Human exposure assessment of fluoride from tea (Camellia sinensis L.): A UK based issue?

Fluoride concentrations in UK tea, including the leading supermarket economy labelled products, were determined. Fluoride ranged from 93 to 820 mg/kg in the products and 0.43 to 8.85 mg/L in the infusions. The UK supermarket economy teas contained elevated fluoride, ranging from 3.60 to 7.96 mg/L in a 2 minute brewing infusion, comparable to Chinese brick tea, indicating the use of mature leaves in their manufacture. Considering the dietary reference intake (DRI) of 4 mg/day of fluoride for an adult consuming 1 L of tea, prepared from an economy tea, containing 6.0 mg/L fluoride, 75–120% of the DRI fluoride is available for absorption by the human system in the presence of food, increasing to 150% when fasting. Excess fluoride in the diet can lead to detrimental health effects such as fluorosis of the teeth and skeletal fluorosis and consuming economy branded tea will lead to exposure.     

Tea and herbal infusions: Their antioxidant activity and phenolic profile

Tea and herbal infusions have been studied for their polyphenolic content, antioxidant activity and phenolic profile. The total phenolics recovered by ethyl acetate from the water extract, were determined by the Folin–Ciocalteu procedure and ranged from 88.1 ± 0.42 (Greek mountain tea) to 1216 ± 32.0 mg (Chinese green tea) GAE (Gallic acid equivalents)/cup. The antioxidant activity was evaluated by two methods, DPPH and chemiluminescence assays, using Trolox and quercetin as standards. The EC₅₀ of herbal extracts ranged from 0.151 ± 0.002 mg extract/mg DPPH (0.38 quercetin equivalents and 0.57 Trolox equivalents), for Chinese green tea, to 0.77 ± 0.012 mg extract/mg DPPH (0.08 quercetin equivalents and 0.13 Trolox equivalents), for Greek mountain tea. Chemiluminescence assay results showed that the IC₅₀ ranged from 0.17 ± 3.4 × 10⁻³ μg extract/ml of the final solution in the measuring cell (1.89 quercetin and 5.89 Trolox equivalents) for Chinese green tea, to 1.10 ± 1.86 × 10⁻² g extract/ml of the final solution in the measuring cell (0.29 quercetin and 0.90 Trolox equivalents) for Greek mountain tea. The phenolic profile in the herbal infusions was investigated by LC-DAD-MS in the positive electrospray ionization (ESI⁺) mode. About 60 different flavonoids, phenolic acids and their derivatives have been identified.     

White and green tea polyphenols inhibit pancreatic lipase in vitro

Green, white and black teas were assayed for inhibition of pancreatic lipase activity in vitro. White tea proved to be more effective than green tea with black tea showing little inhibition even at 200 μg GAE/ml. The EC₅₀ values for inhibition were 22 μg/ml for white tea and 35 μg/ml for green tea; both easily achievable from normal infusions of tea. Liquid chromatography-mass spectroscopy analysis showed that white and green teas had essentially equal amounts of flavan-3-ols but green tea had higher levels of flavonols. White tea had higher levels of 5-galloyl quinic acid, digalloyl glucose, trigalloyl glucose and the tannin, strictinin.After chromatography on Sephadex LH-20, the main inhibitory fraction was enriched in strictinin and fractions enriched in other components were ineffective. This suggests that strictinin content may be crucial for inhibition of pancreatic lipase. However, the possibility of synergies between the polyphenols cannot be disregarded.     

Total polyphenols,catechin profiles and antioxidant activity of tea products from purple leaf coloured tea cultivars

