 in AIS. However, it needs to be confirmed in large-scale studies.

Expression of lipopolysaccharide binding protein and its receptor CD14 in experimental alcoholic liver disease

AIM: To evaluate the relationship between the expression of lipopolysaccharides (LPS) binding protein (LBP) and CD14 mRNA and the severity of liver injury in alcohol-fed rats.

METHODS: Twenty Wistar rats were divided into two groups: ethanol-fed group (group E) and control group (group C). Group E was fed with ethanol (5-12 g·kg¯¹·d¯¹) and group C received dextrose instead of ethanol. Rats of the two groups were sacrificed at 4 wk and 8 wk. Levels of endotoxin and alanine transaminase (ALT) in blood were measured, and liver pathology was observed under light and electronic microscopy. Expressions of LBP and CD14 mRNA in liver tissues were determined by RT-PCR analysis.

RESULTS: Plasma endotoxin levels were increased more significantly in group E (129 ± 21) ng·L¯¹ and (187 ± 35) ng·L¯¹ at 4 and 8 wk than in control rats (48 ± 9) ng·L¯¹ and (53 ± 11) ng·L¯¹, respectively (P < 0.05). Mean values of plasma ALT levels were (1867 ± 250) nkat·L¯¹ and (2450 ± 367) nkat·L¯¹ in Group E. The values were increased more dramatically in ethanol-fed rats than in Group C after 4 and 8 wk. In liver section from ethanol-fed rats, there were marked pathological changes (steatosis, cell infiltration and necrosis). In ethanol-fed rats, ethanol administration led to a significant increase in LBP and CD14 mRNA levels compared with the control group (P < 0.05).

CONCLUSION: Ethanol administration led to a significant increase in endotoxin levels in serum and LBP and CD14 mRNA expressions in liver tissues. The increase of LBP and CD14 mRNA expression might wake the liver more sensitive to endotoxin and liver injury.

Vascular effects of 17 beta-estradiol in male Sprague-Dawley rats

Bolus intravenous injections of 100 micrograms/kg 17 beta-estradiol significantly decreased the pressor responses to norepinephrine (NE; 0.3 microgram/kg) at the fourth, fifth, and sixth hour in anesthetized male Sprague-Dawley rats. At doses of 10(-6) to 3 x 10(-5) M, 17 beta-estradiol relaxed the sustained phase of contraction in male Sprague-Dawley rat tail artery helical strips precontracted in vitro by [Arg8]vasopressin (AVP), KCl, or NE. The effect was dose dependent. At doses of 3 x 10(-6) to 3 x 10(-5) M, it also decreased the initial phase of tension generation and extracellular Ca(2+)-dependent vasoconstriction induced by NE, AVP, or KCl in a dose-dependent manner in male Sprague-Dawley rat tail artery helical strips. 17 beta-Estradiol (2 x 10(-8) to 2 x 10(-6) M) decreased the voltage-dependent inward Ca2+ current and the intracellular free Ca2+ concentration ([Ca2+]i) increment induced by 15 mM KCl in a dose-dependent manner (3.6 x 10(-8) to 3.6 x 10(-6) M) in vascular smooth muscle cells (VSMC) isolated from male Sprague-Dawley rat tail arteries. We suggest that, at pharmacological doses, estrogen has a direct vasodilating effect on the rat tail artery that is mediated by its inhibitory effect on Ca2+ influx through voltage-dependent Ca2+ channels. The inhibitory effect of estrogen on the pressor responses to NE or AVP may be correlated with its modulation of VSMC [Ca2+]i through its actions on membrane Ca2+ channels.

