Liisa Virkki

Systematic review and meta-analysis of the efficacy and safety of existing TNF blocking agents in treatment of rheumatoid arthritis

Background and Objectives Five-tumour necrosis factor (TNF)-blockers (infliximab, etanercept, adalimumab, certolizumab pegol and golimumab) are available for treatment of rheumatoid arthritis. Only few clinical trials compare one TNF-blocker to another. Hence, a systematic review is required to indirectly compare the substances. The aim of our study is to estimate the efficacy and the safety of TNF-blockers in the treatment of rheumatoid arthritis (RA) and indirectly compare all five currently available blockers by combining the results from included randomized clinical trials (RCT). Methods A systematic literature review was conducted using databases including: MEDLINE, SCOPUS (including EMBASE), Cochrane library and electronic search alerts. Only articles reporting double-blind RCTs of TNF-blockers vs. placebo, with or without concomitant methotrexate (MTX), in treatment of RA were selected. Data collected were information of patients, interventions, controls, outcomes, study methods and eventual sources of bias. Results Forty-one articles reporting on 26 RCTs were included in the systematic review and meta-analysis. Five RCTs studied infliximab, seven etanercept, eight adalimumab, three golimumab and three certolizumab. TNF-blockers were more efficacious than placebo at all time points but were comparable to MTX. TNF-blocker and MTX combination was superior to either MTX or TNF-blocker alone. Increasing doses did not improve the efficacy. TNF-blockers were relatively safe compared to either MTX or placebo. Conclusions No single substance clearly rose above others in efficacy, but the results of the safety analyses suggest that etanercept might be the safest alternative. Interestingly, MTX performs nearly identically considering both efficacy and safety aspects with a margin of costs.

In situ production and analysis of Weissella confusa dextran in wheat sourdough

Several lactic acid bacteria belonging to the genera Leuconostoc, Lactobacillus, and Weissella have been introduced to wheat sourdough baking for in situ production of exopolysaccharides. This is considered a novel method for improving the shelf-life, volume and nutritional value of bread without additives. However, in situ production of exopolysaccharides during sourdough fermentation is challenged by simultaneous acidification due to metabolic activities of the bacteria, which may significantly diminish the positive technological impact of exopolysaccharides. In this study, the growth, activity and in situ production of dextran by Weissella confusa VTT E-90392 in wheat sourdoughs were investigated. Furthermore, the influence of dextran-enriched sourdoughs, at the addition level of 43%, on the subsequent bread quality was established. W. confusa efficiently produced dextran from the added sucrose in wheat sourdough without strong acid production. A new specific enzyme-assisted method for in situ analysis of dextran in sourdoughs was developed. With this method, we could for the first time proof significant (11-16 g/kg DW) production of polymeric dextran in sourdoughs. Concomitant formation of shorter isomaltooligosaccharides by W. confusa was also detected. The produced dextran significantly increased the viscosity of the sourdoughs. Application of dextran-enriched sourdoughs in bread baking provided mildly acidic wheat bread with improved volume (up to 10%) and crumb softness (25-40%) during 6 days of storage. Hence, W. confusa is a promising new strain for efficient in situ production of dextrans and isomaltooligosaccharides in sourdoughs without strong acidification.

NMR spectroscopic analysis of exopolysaccharides produced by Leuconostoc citreum and Weissella confusa.

Dextrans are the main exopolysaccharides produced by Leuconostoc species. Other dextran-producing lactic acid bacteria include Streptococci, Lactobacilli, and Weissella species. Commercial production and structural analysis has focused mainly on dextrans from Leuconostoc species, particularly on Leuconostoc mesenteroides strains. In this study, we used NMR spectroscopy techniques to analyze the structures of dextrans produced by Leuconostoc citreum E497 and Weissella confusa E392. The dextrans were compared to that of L. mesenteroides B512F produced under the same conditions. Generally, W. confusa E392 showed better growth and produced more EPS than did L. citreum E497 and L. mesenteroides B512F. Both L. citreum E497 and W. confusa E392 produced a class 1 dextran. Dextran from L. citreum E497 contained about 11% alpha-(1-->2) and about 3.5% alpha-(1-->3)-linked branches whereas dextran from W. confusa E392 was linear with only a few (2.7%) alpha-(1-->3)-linked branches. Dextran from W. confusa E392 was found to be more linear than that of L. mesenteroides B512F, which, according to the present study, contained about 4.1% alpha-(1-->3)-linked branches. Functionality, whether physiological or technological, depends on the structure of the polysaccharide. Dextran from L. citreum E497 may be useful as a source of prebiotic gluco-oligosaccharides with alpha-(1-->2)-linked branches, whereas W. confusa E392 could be a suitable alternative to widely used L. mesenteroides B512F in the production of linear dextran.