Black (aerated) and green (unaerated) tea products, processed from 10 green and 18 purple leaf coloured cultivars of Kenyan origin, and two tea products, from the Japanese cultivars, Yabukita and Yutakamidori, were assayed for total polyphenols (TP) content, individual catechin profiles and in vitro antioxidant capacity (AA). In addition, the phenolic content of the tea products was determined using the Folin–Ciocalteu phenol reagent. Catechin fractions were identified using reverse phase high performance liquid chromatography (HPLC) with a binary gradient elution system.The AA% of the tea products was determined using a 2,2′-diphenyl picrylhydrazyl (DPPH) radical assay method. The results showed that TPs, catechin profiles and antioxidant activities were significantly (p ? 0.05) higher in unaerated than in aerated teas. Tea products from the purple leaf coloured tea cultivars had levels of TPs, total catechin (TC) and antioxidant activities similar to those from the green leaf coloured cultivars, except for teas from the Japanese cultivars that were very low in the assayed parameters. Caffeine content was significantly (p ? 0.05) lower in products from the purple leaf coloured cultivars than in those from the green leaf coloured tea cultivars. Antioxidant activity (%) was higher in tea products from the Kenyan germplasm than in those from the Japanese cultivars. Antioxidant potency of tea products was significantly (r = 0.789⁷, p ? 0.01) influenced by the total anthocyanin content of the purple leaf coloured cultivars. Cyanidin-3-O-glucoside was the anthocyanin most highly correlated with AA% (r = 0.843⁷, p ? 0.01 in unaerated tea). Total catechins in the unaerated products from the green leaf coloured tea cultivars were also significantly correlated with antioxidant capacity (r = 0.818⁷, p ? 0.01). Results from this study suggest that the antioxidant potency of teas is dependent on the predominant flavonoid compound, the type of tea cultivar and the processing method.     

Green tea preparation and its influence on the content of bioactive compounds

The effect of different extraction conditions and storage time of prepared infusions on the content of bioactive compounds of green teas and their antioxidant capacity were investigated. The content of total phenols, total flavonoids and total non-flavonoids in green teas was determined spectrophotometrically, while 7 flavan-3-ols, 6 phenolic acids and 3 methylxanthines were identified and quantified by using high performance liquid chromatography (HPLC–PDA). Among the tested green teas bagged green tea Twinings of London was recognized as the richest source of phenolic compounds (3585 mg/L GAE of total phenols). The most abundant phenolic constituents of green tea were flavan-3-ols, of which EGCG was prevailing in all teas (94.54–357.07 mg/L). The highest content of caffeine, as the most abundant methylxanthine, was determined in powdered green tea. The findings of this investigation suggest that extraction efficiency of studied bioactive compounds from green tea depends on the extraction conditions and that maximum extraction efficiency is achieved during aqueous extraction at 80 °C, for 5′ (powder), 15′ (bagged) and 30′ (loose leaf). In order to determine the antioxidant capacity of teas the DPPH, ABTS and FRAP assays were applied. Regardless of the extraction conditions all green teas exhibited significant antioxidant capacity in vitro, which was in correlation with their phenolic content, confirming that green tea is one of the best dietary sources of antioxidants.     

Commercial peppermint (Mentha × piperita L.) teas: Antichlamydial effect and polyphenolic composition

The qualitative and quantitative polyphenolic contents in the infusions of the commercial peppermint tea (Mentha × piperita L.) samples (n = 27) from different countries were studied using HPLC–UV-MS/MS analysis. The most abundant polyphenolics in the peppermint infusion were eriocitrin, 12-hydroxyjasmonate sulfate, luteolin-O-rutinoside and rosmarinic acid. In order to evaluate the content of samples by finding chemosystematic markers, the essential oil composition was studied by GC. The analyses showed that the 24 (89%) peppermint tea samples contained peppermint, whereas three samples may contain Mentha spicata, different from that claimed on the package.The effects of seven peppermint tea extracts against respiratory tract pathogen Chlamydia pneumoniae were investigated in vitro. All seven selected tea extracts were active against C. pneumoniae, the growth inhibition ranging from 20.7% to 69.5% at extract concentration of 250 μg/ml. In most cases, the antichlamydial activity was related to the peppermint teas having also high content of luteolin and apigenin glycosides. This study supports the consumption of peppermint tea to potentially elicit beneficial health effects on acute respiratory tract infections.     

