Critical role of superoxide anions and hydroxyl radicals in HEMA-induced apoptosis.

OBJECTIVE: Resin monomers such as 2-hydroxyethyl methacrylate (HEMA) induce apoptosis because of the excess formation of reactive oxygen species (ROS). The portion of ROS including superoxide anions, hydrogen peroxide or hydroxyl radicals in monomer-induced apoptosis is unknown. Here, the effectiveness of superoxide anions or hydroxyl radicals was analyzed using tempol or sodium formate as radical scavengers. METHODS: RAW264.7 mouse macrophages were exposed to HEMA (0-6-8mM) in the presence of tempol (0-0.05-0.5-5.0mM) or sodium formate (0-1-5-10mM). The formation of ROS using DCFH2-DA or dihydrorhodamine 123 (DHR123) as fluorescent dyes and the induction of apoptosis was determined by flow cytometry after 1h or 24h exposure periods. Expression of enzymes related to ROS metabolism was detected by Western blotting. RESULTS: DCF fluorescence significantly increased after short exposure (1h) while DHR123 fluorescence was enhanced after a long exposure period (24h) in cells treated with HEMA. Although no influence was detected on the formation of ROS, tempol or sodium formate protected cells from HEMA-induced apoptosis. The number of cells in late apoptosis or necrosis induced with 6 or 8mM HEMA was reduced in the presence of tempol or low concentrations of sodium formate. HEMA-induced expression of catalase, indicating oxidative stress, decreased in the presence of tempol. SIGNIFICANCE: Superoxide anions and hydroxyl radicals contribute to HEMA-induced apoptosis. The current findings support the development of strategies based on the pharmacological inhibition of enzymes producing superoxide anions finally converted to hydroxyl radicals to compensate for potential adverse tissue reactions associated with dental composites.

Differential rumination, intake, and enteric methane production of dairy cows in a pasture-based automatic milking system.

Proper performance monitoring of cows on pasture-based diets is crucial to inform nutritional recommendations that minimize undesirable effects of high ruminant CH4 emissions into the environment. The prediction of linkages between rumination patterns, methane emissions, and correlated production traits of cows in a pasture-based automatic milking system was tested. A previous 10-d baseline measurement of rumination activity by acoustic methodology of 156 Holstein-Friesian cows was used for frequency analysis of rumination time and identification of 2 treatment groups (n = 37 cows/group) represented by cows with consistently high (HR; 75th rumination percentile = 617.55 ± 81.37 min/d) or low (LR; 25th rumination percentile = 356.65 ± 72.67 min/d) rumination. The HR and LR cows were paired by nearest parity, days in milk, body weight (BW), and previous 10-d milk production, and within pairs randomly assigned to 1 of 2 experimental groups managed on a voluntary milking system with diets consisting of at least 75% pasture, plus concentrates. Animal traits, including rumination time, mass flux of CH4 (QCH4) and carbon dioxide (QCO2), milk production, and estimated dry matter intake according to individual QCO2 fluxes over a 22-d period were analyzed with repeated measure mixed models for a completely randomized design, structural equation modeling, and nonlinear regression. High rumination and methane was seen in older and heavier cows that had greater estimated dry matter intake and milk production. A consistent difference in rumination time and QCH4 across days was detected between HR and LR, even after adjustment for metabolic BW. Estimated dry matter intake had direct positive effects on rumination and QCH4, but no independent direct effect of rumination on QCH4 was detected. The LR cows produced more QCH4/milk, associated with lower milk, BW, concentrate intake, and greater activity at pasture. A typical dilution of maintenance effect on QCH4/milk was detected as a consequence of increasing milk yield and similar significant reduction of QCO2/milk. The results raise challenging questions regarding the rumination patterning of grazing dairy cows and alternatives to reduce ruminant methane emissions in grazing dairy cows.

Evaluation of the Brix refractometer as an on-farm tool for the detection of passive transfer of immunity in dairy calves.

