Data on the effect of NbC inoculants on the elastic and microstructural evolution of LBP-DED IN718.

The use of inoculants added to precursor powder is a method of influencing grain growth during fabrication. Niobium carbide (NbC) particles have been added to IN718 gas atomised powder for additive manufacturing via laser-blown-powder directed-energy-deposition (LBP-DED). The collected data in this study reveals the effects of the NbC particles on the grain structure, texture and elastic properties, and oxidative properties of LBP-DED IN718 in the As-DED and heat-treated conditions. The microstructure was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with electron backscattered diffraction (EBSD), and transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy (EDS). Resonant ultrasound spectroscopy (RUS) was used to measure the elastic properties and phase transitions during standard heat treatments. Thermogravimetric analysis (TGA) is used to probe the oxidative properties at 650°C.

Data on the occurrence of a Brass texture and elastic anisotropy in laser blown powder processed superalloy IN718.

The additive manufacturing (AM) of components through laser-blown-powder directed-energy-deposition (LBP-DED) is highly applicable to the repair of aerospace components. Fabrication of superalloys with this technique, as with other AM methods, often encounters complications that include the formation of undesired phases, irregular microstructure and texture leading to anisotropic elastic properties. Heat treatments and other post-processing techniques can be used to mitigate these issues. The collected data demonstrates the effects of different heat treatment protocols on the microstructure, elastic properties, and hardness of LBP-DED IN718. In this study eight different heat treatment were used to investigate the effects of treatment time and temperature. The microstructure was investigated through SEM, with XRD and EDX used for phase analysis. The texture was characterised using SEM coupled with EBSD and the elastic properties were determined from resonant ultrasound spectroscopy.

Softening non-metallic crystals by inhomogeneous elasticity.

High temperature structural materials must be resistant to cracking and oxidation. However, most oxidation resistant materials are brittle and a significant reduction in their yield stress is required if they are to be resistant to cracking. It is shown, using density functional theory, that if a crystal's unit cell elastically deforms in an inhomogeneous manner, the yield stress is greatly reduced, consistent with observations in layered compounds, such as Ti3SiC2, Nb2Co7, W2B5, Ta2C and Ta4C3. The mechanism by which elastic inhomogeneity reduces the yield stress is explained and the effect demonstrated in a complex metallic alloy, even though the electronegativity differences within the unit cell are less than in the layered compounds. Substantial changes appear possible, suggesting this is a first step in developing a simple way of controlling plastic flow in non-metallic crystals, enabling materials with a greater oxidation resistance and hence a higher temperature capability to be used.

Phenotype of exogenous microparticle-containing pigment cells of the human Peyer's patch in inflamed and normal ileum.

OBJECTIVES: Pigmented cells, that contain inert, submicron-sized dietary particles, are a consistent feature of the base of human Peyer's patches (PP). We aimed (i) to phenotype these intestinal pigment cells (PC) in archival tissue specimens and (ii) to establish whether PC phenotype is altered in inflammatory conditions, especially Crohn's disease (CD). METHODS: PCs contained within PP were identified by routine haematoxylin and eosin (H&E) staining and dark field microscopy of archival ileal sections for: adenocarcinoma (n=16), colonic CD (n=23), non-CD colitis (n=10). Paraffin-embedded serial sections were graded for microscopic inflammation and then investigated immunohistochemically with antibodies against CD68, MAC387, CD14, CD11b, CD15, CD1a, S100, HLA-DR, CD86 and Cathepsin D. Analyses were by light and confocal microscopies. RESULTS: The majority of PCs were CD68 positive (circa 80%) with a minority (circa 20%) staining for MAC387. Microparticles were mainly identified within cathepsin D negative lysosomal compartments. Histological inflammatory grade and disease type had no influence on cell phenotype. CONCLUSIONS: The microparticle-containing PCs of the PP base are mainly mature macrophages (CD68) of low metabolic and immunological activity. There is no evidence of differential PC phenotype or activation in differing disease states, including CD.