Mate tea-mediated reduction in catecholamine synthesis improves cutaneous wound healing of chronically stressed mice

Chronic stress stimulates oxidant production and oxidative damage which compromise cutaneous wound healing. Mate tea rich is in antioxidant compounds and may be a good alternative for treatment of oxidative diseases. Therefore, the aim of this study was to investigate the effects of supplementation with mate tea on cutaneous healing in stressed mice. Mice were submitted to rotational stress (ST) and treated with mate tea (MT) daily until euthanasia. An excisional lesion was created on each mouse and 4 or 10 days later, the lesions were analyzed. In addition, murine skin fibroblasts were exposed to elevated epinephrine (E) levels plus mate tea, and fibroblast activity was evaluated. In in vivo assays, the supplementation with mate tea inhibited the stress-induced increase in: catecholamine synthesis (ST: 23.3 ± 2.5; ST + MT: 18.0 ± 0.9 ng/μl, p < 0.05), carbonyl protein content (ST: 962.0 ± 35.6; ST + MT: 35.7 ± 8.9 nmol/μg protein, p < 0.05), lipid peroxide levels (ST: 18.5 ± 2.3; ST + MT: 11.8 ± 1.2 nmol/mg protein, p < 0.05), wound contraction (ST: 44 ± 4; ST + MT: 17 ± 2%, p < 0.05), re-epithelialization (ST: 908 ± 35; ST + MT: 2081 ± 138 μm, p < 0.05), transforming growth factor-β (ST: 5.0 ± 0.02; ST + MT: 1.3 ± 0.06 u.a., p < 0.05), and myofibroblast density (ST: 19 ± 2; ST + MT: 9 ± 1%, p < 0.05). Stress-induced reduction in the amount of macrophages (ST: 133 ± 19; ST + MT: 392 ± 33 cells, p < 0.05) and neutrophils (ST: 1161 ± 62; ST + MT: 1313 ± 103 cells, p < 0.05) and hydroxyproline levels (ST: 1.3 ± 0.2; ST + MT: 4.6 ± 0.9 ng/mg tissue, p < 0.05), and this was reversed by mate tea. In in vitro assays, the treatment with mate tea reversed the reduction in collagen deposition (E: 1.7 ± 0.3; E + MT: 3.7 ± 0.01 pixels, p < 0.05) and the increase in cell proliferation (E: 331 ± 2; E + MT: 203 ± 3% of control, p < 0.05), accumulation of lipid peroxides (E: 0.66 ± 0.009; E + MT: 0.55 ± 0.01 nmol/mg protein, p < 0.05), and increase of tenascin-C protein expression (E: 3.8 ± 0.004; E + MT: 3.4 ± 0.004 a.u., p < 0.05) induced by epinephrine. In conclusion, the supplementation with mate tea improves the cutaneous wound healing of chronically stressed mice.     

Comparison of the antioxidant capacity and the antimicrobial activity of black and green tea

Tea is a common beverage. The green tea is preferentially recommended for its strong antioxidant properties and also for its antimicrobial activity. The antioxidant capacities of 30 samples (black and green tea) were determined by the chemiluminescent Trolox equivalent antioxidant capacity (TEAC) determination. The average value of TEAC of the non-fermented (green tea) and semi-fermented tea samples was 1.43 mM and the average value of TEAC of the fermented teas (black tea) samples was 1.43 mM. All samples were stored in freezer (?20 °C) and the TEAC determination was repeated after a year. The average values of TEAC of non-fermented and semi-fermented tea samples were twofold lower in comparison to fermented tea samples and only 20% of average value of TEAC of the fresh tea infusion. The parallel determinations of minimal inhibitory concentration (MIC) on gram-positive and gram-negative bacterial strains (Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli) were done. Also the MIC was possible to determine after a year. The assumed prevailing antioxidant and antimicrobial activities of non-fermented tea infusions were not confirmed as well as the dominant antioxidant and antimicrobial properties of specific type of tea infusion.     

Investigation of the interaction between soluble antioxidants in green tea and insoluble dietary fiber bound antioxidants

This work investigates the possibility of interaction between insoluble dietary fiber bound antioxidants, specifically of wheat bran, and soluble antioxidants like those provide by aqueous infusions of green tea. Solutions of pure catechins were also assayed for comparison with those naturally found in tea. To accomplish this, the aqueous and alcohol soluble fractions as well as the lipid components of wheat bran were firstly removed and the freeze-dried insoluble residue was then treated with different concentrations of green tea infusions or aqueous solutions of epicatechin (EC) and epigallocatechin-3-gallate (EGCG) for certain time. Treatment with EC (0–200 μM) had no significant effect on the antioxidant capacity of insoluble bran fraction. However, treatment with EGCG significantly (p < 0.05) increased linearly the antioxidant capacity as a function of concentration (0–100 μM). Treatment with great tea infusions (1–3 g/100 ml) also increased the resulting antioxidant capacity of insoluble bran fraction, but the effect was lesser at higher infusion concentrations. Liquid chromatography couple to mass spectrometry (LC–MS) analyses of aqueous phases after treatment indicated comparable levels of decrease in the concentrations of catechins confirming their reaction with the radical forms of antioxidants bound to insoluble bran matrix.     