OBJECTIVES: To investigate the accuracy of both the optical and digital Brix refractometers compared with radial immunodiffusion (RID) for determining the immunoglobulin G (IgG) concentrations in dairy calf serum. DESIGN: The experiment design was a cross-sectional survey of four dairy farms. Serum was sampled from 12 calves from each farm at approximately 48 hours of age. METHODS: Serum IgG concentrations of 48 calves were measured using RID and both types of Brix refractometer. RESULTS: IgG concentrations measured by Brix refractometer scores correlated with RID results: 0.74 and 0.71 for the digital and optical devices, respectively. The minimum Brix score that identified calf serum with success of passive immunity (>1000 mg/dL RID IgG) with 100% accuracy was 10% for both devices. The optical and digital devices performed similarly at identifying IgG concentrations in calf serum, with a concordance of 87%. CONCLUSION: Brix refractometer score ≥10% can be used to classify calves with successful transfer of passive immunity and the devices are sufficiently accurate for use as a simple, inexpensive on-farm tool for the monitoring of neonatal dairy calf immunity levels.

[Autologous thrombocyte administration in treatment of idiopathic macular foramen]. / Autologe Thrombozytenapplikation bei der Behandlung des idiopathischen Makulaforamens.

BACKGROUND: Recent studies have shown the usefulness of pars plana vitrectomy with the use of growth factors in the treatment of macular holes. Autologous platelet concentrates contain many growth factors to stimulate glial wound healing. PATIENTS: Nineteen patients with idiopathic macular hole underwent vitrectomy, membrane peeling, air injection and installation of autologous platelet concentrate (0.1 ml). The platelet concentrate contained a mean of 1.8 x 10(9) platelets/ml. RESULTS: The anatomic success rate in stage 2 macular hole was 100%, in stage 3, 82% and in stage 4, 50%. Visual acuity improved in all patients with stage 2 (two lines) and in 73% of stage 3 at least (one line). CONCLUSION: Platelets are effective in the treatment of macular holes due to the high amount of different growth factors (PDGF, EGF, bFGF, IGF-1) which have a high affinity binding to Müller cells helping to seal the hole by photoreceptor adaption.

Influence of suction cup oculopression on corneal astigmatism.

In 11 (right) eyes of 11 ocularly healthy subjects an artificial stepwise intraocular pressure (IOP) elevation was applied by suction cup oculopression. The initial negative pressure in the suction cup was 80 mmHg; it was raised in steps of 40 mmHg. The median of the corneal astigmatism, measured with a Zeiss ophthalmometer, was 0.50 D before oculopression (the values of the 10th and 90th percentiles were 0.30 and 1.10 D, respectively). Corneal astigmatism increased to 2.00 (0.00-5.10) D, 2.25 (1.00-5.55) D, 2.63 (0.63-7.00) D, 3.38 (1.88-6.88) D, 3.38 (2.83-7.25) D, and 4.38 (2.85-5.63) D with 80, 120, 160, 200, 240, and 280 mmHg oculopression, respectively. The astigmatism dropped to 0.75 (0.00-2.30) D immediately after removal of the suction cup. Thus, suction cup oculopression not only influenced IOP but also ocular refraction. This is of particular importance since visual evoked potential (VEP) amplitude is to a high degree dependent on refractive changes. This fact has to be considered if changes in VEP amplitude during suction cup oculopression are used as a tolerance test in glaucoma diagnosis.

[Eye-pressure tonometry in prevention of glaucoma]. / Okulopressionstonometrie (OPT) in der Glaukompraxis.

Oculo-pression tonometry (OPT) was introduced in 1984 as a clinical method of examining ocular hydrodynamics. The method involves measuring intraocular pressure (IOP) by applanation tonometry performed before, during and after application of a pressure load that disturbs the dynamic balance between aqueous production and aqueous outflow. From the IOP before (P0) and immediately after (Pr0) the 8-min pressure load period, the outflow facility C(u) can be calculated: [formula: see text] The examinations performed so far have shown that (1) reduced outflow facility can be detected by OPT with a high degree of reliability, and (2) reduced outflow facility is always preceded by the development of glaucoma damage to the optic nerve head. A prospective study has shown that in the group of patients with reduced outflow facility but without glaucoma damage, 73% developed glaucoma damage with typical changes of the papilla and visual field within 3-7 years after the first examination.