Peripheral blood mononuclear cell proliferative responses to soluble and particulate heat shock protein 65 in health and inflammatory bowel disease.

OBJECTIVES: The aims of this study were to determine, in peripheral blood mononuclear cells (PBMC), whether particulate antigen triggers (i) an amplified cell proliferative response compared to soluble antigen and (ii) a dysfunctional response in cells derived from patients with chronic inflammation and specifically in those with inflammatory bowel disease (IBD). SUBJECTS: Healthy volunteers (n = 17), inflammatory controls (n = 8) and patients with IBD (n = 17) were recruited from St Thomas' and Guys' Hospital, London, UK. METHODS: Following optimisation of experimental conditions (0.1-10.0 mug/ml antigen), PBMC were stimulated with (i) 10.0 mug/ml recombinant soluble heat shock protein 65 (hsp 65) and (ii) 1.0 and 10.0 mug/ml hsp 65 conjugated to microparticles (0.5 mum diameter). PBMC proliferative responses were measured by (3)H-Thymidine incorporation at day 5 and results compared between groups using unpaired t-test. RESULTS: Conjugation to microparticles of low dose hsp 65 significantly increased overall proliferative responses by 2-11 fold compared to soluble antigen alone (p < 0.05). However, no specific PBMC proliferative dysregulation was noted in cells from subjects with IBD. CONCLUSIONS: Low dose antigen, in microparticulate form, leads to amplified cell proliferation in primary human cells, as showed previously in cell lines and animal studies. However there is no abnormal proliferative response in cells from subjects with IBD.

Immunolocalization of duodenal cytochrome B: a relationship with circulating markers of iron status.

BACKGROUND: The brush border ferric reductase (Dcytb) is critical for the absorption of dietary iron and appears to be expressed on the duodenal enterocyte brush border. The Dcytb expression is increased in severe iron-deficient anaemia, but the situation in a more typical mild iron deficiency is unclear. This study investigated Dcytb expression in patients with normal iron status or mild iron deficiency and its relationships with enterocyte iron status. MATERIALS AND METHODS: Duodenal biopsy specimens and blood samples were obtained from 32 patients undergoing routine upper gastrointestinal endoscopy. Twenty-three specimens (six iron-deficient and 17 iron-replete) were processed for light-microscopy (LM) and for immunohistochemistry with antibodies against Dcytb and heavy/light chain ferritin subunits. The nine remaining biopsies (three iron-deficient and six iron-replete) were processed for electron microscopy (EM). Immunolocalization of Dcytb and intracellular ferritin was performed with appropriate primary antibodies followed by 10-nm gold conjugate labels. RESULTS: The LM process showed a strong negative correlation between immunolabelling intensity of Dcytb on the enterocyte brush border and serum iron saturation (P < 0.001), but only a weak negative correlation between this antigen and haemoglobin (P = 0.08) or serum ferritin concentrations (P = 0.4). EM confirmed anti-Dcytb preferential labelling of microvilli rather than enterocyte cytoplasm (P = 0.001), but preferential antiferritin labelling of cytoplasm (P < 0.02). There was no correlation with enterocyte cytoplasmic ferritin labelling (i.e. enterocyte iron status and Dcytb expression). CONCLUSIONS: Enterocyte Dcytb brush border expression is increased even in mild iron deficiency and may be related to serum iron saturation. The lack of correlation with enterocyte ferritin expression deserves further study with direct measurement of intracellular iron.

A provisional database for the silicon content of foods in the United Kingdom.