Structural characterization of water soluble β-glucan of oat bran

β-glucan was isolated from oat bran in a highly purified form. The bran was characterized for its contents of dietary fiber, β-glucan, fat and protein. The isolated β-glucan was free of protein and contained only glucose in GC sugar analysis. Two types of β-glucan were obtained with different solubilities. Their molar masses were 1.6 million for the less soluble and 1.1 million for the more readily soluble type. No structural differences were found. The two-dimensional correlation NMR spectrum of the isolated β-glucan showed that the glucose units are joined with 1,3- and 1,4-linkages only. The oligosaccharides produced by the action of a specific enzyme, lichenase, were analyzed by HPLC and capillary zone electrophoresis. The major products are 32-β-d-glucosyl cellobiose (trisaccharide) and 33-β-d-glucosyl cellotriose (tetrasaccharide), which account for 95% of the whole. Also, 34-β-d-glucosyl cellotetraose (pentasaccharide) and other oligosaccharides with degree of polymerization (DP) higher than 5 were detected as minor components.

The effect of phytic acid and some natural chelating agents on the solubility of mineral elements in oat bran

The effect of phytic acid on the solubility of mineral elements in oat bran was studied by digesting phytic acid with phytase enzyme. The combined effect of phytase treatment and the addition of three chelating agents common in food were also tested. Starch and proteins were digested enzymatically. The sample was dialysed, using an equilibrium dialysis method, and the soluble mineral elements were analysed from the dialyzate. The minerals studied were calcium, magnesium, iron, manganese, zinc, potassium and phosphorus. The chelating agents used were citric and malic acids and glucose. The phytase treatment increased the solubility of minerals less than expected. Citric acid was the most efficient chelating agent. The effect of malic acid was small. The results confirmed that the minerals were tightly bound to the dietary fibre of oat bran and were only partially released when the influence of phytic acid was reduced by degradation.

Comprehensive multidetector HPSEC study on solution properties of cereal arabinoxylans in aqueous and DMSO solutions.

The water-soluble arabinoxylans from wheat flour (high, medium, and low viscosity samples) and rye flour (high viscosity sample) were characterized by (1)H NMR spectroscopy and HPSEC with refractive index, light scattering, and viscometric detectors. These cereal arabinoxylans have recently been used as model arabinoxylans in various studies, but their solution properties have not been previously investigated. In this study, two HPSEC eluent systems were used: the water-based system and DMSO-based system. DMSO seemed to be a better solvent than water, especially for arabinoxylans containing a low amount of arabinose substituents. (1)H NMR spectroscopy indicated the structural differences between the analyzed arabinoxylan samples that also affected the hydrodynamic parameters obtained with HPSEC. Influence of arabinose side groups on the solution conformation of arabinoxylans could not be excluded based on our data, despite the role of arabinose substituents being questioned in previous investigations concerning arabinoxylan conformation in solution.

Androgen Deficiency and Defective Intracrine Processing of Dehydroepiandrosterone in Salivary Glands in Sjögren’s Syndrome

Objective We hypothesized that in addition to dehydroepiandrosterone (DHEA) depletion, Sjögren’s syndrome (SS) is characterized by local androgen deficiency in salivary glands and defects in local processing of DHEA. Methods Sex steroid levels in serum and saliva were measured using enzyme immunoassays. Androgen effects on salivary gland cells were analyzed using the cysteine-rich secretory protein-3 (CRISP-3) androgen biomarker. Results Serum and salivary concentrations of androgens were low in SS. Substrate to end-product ratios and correlations suggest that in SS salivary glands DHEA is effectively converted to testosterone, but that there are defects in converting testosterone further to dihydrotestosterone (DHT). In healthy controls no such phenomenon was seen, but testosterone is effectively converted to DHT. Salivary glands contained type I 5-α-reductase, and its inhibition with dutasteride completely blocked the upregulating effect of DHEA, but not of DHT, on CRISP-3 in human salivary gland acinar cells. Conclusion DHEA and DHT upregulate CRISP-3, which is reportedly low in SS. The effect of DHEA on CRISP-3 is indirect and is inhibited by dutasteride, showing that there is intracrine processing of DHEA in salivary glands. In healthy glands, but not in SS, DHEA is effectively taken up and converted to DHT. Sex steroid concentrations in saliva in part reflect glandular uptake of DHEAsulfate and local intracrine DHEA metabolism, which seem to be defective in SS. Our study demonstrates a prominent androgen deficiency and a defect in intracrine production of active androgens in SS salivary glands, also suggesting that salivary DHT cannot be maintained at a normal level in this female-dominant autoimmune exocrinopathy.