Characterization of the antioxidant functions of flavonoids and proanthocyanidins in Mauritian black teas

Tea drinking is associated with an improved antioxidant status in vivo which may contribute to the lowering of the risk of certain types of cancer, coronary heart disease and stroke. The polyphenolic bioactive composition and the antioxidant properties of Mauritian commercial black and fresh tea leaves were evaluated. Hot water infusates contained high levels of total phenols, total proanthocyanidins and total flavonoids. The concentrations of individual compounds, (+)-catechin, (−)-epicatechin, (−)-epicatechin 3-gallate, epigallocatechin, (−)-epigallocatechin 3-gallate, gallic acid, and procyanidin dimers B1 and B2 were high. The ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays were used to assess the antioxidant potential of tea infusates with the following order of potency: Ouvagalia tea > Buccaneer’s choice > Black Label > Red Label > Extra > Corson > Chartreuse > La Flora > 3-Pavillons. Linear regression analyses indicated high correlation coefficient with total proanthocyanidin (TEAC r = 0.96 and FRAP r = 0.95) and total phenol contents (TEAC r = 0.90 and FRAP r = 0.92) in infusates. Catechins and gallic acid significantly contributed to the overall antioxidant capacity of black tea extracts. In general, the fresh tea leaves had high levels of total phenols, total flavonoids, total proanthocyanidin and exhibited greater antioxidant potentials when compared with black teas. Thus Mauritian black teas and fresh tea leaves can be rich sources of polyphenolic compounds and antioxidants, which may be highly relevant to the maintenance of normal health and disease management, an observation that has led to the commencement of a clinical trial study to assess cardiovascular health in Mauritius.     

Relationship between photon emission and chemopreventive potential of tea

Photon emission from tea (610–670 nm) in the H₂O₂/KHCO₃/MeCHO system and the utility of the photon detection system in tea evaluation were investigated. Photon intensity of tea depended on manufacturing method as follows: green tea (1202 ± SD 173.51 cd/m²) > oolong tea (834 ± SD 237.44 cd/m²) > black tea (222 ± SD 87.65 cd/m²). Photon intensity corresponded with polyphenol content (r²=0.8810) rather than catechin content (r²=0.7759) and showed a high correlation with chemopreventive activities against H₂O₂ (r²=0.7516), O₂⁻ (r²=0.7998) and DPPH radical (r²=0.7516). Photon intensity from green tea leaves at each manufacturing process step gave the same decreasing curve as DPPH radical scavenging activity. Chemiluminescence of tea, which gives information on the polyphenol content and chemopreventive potential, is a useful technique for tea evaluation.     

Yerba mate tea (Ilex paraguariensis): Phenolics,antioxidant capacity and in vitro inhibition of colon cancer cell proliferation

Mate tea (MT) is a rich source of phenolic compounds that vary depending on geographical origin and mode of preparation. Total phenolic concentration and antioxidant capacity of Mate tea (Ilex paraguariensis) products were determined in this work. In addition, a representative MT was tested for in vitro inhibition of human colon carcinoma cell proliferation. Total polyphenol concentration, was measured using Folin–Ciocalteau method, ranged from 90 to 176 mg gallic acid eq (GAE)/g dry leaves (DL) in traditional MT and from 40 to 113 mg GAE/g DL in MT added with other flavouring ingredients. It was estimated that a cup of tea (250 ml) containing one teaspoon (5 g) of instant MT could provide an average intake of 1.5 g GAE. Fresh tea (FT) from Mate leaves displayed high antioxidant capacity (85 ± 1%) and preferentially inhibited 50% of net growth of human colorectal adenocarcinoma cells CaCo-2 (GI₅₀ = 1.0 ± 0.03 μg/ml) and HT-29 (GI₅₀ = 105.2 ± 15.2 μg/ml) when compared with the CCD-33Co normal colon fibroblast cell line (GI₅₀ > 300 μg/ml). MT inhibited in vitro colon cancer cell proliferation possibly mediated via pro-oxidant activities, therefore represents a potential source of chemopreventive agents that deserve further investigation.     