Si may play an important role in bone formation and connective tissue metabolism. Although biological interest in this element has recently increased, limited literature exists on the Si content of foods. To further our knowledge and understanding of the relationship between dietary Si and human health, a reliable food composition database, relevant for the UK population, is required. A total of 207 foods and beverages, commonly consumed in the UK, were analysed for Si content. Composite samples were analysed using inductively coupled plasma-optical emission spectrometry following microwave-assisted digestion with nitric acid and H(2)O(2). The highest concentrations of Si were found in cereals and cereal products, especially less refined cereals and oat-based products. Fruit and vegetables were highly variable sources of Si with substantial amounts present in Kenyan beans, French beans, runner beans, spinach, dried fruit, bananas and red lentils, but undetectable amounts in tomatoes, oranges and onions. Of the beverages, beer, a macerated whole-grain cereal product, contained the greatest level of Si, whilst drinking water was a variable source with some mineral waters relatively high in Si. The present study provides a provisional database for the Si content of UK foods, which will allow the estimation of dietary intakes of Si in the UK population and investigation into the role of dietary Si in human health.

Functional interactions between mucosal IL-1, IL-ra and TGF-beta 1 in ulcerative colitis.

OBJECTIVE: Studies aiming to define key cytokines in inflammatory bowel disease have been restricted to gene expression or protein quantitation but lack functional information on cytokine interactions. Some of the major cytokines that govern the extent and duration of the inflammatory process in ulcerative colitis (UC), appear to be interleukin 1 (IL-1), its natural inhibitor IL-1 receptor antagonist (IL-1ra) and transforming growth factor beta1 (TGF-beta 1). Indeed, as a predictor of inflammation, the mucosal status of IL-1, depicted as a ratio of IL-1ra/IL-1, has often been used. METHODS: Using an IL-1 bioassay and specific anti-cytokine antibodies we have identified the functional role of these cytokines and their interactions in mucosal biopsy samples taken from patients with UC. RESULTS: Compared with control specimens, the secreted and tissue levels of IL-1 were consistently raised in UC samples. Levels of IL-1, rather than IL-1ra or the ratio of IL-1ra/IL-1, most closely mirrored the severity of inflammation. Using specific antibodies we showed that IL-1ra and TGF-beta 1 appear to modulate the degree of inflammation at different stages of the inflammatory process. Only in severely inflamed tissue, when IL-1 levels were high did IL-1ra inhibit IL-1-induced activity. In contrast, the levels of TGF-beta 1, and its effect in controlling inflammation, was most marked in mild but not severe UC. CONCLUSIONS: The functional roles of these cytokines in the inflammatory process can now be more carefully elucidated using a bioassay and specific neutralising antibodies.

Competition between IL-1, IL-1ra and TGF-beta 1 modulates the response of the ELA4.NOB-1/CTLL bioassay: implications for clinical investigations.

OBJECTIVE: The use of ELISA techniques to measure cytokine levels in clinical samples has chiefly replaced more labour intensive bioassays. ELISA measurements, however, do not reflect the functional activity of a cytokine within a sample; interleukin-1 (IL-1), for example, has two agonist isoforms (IL-1 alpha and IL-1 beta) and a competitive receptor antagonist (IL-1ra), and can be regulated by transforming growth factor beta1 (TGF-beta 1). The net effect of these cytokines, rather than IL-1 levels, are frequently suggested to regulate tissue inflammation, but confirming this has been difficult. METHODS: We used the ELA4.NOB-1/CTLL co-culture IL-1 bioassay to investigate whether IL-1 activity was inhibited by IL-1ra and TGF-beta 1 in a predictable manner. RESULTS: Thymidine incorporation into CTLL cells, induced by IL-1, was reduced dose dependently by IL-1ra and TGF-beta 1. With optimal levels of IL-1 CTLL responsiveness was reduced by 90% by 1 ng/ml TGF-beta 1 and completely abolished by 100 ng/ml IL-1ra. As expected, TGF-beta 1 and IL-1ra had independent mechanisms of action on the bioassay cell lines, and, in combination, they caused an additive, but not synergistic, effect. Importantly, the effect of these cytokines could be completely abolished in the presence of neutralising antibodies. CONCLUSIONS: Bioassay should provide specific functional information on the net IL-1 activity of clinical samples, while the use of specific antibodies could ascertain the contribution of individual cytokines within such samples.