Using Carbon Nanotubes to Absorb Low-Concentration Hydrogen Sulfide in Fluid

Hydrogen sulfide is a colorless and flammable gas under room temperature. Usually hydrogen sulfide is considered to be toxic; however, the recent research revealed that hydrogen sulfide in the cardiovascular system plays the role of a vascular dilator. The physiological role of hydrogen sulfide depends on its in vivo level. As such, the measurement of hydrogen sulfide with nano-quantity resolution becomes an important subject. Existing methods generally require bulky samples and are invasive and offline. It will be significantly helpful to measure hydrogen sulfide with a small amount of tissue in a noninvasive method The first attempt was to take a blood or serum sample with a trace amount to examine the interaction between hydrogen sulfide and carbon nanotube. The carbon nanotube is chosen because of a known fact that hydrogen sulfide can be adsorbed by activated carbon. The carbon nanotube is an excellent activated carbon in this regard. Fluorescence intensity of the carbon nanotube with and without immersion of it in a hydrogen sulfide medium was examined in the study. It was found that the intensities increase as the concentrations of hydrogen sulfide increase. Furthermore, the concentration of 10 microM hydrogen sulfide in water was successfully measured.

Interdependence of contractile responses of rat small mesenteric arteries on nitric oxide and cyclo-oxygenase and lipoxygenase products of arachidonic acid

1. We have examined the effects of nitric oxide inhibition, indomethacin and the dual lipoxygenase/cyclo-oxygenase inhibitor, 3-amino-1-[m-(trifluoromethyl)-phenyl]-2-pyrazoline (BW755C), on the responses of small mesenteric arteries of Wistar rats, with and without endothelium, to noradrenaline, potassium chloride, endothelin-1, acetylcholine and sodium nitroprusside. 2. Noradrenaline, potassium chloride and endothelin-1 caused concentration-dependent contraction of small mesenteric arteries. Indomethacin (14 microM) attenuated the contractile response to both noradrenaline and potassium chloride. The inhibitory action of indomethacin persisted in vessels treated with CHAPS. 3. Acetylcholine produced concentration-dependent relaxation in these vessels. Indomethacin (14 microM) had no significant effect on the acetylcholine concentration-response relationship. 4. NG-nitro-L-arginine methyl ester (L-NAME, 100 microM) potentiated the contractile response to both noradrenaline and potassium chloride and inhibited acetylcholine-induced relaxation. Indomethacin attenuated the effects of L-NAME. 5. BW755C inhibited the contractile response to noradrenaline and potassium chloride but not to endothelin-1. The inhibitory effects of BW755C persisted in the presence of indomethacin and in vessels treated with CHAPS. 6. BW755C enhanced endothelium-dependent relaxation, as assessed by the response to acetylcholine. In the presence of indomethacin, BW755C produced a shift to the right of the concentration-response curve to acetylcholine. 7. Inhibition of nitric oxide synthase with L-NAME, reversed the inhibitory effect of BW755C on noradrenaline- and potassium-induced contraction. L-NAME and BW755C in combination resulted in a shift to the right of the concentration-response curve to acetylcholine. 8. Sodium nitroprusside produced concentration-dependent relaxation of the vessels. Endothelium removal reduced the maximum relaxation to nitroprusside. BW755C did not alter the response to sodium nitroprusside in vessels with or without endothelium.9 .These data support the existence of two vasoconstrictor products of arachidonic acid released during contraction of small mesenteric arteries with noradrenaline and potassium chloride: a cyclo-oxygenase product and a lipoxygenase product both of which appear to be largely endothelium-independent.

Relative roles of nitric oxide and cyclo-oxygenase and lipoxygenase products of arachidonic acid in the contractile responses of rat renal arcuate arteries