The protective effect of green and black teas (Camellia sinensis) and their identified compounds against murine sepsis

Several compound classes could be identified in the infusion of green tea (GTI) and black tea (BTI) from Camellia sinensis, mainly catechins and their gallate derivatives in GTI and their oxidation products, theaflavins and theasinensins, in BTI. We also managed to identify other components, such as proanthocyanidins, flavonoid glycosides, alkaloids, hydroxybenzoic and hydroxycinnamic acids and saponins. The infusions were fractionated and the ethyl acetate fractions [green tea ethyl acetate fraction (GEAF) and black tea ethyl acetate fraction (BEAF)] have concentrated the catechins, theaflavins and caffeine. So, the infusions, fractions and major compounds identified from both teas were assayed against murine sepsis, in order to assess whether they are effectively protecting from this pathology. The infusions at 70 mg/kg resulted in a decrease of sepsis mortality in 43% (GTI) and 40% (BTI), respectively. The ethyl acetate fractions were also efficient, allowing a survival rate of 50% (GEAF) and 66.6% (BEAF) at concentrations of 30 and 70 mg/kg, respectively. The main components from GEAF and BEAF were also assayed; epigallocatechin gallate (10 mg/kg), theaflavins (9 mg/kg) and caffeine (18 mg/kg) showed a survival rate of 50%, 40% and 20%, respectively. This protective effect can be explained, at least in part, by some of these compounds' ability to modulate some important inflammatory parameters, such as neutrophil influx, avoiding its accumulation in lungs, depletion of the pro-inflammatory cytokines (TNF-α and IL-6), increase the anti-inflammatory cytokine (IL-10) and, also, a significant decrease in tissue expression of iNOS and COX-2.     

Daily green tea extract supplementation reduces prothrombotic and inflammatory states in dialysis patients

Cardiovascular disease (CVD) remains the most common cause for excess morbidity and mortality in patients with chronic kidney disease (CKD) and end stage renal disease (ESRD) under chronic dialysis. ESRD patients have increased oxidative stress and endothelial dysfunction alongside increased levels of inflammation related proteins, which has prompted the exploration of anti-inflammatory and antioxidant treatments to improve outcomes. As green tea is increasingly well recognized for its antioxidant properties, we probed the effect of consumption of 1 capsule daily of green tea as a commercially available, decaffeinated green tea capsule (1 g, catechin content 68 mg) for 6 months on fibrinogen and inflammation in dialysis patients. Chronic hemodialysis patients (N = 25) were recruited and fibrinogen, FDP-D-dimer, high sensitivity (hs) CRP and the mononuclear cell protein expression of p22^phox, were assessed before, i.e. baseline and after 6 months of ingestion of 1 green tea capsule per day. After 6 months of daily green tea capsule ingestion, dialysis patients showed reduced protein expression of p22^phox (p < 0.0001), reduced hsCPR (p = 0.032) and fibrinogen (p = 0.022) levels and increased FDP-D-dimer (p = 0.0019) compared to their values at baseline. These results document lower oxidative stress and inflammation with green tea capsule ingestion and suggest a likely positive impact of green tea treatment on the atherosclerotic process of ESRD patients under dialysis.     