Unconjugated bilirubin in human bile: the nucleating factor in cholesterol cholelithiasis?

AIMS: To investigate the concentrations of bilirubin, bilirubin conjugates, phospholipid, and cholesterol in the gall bladder bile obtained at surgery from patients with and without cholesterol gallstones. METHODS: Gall bladder bile was collected during surgery, by puncture, from 20 patients with gallstones undergoing routine cholecystectomy and from eight patients with normal liver blood tests. Concentrations of bilirubin, bilirubin conjugates, phospholipid, and cholesterol were measured using standard procedures. RESULTS: The proportion of total bilirubin that was unconjugated was significantly higher in the bile from patients with stones than in bile from control patients, whether or not the bile from either group was saturated with cholesterol or not. Indeed, the mean concentration of cholesterol was significantly higher in control bile samples. CONCLUSION: The presence of stones was more closely related to the proportion of unconjugated bilirubin than to the degree of saturation of bile with cholesterol. Bilirubin and its metabolites probably play an important part in the formation of cholesterol gallstones.

Orthosilicic acid stimulates collagen type 1 synthesis and osteoblastic differentiation in human osteoblast-like cells in vitro.

Silicon deficiency in animals leads to bone defects. This element may therefore play an important role in bone metabolism. Silicon is absorbed from the diet as orthosilicic acid and concentrations in plasma are 5-20 microM. The in vitro effects of orthosilicic acid (0-50 microM) on collagen type 1 synthesis was investigated using the human osteosarcoma cell line (MG-63), primary osteoblast-like cells derived from human bone marrow stromal cells, and an immortalized human early osteoblastic cell line (HCC1). Collagen type 1 mRNA expression and prolyl hydroxylase activity were also determined in the MG-63 cells. Alkaline phosphatase and osteocalcin (osteoblastic differentiation) were assessed both at the protein and the mRNA level in MG-63 cells treated with orthosilicic acid. Collagen type 1 synthesis increased in all treated cells at orthosilicic acid concentrations of 10 and 20 microM, although the effects were more marked in the clonal cell lines (MG-63, HCCl 1.75- and 1.8-fold, respectively, P < 0.001, compared to 1.45-fold in the primary cell lines). Treatment at 50 microM resulted in a smaller increase in collagen type 1 synthesis (MG-63 1.45-fold, P = 0.004). The effect of orthosilicic acid was abolished in the presence of prolyl hydroxylase inhibitors. No change in collagen type 1 mRNA level was seen in treated MG-63 cells. Alkaline phosphatase activity and osteocalcin were significantly increased (1.5, 1.2-fold at concentrations of 10 and 20 microM, respectively, P < 0.05). Gene expression of alkaline phosphatase and osteocalcin also increased significantly following treatment. In conclusion, orthosilicic acid at physiological concentrations stimulates collagen type 1 synthesis in human osteoblast-like cells and enhances osteoblastic differentiation.

Rapid non-equilibrium aluminium-ligand interactions: studies on the precipitation of aluminium by laser light scattering, ultrafiltration and centrifugation.

The study aimed to develop simple assays to study aluminium-ligand interactions in natural/biological systems where equilibrium is rarely reached and thus where the initial seconds or hours of interactions are important. The immediate and non-equilibrium precipitation of aluminium hydroxide, in aqueous solution at neutral pH, was therefore studied by laser light scattering (diffraction), ultrafiltration and centrifugation. The interaction of weak ligands, present in the gastrointestinal lumen, on the precipitation of aluminium hydroxide was also investigated. The initial kinetics and particle sizes of precipitated aluminium hydroxide were sensitive to a number of external factors, including the presence of weak ligand (bicarbonate), sheer force (stirring), electrolyte concentration and initial (i.e. added) aluminium concentration. However, after a few seconds (no weak ligand), or several hundred seconds (with weak ligand), the subsequent observed changes to the solid phase were of small magnitude and occurred slowly. Thus, a 25-min window, within 5 and 30 min of pH adjustment, can be used to study the interactions of aluminium-ligand. This may approximate better to most natural systems where unperturbed aluminium-ligand equilibrium must rarely exist.