Step-wise enzymatic preparation and structural characterization of singly and doubly substituted arabinoxylo-oligosaccharides with non-reducing end terminal branches.

Shearzyme (GH10 endo-1,4-beta-D-xylanase) and two different alpha-L-arabinofuranosidases (AXH-m and AXH-d3) were used stepwise to manufacture arabinoxylo-oligosaccharides (AXOS) with alpha-L-Araf (1-->2)-monosubstituted beta-D-Xylp residues or alpha-L-Araf (1-->2)- and (1-->3) doubly substituted beta-D-Xylp residues from wheat arabinoxylan (AX) in a rather straightforward way. Four major AXOS (d-I, d-II, m-I and m-II) were formed in two separate hydrolyses. The AXOS were purified and the structures were confirmed using TLC, HPAEC-PAD, MALDI-TOF-MS and 1D and 2D NMR spectroscopy. The samples were identified as d-I: alpha-L-Araf-(1-->2)-[alpha-L-Araf-(1-->3)]-beta-D-Xylp-(1-->4)-beta-D-Xylp-(1-->4)-D-Xylp, d-II: alpha-L-Araf-(1-->2)-[alpha-L-Araf-(1-->3)]-beta-D-Xylp-(1-->4)-D-Xylp, m-I: alpha-L-Araf-(1-->2)-beta-D-Xylp-(1-->4)-beta-D-Xylp-(1-->4)-D-Xylp and m-II: alpha-L-Araf-(1-->2)-beta-D-Xylp-(1-->4)-D-Xylp. To our knowledge, this is the first report on structural (1)H and (13)C NMR analysis of xylobiose-derived AXOS d-II and m-II. The latter compound has not been reported previously. The doubly substituted AXOS were produced for the first time in good yields, as d-I and d-II corresponded to 11.8 and 5.6 wt% of AX, respectively. Singly alpha-L-Araf (1-->2)-substituted AXOS could also be prepared in similar yields by treating the doubly substituted AXOS further with AXH-d3.

Presence of 1->3-linked 2-O-β-D-xylopyranosyl-α-L-arabinofuranosyl side chains in cereal arabinoxylans.

The presence of a fairly uncommon side chain 2-O-beta-D-xylopyranosyl-alpha-L-arabinofuranosyl in arabinoxylans (AX) from eight different cereal by-products was investigated, using (1)H NMR spectroscopy and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) after Shearzyme (GH10 endo-1,4-beta-D-xylanase) hydrolysis. This disaccharide side group was present in significant amounts in AX extracted from corn cobs and barley husks. For the first time, it was also detected in AX from oat spelts and rice husks, and in lesser amounts in wheat straw AX. Arabinoxylo-oligosaccharide (AXOS) containing the 2-O-beta-D-Xylp-alpha-L-Araf side chain was purified from the oat spelt AX hydrolysate and the structure was fully analyzed using 1D and 2D NMR spectroscopy. The AXOS was identified as beta-D-Xylp-(1-->2)-alpha-L-Araf-(1-->3)-beta-D-Xylp-(1-->4)-D-Xyl. To our knowledge, such a structure with 2-O-beta-D-Xylp-alpha-L-Araf attached to the O-3 of the nonreducing end of xylobiose has not been described previously. New information on substitution of AX from various cereal by-products was obtained by combining NMR and enzyme-assisted HPAEC-PAD analysis.

Effects of Natural Chelating Agents on the Solubility of Some Physiologically Important Mineral Elements in Oat Bran and Oat Flakes

ABSTRACT The solubility of mineral elements from oat bran and flake samples was studied by a method using equilibrium dialysis after enzymatic digestion of starch and proteins. The effects of six potential chelating agents common in food were tested on the solubility of mineral elements. The minerals studied were calcium, magnesium, iron, manganese, zinc and potassium, and the chelating agents were citric, lactic, malic, and ascorbic acids, glucose and xylitol. The mineral elements were tightly bound to the dietary fiber of the samples. Bran fiber bound even the zinc and calcium contributed through the enzymes used. Adding citric, malic, or lactic acids increased the solubility of the mineral elements studied, except for potassium which was easily dialyzable as such. Iron was insoluble in all situations. Citric acid was the most efficient chelating agent in solubilizing the mineral elements. The effect of malic and lactic acids on the solubility of minerals was small. No effect was found with glucose, asc...