Effects of baking and aging on the changes of phenolic and volatile compounds in the preparation of old Tieguanyin oolong teas

A series of old oolong teas was prepared by baking fresh Tieguanyin oolong teas at 120–140 °C for 72 h, followed by a long-term storage of 5, 10 and 20 years. To monitor the chemical changes of the tea preparation, phenolic and volatile compounds in a fresh or its newly baked tea were analyzed and compared with those in the three aged teas. The contents of phenolic compounds in the teas were apparently altered by the baking, but remained relatively stable thereafter in the aging process. The contents of major catechin derivatives and flavonol glycosides presumably responsible for astringency and bitterness of teas were reduced while those of gallic acid and gallocatechin gallate, putatively originated from the decomposition and isomerization of (−)-epigallocatechin gallate, were elevated after baking. In contrast, linear and branched hydrocarbons, the abundant volatile compounds in the fresh tea, were relatively stable in the baking process, but nearly diminished during the long-term storage. Relatively minor contents of substituted benzaldehydes and pyrrole derivatives probably rendering the unique flavor of old oolong teas were generated after the baking and aging processes.     

Caffeinated and decaffeinated instant coffee consumption partially reverses high-fat diet-induced metabolic alterations in mice

Epidemiological data has associated coffee consumption with a lower prevalence of type 2 diabetes, metabolic syndrome and chronic liver disease. However, the mechanisms and coffee substances responsible for these effects remain unclear. In the present study, mice received caffeinated or decaffeinated instant coffee ad libitum during a two week period after inducing obesity by introducing a high-fat diet over a 10 week period. Body weight, glucose homeostasis, and liver and visceral adipose tissue inflammation were assessed. In addition, AKT signaling, the fatty acid profile and liver histopathological analyses were performed. Ingestion of caffeinated or decaffeinated coffee for 2 weeks resulted in reductions in glucose and insulin blood levels, and insulin tolerance was improved without reductions in final body weight or adiposity. Only caffeinated coffee modified the adipokine profile in visceral adipose tissue, resulting in a restoration of adiponectin levels. However, deleterious liver alterations, which manifested as reductions in steatosis, inhibition of iNOS expression and restoration of insulin inducing-AKT phosphorylation, were reversed by the ingestion of both caffeinated and decaffeinated coffee. Serum AST and ALT levels were also improved in mice after coffee ingestion, while the fatty acid profile in the liver and the cytokine profiles in adipose and liver tissues were not altered by coffee ingestion. Thus, instant coffee consumption reverses obesity-induced alterations in mice, and our results corroborate those of epidemiological studies that associated coffee consumption with a lower prevalence of obesity-related pathologies.     

Effect of pulsed electric field (PEF)-treated kombucha analogues from Quercus obtusata infusions on bioactives and microorganisms

Pulsed electric field (PEF) is a promising non-thermal food preservation technology. The objective was to study inactivation of yeasts in PEF-treated kombucha analogues prepared from Quercus obtusata infusions. Fermentation conditions of infusions from Q. obtusata were time (7 days), sugar (10%), starting culture (10%), and inoculum (2.5%, at 25 °C). The PEF treatment considered using square waves, an electric field strength (37.3–53.4 kV/cm), PEF processing time (445.3–1979.2 μs), an output temperature (18.31 ± 0.98 °C), an input energy (21.2 - 136.5 KJ/L), and two feed flow rates (51.42 and 102.85 L/h). pH, °Brix, color determinations, microbiological testing, total phenolic, flavonoid content, DPPH test, and UPLC/ESI/MS/MS analysis were done. No changes at different PEF conditions were observed for pH and °Brix. Higher color changes were observed at higher specific energies. Acid-acetic bacteria were more sensitive to PEF than yeasts. Lower specific energies render products with higher polyphenolic content and antioxidant capacity.Industrial relevancePulse electric field is an interesting alternative to preserve kombucha analogues from oak leave infusions with minimal changes in physicochemical characteristics, antioxidant activity and bioactive compounds. The present work describes the effect of feed flow and specific energy on the several characteristics of fermented beverages, determining conditions for best processing.     