Is eradication of Helicobacter pylori with colloidal bismuth subcitrate quadruple therapy safe?

BACKGROUND: When standard triple therapy fails to eradicate Helicobacter pylori, quadruple 'rescue' therapy is often used which, in Europe, generally comprises colloidal bismuth subcitrate (CBS) based triple therapy and a proton pump inhibitor. Since hypochlorhydria could greatly increase absorption of the toxic bismuth ion from CBS, we investigated the bismuth status of patients receiving anti-H. pylori quadruple therapy. MATERIALS AND METHODS: In a prospective open label study 34 patients with nonulcer dyspepsia or peptic ulcer disease, who had failed to eradicate H. pylori with standard triple therapy, were subsequently treated with CBS, omeprazole, amoxycillin and metronidazole (BOAM). A further 35 patients received triple therapy for the eradication of H. pylori: CBS, amoxycillin and metronidazole (BAM) (n = 18); placebo bismuth, amoxycillin and metronidazole (AM) (n = 9); or omeprazole, amoxycillin and metronidazole (OAM) (n = 8). Whole blood bismuth levels were determined before and within 24 hours of completing treatment. Analysis of bismuth was by inductively coupled plasma mass spectrometry, and concentrations were compared between groups and with the Hillemand 'alarm level' for blood bismuth (50-100 microg/l). RESULTS: BOAM gave higher blood bismuth levels than BAM (difference in means 13.1, CI 6.0-20.2, p <.001); three (8.8%) patients taking BOAM had concentrations within the Hillemand alarm level at 54.2, 64.7 and 91.8 microg/l. OAM and AM did not alter baseline blood bismuth levels. CONCLUSIONS: Caution should be observed in prescribing CBS with gastric acid suppression, and alternative bismuth preparations should be considered.

Efficacy and tolerability of a low microparticle diet in a double blind, randomized, pilot study in Crohn's disease.

BACKGROUND: Ultrafine and fine particles are potent adjuvants in antigen-mediated immune responses, and cause inflammation in susceptible individuals. Following recent findings that microparticles accumulate in the phagocytes of intestinal lymphoid aggregates, this study is the first investigation of whether their reduction in the diet improves the symptoms of Crohn's disease. METHODS: In a double blind study, 20 patients with active corticosteroid-treated ileal or ileo-colonic Crohn's disease randomly received either a low microparticle diet (trial group; n = 10) or a control diet (n = 10) for 4 months. Crohn's disease activity index (CDAI) and corticosteroid requirements were compared. RESULTS: One patient in each group was withdrawn. In the trial group there was a progressive decrease in CDAI from entry (392 +/- 25) to month 4 (145 +/- 47) (P = 0.002 vs control group) and seven patients were in remission (CDAI <150). In contrast, the control group had returned to baseline levels (302 +/- 28 on entry and 295 +/- 25 at month 4), with none in remission. Corticosteroid intake was reduced more in the trial group although this did not reach significance. CONCLUSIONS: A low microparticle diet may be effective in the management of ileal Crohn's disease and could explain the efficacy of elemental diets, which similarly are low in microparticles.

Embryonic epinephrine synthesis in the rat heart before innervation: association with pacemaking and conduction tissue development.