1. We have examined the effects of inhibition of nitric oxide synthase, cyclo-oxygenase and lipoxygenase on the responses of renal arcuate arteries of Wistar rats, with and without endothelium, to noradrenaline, potassium chloride, endothelin-1, acetylcholine and sodium nitroprusside. 2. Noradrenaline, potassium chloride and endothelin-1 caused concentration-dependent contraction of the vessels. Indomethacin (14 microM) attenuated the contractile response to noradrenaline and to potassium chloride. The inhibitory effect of indomethacin persisted following endothelial removal. 3. Acetylcholine produced concentration-dependent relaxation of the vessels which was potentiated by indomethacin (14 microM). 4. NG-nitro-L-arginine methyl ester (L-NAME, 100 microM) did not affect the contractile response to either noradrenaline or potassium chloride but abolished relaxation to acetylcholine. In addition, L-NAME abolished the affects of indomethacin on acetylcholine-induced relaxation and noradrenaline- and potassium chloride-induced contraction. 5. BWC755C attenuated noradrenaline and potassium chloride-induced contraction. This effect persisted in the presence of indomethacin. 6. In vessels pretreated with CHAPS, BW755C inhibited both noradrenaline and potassium chloride-induced contraction. In these vessels BW755C had no additional inhibitory effect to indomethacin on noradrenaline- and potassium-induced contraction. 7. Inhibition of nitric oxide synthase with L-NAME (100 microM) attenuated the effect of BW755C on noradrenaline- and potassium-induced contraction. 8. BW755C alone did not affect endothelium-dependent relaxation as assessed by the response to acetylcholine. However, in the presence of indomethacin, BW755C inhibited acetylcholine-induced relaxation. 9. BW755C did not affect endothelium-independent relaxation as assessed by the response to sodium nitroprusside in vessels with or without endothelium. 10. These data support the existence of two vasoconstrictor products of arachidonic acid released during contraction of renal arcuate arteries with noradrenaline and potassium chloride. A cyclooxygenase product which appears to be endothelium-independent and the other an endothelium dependent lipoxygenase product.

Enhanced wear performance of ultra high molecular weight polyethylene crosslinked by organosilane

Ultra high molecular weight polyethylene (UHMWPE) crosslinked by organosilane was thermal compression molded. The organosilane used was the tri-ethyloxyl vinyl silane. Its gelation, melting behavior, crystallinity, mechanical and wear-resisting properties were systematically investigated. The results showed that the gel ratio of UHMWPE increases with the incorporation of organosilane. At a low content of organosilane, the melting point and crystallinity of the crosslinked UHMWPE increase, and hence the mechanical and wear-resisting properties are improved. However, at a high content of organosilane, these performances of the crosslinked UHMWPE become worse. At 0.4 phr silane, the wear resistance of crosslinked UHMWPE reaches its optimum value.

Global survival trends for brain tumors, by histology: analysis of individual records for 556,237 adults diagnosed in 59 countries during 2000-2014 (CONCORD-3)

BACKGROUND

Survival is a key metric of the effectiveness of a health system in managing cancer. We set out to provide a comprehensive examination of worldwide variation and trends in survival from brain tumors in adults, by histology.

METHODS

We analyzed individual data for adults (15-99 years) diagnosed with a brain tumor (ICD-O-3 topography code C71) during 2000-2014, regardless of tumor behavior. Data underwent a 3-phase quality control as part of CONCORD-3. We estimated net survival for 11 histology groups, using the unbiased nonparametric Pohar Perme estimator.

RESULTS

The study included 556,237 adults. In 2010-2014, the global range in age-standardized 5-year net survival for the most common sub-types was broad: in the range 20%-38% for diffuse and anaplastic astrocytoma, from 4% to 17% for glioblastoma, and between 32% and 69% for oligodendroglioma. For patients with glioblastoma, the largest gains in survival occurred between 2000-2004 and 2005-2009. These improvements were more noticeable among adults diagnosed aged 40-70 years than among younger adults.

CONCLUSIONS

To the best of our knowledge, this study provides the largest account to date of global trends in population-based survival for brain tumors by histology in adults. We have highlighted remarkable gains in 5-year survival from glioblastoma since 2005, providing large-scale empirical evidence on the uptake of chemoradiation at population level. Worldwide, survival improvements have been extensive, but some countries still lag behind. Our findings may help clinicians involved in national and international tumor pathway boards to promote initiatives aimed at more extensive implementation of clinical guidelines.