Predicting success with silicone-hydrogel contact lenses in new wearers

Purposeto evaluate changes in tear metrics and ocular signs induced by six months of silicone-hydrogel contact lens wear and the difference in baseline characteristics between those who successfully continued in contact lens wear compared to those that did not.MethodsNon-invasive Keratograph, Tearscope and fluorescein tear break-up times (TBUTs), tear meniscus height, bulbar and limbal hyperaemia, lid-parallel conjunctival folds (LIPCOF), phenol red thread, fluorescein and lissamine-green staining, and lid wiper epitheliopathy were measured on 60 new contact lens wearers fitted with monthly silicone-hydrogels (average age 36 ± 14 years, 40 females). Symptoms were evaluated by the Ocular Surface Disease Index (OSDI). After six months full time contact lens wear the above metrics were re-measured on those patients still in contact lens wear (n = 33). The initial measurements were also compared between the group still wearing lenses after six months and those who had ceased lens wear (n = 27).ResultsThere were significant changes in tear meniscus height (p = 0.031), bulbar hyperaemia (p = 0.011), fluorescein TBUT (p = 0.027), corneal (p = 0.007) and conjunctival (p = 0.009) staining, LIPCOF (p = 0.011) and lid wiper epitheliopathy (p = 0.002) after six months of silicone-hydrogel wear. Successful wearers had a higher non-invasive (17.0 ± 8.2 s vs 12.0 ± 5.6 s; p = 0.001) and fluorescein (10.7 ± 6.4 s vs 7.5 ± 4.7 s; p = 0.001) TBUT than drop-outs, although OSDI (cut-off 4.2) was also a strong predictor of success.ConclusionSilicone-hydrogel lenses induced significant changes in the tear film and ocular surface as well as lid margin staining. Wettability of the ocular surface is the main factor affecting contact lens drop-out.     

Short communication: Relationship between metabolic status and the milk concentrations of haptoglobin and lactoferrin in dairy cows during early lactation

To investigate the relationship between metabolic status and the acute phase proteins haptoglobin (Hp) and lactoferrin (Lf) in milk, the concentrations of β-hydroxybutyrate (BHBA), nonesterified fatty acids (NEFA) and Hp were determined in blood samples collected weekly from 4 wk prepartum until 12 wk postpartum. Haptoglobin and Lf were determined in weekly milk samples. The cows (n = 49) were retrospectively classified according to NEFA and BHBA concentrations using different time intervals and threshold values for NEFA and BHBA, respectively. For BHBA, 4 threshold concentrations, (0.8, 1.0, 1.2, and 1.6 mM) were evaluated either at the first week before calving, at wk 1 or 2 postpartum, or when considering the means of wk 2 and 3 postpartum. For NEFA, the tested thresholds were 0.5 and 0.6 mM at wk 1 prepartum, wk 1 or 2 postpartum, or the means of wk 1 and 2 postpartum. All variables showed changes during the interval of observation. Comparing the time course of the acute phase proteins in the subgroups classified according to BHBA or NEFA, consistently greater concentrations of Hp in serum and milk and of Lf in milk were observed in those animals with BHBA concentrations above 1.6 mM during the last week before calving (n = 3/47) than in those with BHBA concentrations below this threshold. For NEFA, analogous differences for Hp in both serum and milk (0.52 ± 0.07 and 18.1 ± 4.6 for NEFA >0.6 mM vs. 0.36 ± 0.04 mg/mL and 8.46 ± 1.63 &micro;g/mL for NEFA <0.6 mM, respectively) and for Lf in milk (130 ± 8.5 vs. 89.2 ± 7.1 &micro;g/mL, respectively) were detected when a threshold of 0.6 mM at wk 2 postpartum was used. Our results indicated that cows having BHBA and NEFA serum concentrations above these thresholds at defined times could be identified.     

Purification and partial characterisation of X-prolyl dipeptidyl aminopeptidase of Lactobacillus helveticus ITG LH1

A X-prolyl dipeptidyl aminopeptidase (EC 3.4.14.5, XPDAP) from Lactobacillus helveticus ITG LH1, a strain used for Swiss-type cheese, was purified by ion exchange and affinity chromatographies. The enzyme appeared to be a 140 kDa monomer. Optimal activity occurred at pH 7 and 40°C, but it was rapidly inactivated above 50°C. The enzyme was activated by NaCl and KCl up to 50–200 mm but its activity levelled off at higher salt concentrations. Its complete inhibition was caused by 0.1 mm HgCl₂, 1 mm SnCl₂ and 2.5 mm CuCl₂. It was inactivated by reagents specific for serine proteases, such as phenylmethylsulfonyl fluoride and sulfhydryl group-blocking reagents. The enzyme hydrolysed p-nitroanilide-substituted X-Pro and X-Ala dipeptides, as well as β-casomorphin 1-4.