Epinephrine is a potent neurotransmitter and hormone that can influence cardiac performance beginning shortly after the first myocardial contractions occur in developing vertebrate embryos. In the present study, we provide evidence that the heart itself may produce epinephrine during embryonic development. Using antibodies that selectively recognize the catecholamine biosynthetic enzymes, tyrosine hydroxylase, dopamine ss-hydroxylase, and phenylethanolamine N-methyltransferase, we used coimmunofluorescent staining techniques to identify cardiac cells that have the capability of producing catecholamines. Initially, cells expressing catecholamine biosynthetic enzymes were found interspersed throughout the myocardium, but by embryonic day 11.5 (E11.5), they became preferentially localized to the dorsal venous valve and atrioventricular canal regions. As development proceeded, catecholamine biosynthetic enzyme expression decreased in these regions but became quite strong along the crest of the interventricular septum by E16.5. This expression pattern was also transient, decreasing in the ventricular septum by E19.5. These data are consistent with a transient and progressive association of catecholamine-producing cells within regions of the heart that become the sinoatrial node, atrioventricular node, and bundle of His. This is the first evidence demonstrating that intrinsic cardiac adrenergic cells may be preferentially associated with early pacemaking and conduction tissue development.

Conotruncal anomalies in the trisomy 16 mouse: an immunohistochemical analysis with emphasis on the involvement of the neural crest.

The trisomy 16 (Ts16) mouse is generally considered a model for human Down's syndrome (trisomy 21). However, many of the cardiac defects in the Ts16 mouse do not reflect the heart malformations seen in patients suffering from this chromosomal disorder. In this study we describe the conotruncal malformations in mice with trisomy 16. The development of the outflow tract was immunohistochemically studied in serially sectioned hearts from 34 normal and 26 Ts16 mouse embryos ranging from 8.5 to 14.5 embryonic days. Conotruncal malformations observed in the Ts 16 embryos included double outlet right ventricle, persistent truncus arteriosus, Tetralogy of Fallot, and right-sided aortic arch. This spectrum of malformations is remarkably similar to that seen in humans suffering from DiGeorge syndrome (DGS). As perturbation of neural crest development has been proposed in the pathogenesis of DGS we specifically focussed on the fate of neural crest derived cells during outflow tract development of the Ts16 mouse using an antibody that enabled us to trace these cells during development. Severe perturbation of the neural crest-derived cell population was observed in each trisomic specimen. The abnormalities pertained to: 1) the size of the columns of neural crest-derived cells (or prongs); 2) the spatial orientation of these prongs within the mesenchymal tissues of the outflow tract; and 3) the location in which the neural crest cells interact with the myocardium. The latter abnormality appeared to be responsible for ectopic myocardialization found in trisomic embryos. Our observations strongly suggest that abnormal neural crest cell behavior is involved in the pathogenesis of the conotruncal malformations in the Ts16 mouse.

Clearance of refractory bile duct stones with extracorporeal shockwave lithotripsy.

BACKGROUND: Extracorporeal shockwave lithotripsy (ESWL) has been used since the mid-1980s to fragment bile duct stones which cannot be removed endoscopically. Early machines required general anaesthesia and immersion in a waterbath. AIMS: To investigate the effectiveness of the third generation Storz Modulith SL20 lithotriptor in fragmenting bile duct stones that could not be cleared by mechanical lithotripsy. METHODS: Eighty three patients with retained bile duct stones were treated. All patients received intravenous benzodiazepine sedation and pethidine analgesia. Stones were targeted by fluoroscopy following injection of contrast via a nasobiliary drain or T tube. Residual fragments were cleared at endoscopic retrograde cholangiopancreatography. RESULTS: Complete stone clearance was achieved in 69 (83%) patients and in 18 of 24 patients (75%) who required more than one ESWL treatment. Stone clearance was achieved in all nine patients (100%) with intrahepatic stones and also in nine patients (100%) referred following surgical exploration of the bile duct. Complications included six cases of cholangitis and one perinephric haematoma which resolved spontaneously. CONCLUSION: Using the Storz Modulith, 83% of refractory bile duct calculi were cleared with a low rate of complications. These results confirm that ESWL is an excellent alternative to surgery in those patients in whom endoscopic techniques have failed.