Microvascular corrosion casting of normal tissue, transitional mucosa and adenocarcinoma in the human colon

The microcirculatory architecture of normal tissue, transitional mucosa and adenocarcinoma of the human colon was investigated with microvascular corrosion casting (MVCC) combined with scanning electron microscopy (SEM). The study showed that the capillaries within the normal mucosa were arranged in a regular hexagonal pattern around the mucosal glands and that the microvessels of transitional mucosa mostly had lost the typical hexagonal pattern and become slightly wider in diameter. The microvessels in the tumor periphery were increased in number and disorganized, and presented large variation in morphology with claw-like formations, widened sinuses, diverticula and appendixoid patterns. Microvessels were lacking in the central areas of tumors. These morphological alterations may serve as additional indicators of tumor development.

Intensity-Stabilized Fast-Scanned Direct Absorption Spectroscopy Instrumentation Based on a Distributed Feedback Laser with Detection Sensitivity down to 4 × 10-6

A novel, intensity-stabilized, fast-scanned, direct absorption spectroscopy (IS-FS-DAS) instrumentation, based on a distributed feedback (DFB) diode laser, is developed. A fiber-coupled polarization rotator and a fiber-coupled polarizer are used to stabilize the intensity of the laser, which significantly reduces its relative intensity noise (RIN). The influence of white noise is reduced by fast scanning over the spectral feature (at 1 kHz), followed by averaging. By combining these two noise-reducing techniques, it is demonstrated that direct absorption spectroscopy (DAS) can be swiftly performed down to a limit of detection (LOD) (1σ) of 4 × 10-6, which opens up a number of new applications.

Cancer survivor perspectives on sharing patient-generated health data with central cancer registries

PURPOSE

Central cancer registries collect data and provide population-level statistics that can be tracked over time; yet registries may not capture the full range of clinically relevant outcomes. Patient-generated health data (PGHD) include health/treatment history, biometrics, and patient-reported outcomes (PROs). Collection of PGHD would broaden registry outcomes to better inform research, policy, and care. However, this is dependent on the willingness of patients to share such data. This study examines cancer survivors' perspectives about sharing PGHD with central cancer registries.

METHODS

Three U.S. central registries sampled colorectal, non-Hodgkin lymphoma, and metastatic breast cancer survivors 1-4 years after diagnosis, recruiting them via mail to participate in one of seven focus groups (n = 52). Group discussions were recorded, transcribed, and thematically analyzed.

RESULTS

Most survivor-participants were unaware of the existence of registries. After having registries explained, all participants expressed their willingness to share PGHD with them if treated confidentially. Participants were willing to provide information on a variety of topics (e.g., medical history, medications, symptoms, financial difficulties, quality of life, biometrics, nutrition, exercise, and mental health), with a focus on long-term effects of cancer and its treatment. Participants' preferred mode for providing data varied. Participants were also interested in receiving information from registries.

CONCLUSIONS

Our results suggest that registry-based collection of PGHD is acceptable to most cancer survivors and could facilitate registry-based efforts to collect PGHD/PROs. Central cancer registry-based collection of PGHD/PROs, especially on long-term effects, could enhance registry support of cancer control efforts including research and population health management.

Centimeter-long Ta3N5 nanobelts: synthesis, electrical transport, and photoconductive properties

Centimeter-long Ta3N5 nanobelts were synthesized by a reaction of centimeter-long TaS3 nanobelt templates with flowing NH3 at 800 °C for 2 h. The nanobelts have cross-sections of about 50 × 100 nm(2), and lengths up to 0.5 cm. A field effect transistor (FET) made of a single Ta3N5 nanobelt was fabricated on silica/silicon substrate. The electric transport of the individual nanobelt revealed that the nanobelt is a semiconductor with a room-temperature resistivity of 11.88 Ω m, and can be fitted well with an empirical formula ρ = 10831 exp(-T/43.8) - 22.6, where ρ is resistivity (Ω m) and T is absolute temperature (K). The FET showed decent photoconductive performance under light irradiation in the range 250-630 nm. The photocurrent increased by nearly 10 times the dark current under 450 nm light irradiation at an applied voltage of 5.0 V.

A Role of the Podoplanin-CLEC-2 Axis in Promoting Inflammatory Response After Ischemic Stroke in Mice

C-type lectin-like receptor 2 (CLEC-2) is a platelet surface-activating receptor with the prominent involvement in platelet activation, which was found to be associated with the progression and prognosis of acute ischemic stroke patients. Although podoplanin is the only known endogenous ligand for CLEC-2, the role of podoplanin/CLEC-2 in cerebral ischemia injury was unclear. In this study, we examined their role by using a mouse middle cerebral artery occlusion (MCAO) model. The expression of CLEC-2 and podoplanin increased after ischemia/reperfusion (I/R) injury, peaked at 24 h, and then decreased gradually. Podoplanin and CLEC-2 co-localized mainly in the ischemia/reperfusion cortex and expressed on neurons and microglia. Anti-podoplanin antibody pretreatment reduced cerebral infarct volume from 52.67 ± 4.67 to 34.08 ± 6.04% (P < 0.05) and attenuated the neurological deficits during acute stage and recovery stage. Moreover, a significant decrease of IL-18 and IL-1β was observed in the mice pretreated with the anti-podoplanin antibody. Our results demonstrate that the podoplanin-CLEC-2 axis might play an important role in cerebral ischemia/reperfusion injury in mice by promoting inflammatory reactions.

[The multicenter study on the registration and follow-up of low anticoagulation therapy for the heart valve operation in China]

OBJECTIVE

To investigate the optimal anticoagulation methods and monitoring strategy for Chinese patients undergoing heart valve replacement, which is potentially quite different from western populations.

METHODS

In this multicenter prospective cohort study, the anticoagulation and monitoring strategy data was acquired from 25 773 in-hospital patients in 35 medical centers and 20 519 patients in outpatient clinic in 11 medical centers from January 1st, 2011 to December 31th, 2015.

RESULTS

As for in-hospital patients, mean age of study population was (48.6±11.2) years old; main etiology of valve pathology was rheumatic (87.5%) origin among study cohort; 94.8% of study population received mechanical valve implantation; international normalized ratio (INR) monitoring (in all the study centers) and low-intensity anticoagulation strategy (31 hospitals chose target INR range of 1.5-2.5, and actual values of INR among 89.2% of 100 069 in-hospital monitoring samples were 1.5-2.5), with mean actual INR values of 1.84±0.53, and warfarin dosage of (2.82±0.93) mg/d were widely adopted among the study centers; strategies of in-hospital warfarin administration were similar in all the study centers; complication rates of low-intensity anticoagulation strategy were low in severe hemorrhage (0.02%), thrombosis (0.05%), and thromboembolism (0.05%) events, without anticoagulation-related death.As for 18 974 outpatient clinic patients, the follow-up rate was 92.47%, with a total of 30 012 patient-years (Pty). Anticoagulation-related morbidity and mortality rates were 0.67% and 0.15% Pty; major hemorrhage morbidity and mortality rates were 0.25% and 0.13% Pty; thromboembolism morbidity and mortality rates were 0.45% and 0.03% Pty.The mean dosage of warfarin daily dosage was (2.85±1.23) mg/d and INR value was 1.82±0.57.No significant regional difference in the intensity of anticoagulation therapy was noted during the study.

CONCLUSIONS

INR can be used as a normalized indicator for intensity of anticoagulation therapy in China.The optimal anticoagulation intensity with INR range from 1.5 to 2.5 is safe and effective for Chinese patients with heart valve replacement, and there is no significant regional difference in the intensity of anticoagulation therapy.