Carbon Dynamics of Prairie Ecosystems

This study analyzes carbon cycle processes in prairie environments, with the goal of determining carbon sequestration (containment) capacity of prairies of varying quality. Results of the study will be used to aid in recommendations to land managers regarding ideal landscapes for prairie restoration and conservation, in order to mitigate atmospheric greenhouse gas concentrations. We incorporate scientific fieldwork, lab procedures, and data entry and analysis. Our research team analyzed soil respiration gas samples, soil samples, and above- and belowground biomass samples to quantify carbon emissions and retention. Additionally, terrain analyses are being conducted based on topographic and GPS measurements to determine optimal spatial orientation (i.e., slope, elevation, and exposure). Field research is conducted at Nachusa Grasslands, and in order to compare the carbon processes of prairies in two development stages, we chose one plot which was well-established and of high quality and one which was more recently restored and of poorer quality. We installed PVC rings in a grid-like formation across each plot, and used these to collect soil respiration gas samples for carbon dioxide, methane, and nitrogen analysis. Additional data collection included extraction of soil cores from the immediate vicinity of each PVC ring for belowground biomass and soil bulk density analyses; and collection of vegetation in close proximity to each ring for aboveground biomass analysis. All the data is currently being input into a GIS and analyzed in combination to determine optimal prairie conditions for carbon sequestration.B.A. (Bachelor of Arts

Functional characterization of orbicularis oculi and extraocular muscles

The orbicularis oculi are the sphincter muscles of the eyelids and are involved in modulating facial expression. They differ from both limb and extraocular muscles (EOMs) in their histology and biochemistry. Weakness of the orbicularis oculi muscles is a feature of neuromuscular disorders affecting the neuromuscular junction, and weakness of facial muscles and ptosis have also been described in patients with mutations in the ryanodine receptor gene. Here, we investigate human orbicularis oculi muscles and find that they are functionally more similar to quadriceps than to EOMs in terms of excitation-contraction coupling components. In particular, they do not express the cardiac isoform of the dihydropyridine receptor, which we find to be highly expressed in EOMs where it is likely responsible for the large depolarization-induced calcium influx. We further show that human orbicularis oculi and EOMs express high levels of utrophin and low levels of dystrophin, whereas quadriceps express dystrophin and low levels of utrophin. The results of this study highlight the notion that myotubes obtained by explanting satellite cells from different muscles are not functionally identical and retain the physiological characteristics of their muscle of origin. Furthermore, our results indicate that sparing of facial and EOMs in patients with Duchenne muscular dystrophy is the result of the higher levels of utrophin expression

Evaluation of Bicanalicular Nasolacrimal Duct Intubation as an Adjunct in Surgical Ectropion Correction.

Background and Objectives: We aimed to analyze and compare the outcomes of conventional ectropion surgery procedures with and without concurrent bicanalicular nasolacrimal duct intubation to identify if the combination of procedures could serve as a novel surgical approach to treat lower eyelid ectropion. Materials and Methods: A retrospective review of all patients who underwent surgical correction for lower eyelid ectropion at the Cantonal Hospital of Aarau between January 2019 and December 2020 was performed. Patient medical records were examined for etiology, surgical correction technique and intra- and postoperative complications. The postoperative punctal position, the pre- and postoperative epiphora and reoperation rate were also documented. Two study groups consisting of cases with isolated and combined procedures were compared, with respect to postoperative punctual and lower lid position. Results: A total of 53 lower eyelids (35 patients) were included in this study. Six months postoperatively, the correct punctum position (p = 0.1188) and improvement of epiphora (p = 0.7739) did not significantly differ between the two groups. More complications were seen in the nasolacrimal duct intubation group (p = 0.0041), which consisted of cheese wiring and one tube dislocation. Conclusion: In our study, bicanalicular nasolacrimal intubation during ectropion surgery does not seem to improve the outcome of ectropion surgery and is, therefore, not recommended on a routine basis

Ocular penetration of caspofungin in a rabbit uveitis model

Background: Little is known about the ocular penetration of echinocandin antifungals. We studied the ocular distribution of systemically administered caspofungin in a rabbit uveitis model. Methods: Caspofungin (1mg/kg per day) was given intravenously to rabbits as a single dose or as repeated daily doses on 7days starting 24h after induction of unilateral uveitis by intravitreal endotoxin injection. Caspofungin concentrations were determined by high-performance liquid chromatography in the cornea, aqueous humor, vitreous humor, and serum 4, 8, 16, and 24h after administration of a single dose and 24h after the last of seven doses. Results: The mean caspofungin concentration in the aqueous of the inflamed eye 4 and 8h after single-dose administration was 1.30 ± 0.39μg/ml and 1.12 ± 0.34μg/ml, respectively. Drug concentrations decreased to 0.24 ± 0.09μg/ml at 16h and 0.26 ± 0.14μg/ml at 24h. In the vitreous of inflamed eyes drug levels were undetectable at all time points. No drug was found in the aqueous of inflamed eyes 24h after the last of seven repeated doses, and the vitreous only contained trace amounts. In the corneas of inflamed eyes concentrations reached 1.64 ± 0.48μg/g at 4h, peaked at 2.16 ± 1.14μg/g at 8h, and declined to 1.87 ± 0.52μg/g and 1.49 ± 0.48μg/g at 16and 24h, respectively. After repeated dosing, corneal concentrations of caspofungin were 0.8 and 1.0μg/g and below the limit of detection in two of four animals. In non-inflamed eyes no drug was detectable in the aqueous and vitreous humor, and the corneas at any time point. Conclusions: In our model, caspofungin reached therapeutically relevant levels in the aqueous and cornea but not in the vitreous humor of inflamed eyes. Intraocular drug deposition was critically dependent on a disrupted blood-eye barrier. These findings suggest a limited role for caspofungin in the treatment of fungal endophthalmiti

Tocotrienol inhibits proliferation of human Tenon's fibroblasts in vitro: a comparative study with vitamin E forms and mitomycin C

Purpose: To evaluate the potential of the vitamin E compound α-tocotrienol as antifibrotic agent in vitro. Methods: Using human Tenon's capsule fibroblast cultures, the antiproliferative and cytotoxic effects of the different vitamin E forms α-tocopherol, α-tocopheryl acetate, α-tocopheryl succinate and α-tocotrienol were compared with those of mitomycin C. To mimic subconjunctival and regular oral application in vivo, exposure time of serum-stimulated and serum-restimulated fibroblasts (SF and RF, respectively) to vitamin E forms was set at 6 days. Cultures were only exposed for 5min to mitomycin C due to its known acute toxicity and to mimic the short-time intraoperative administration. Proliferation (expressed as % of control) was determined by DNA content quantification on days 2, 4 and 6, whereas cytotoxicity was assessed by cell morphology and glucose 6-phosphate dehydrogenase (G6PD) release after 24h. Results: α-Tocopherol and α-tocopheryl acetate stimulated growth of SF, but not RF. Reduction of fibroblast content by α-tocopheryl succinate was accompanied by increased G6PD release and necrosis. Contrary to α-tocopheryl succinate, 50μM or repeatedly 20μM of α-tocotrienol significantly inhibited proliferation without causing cellular toxicity (maximal effect: 46.8%). RF were more sensitive to this effect than SF. Mitomycin C 100-400μg/ml showed a stronger antiproliferative effect than α-tocotrienol (maximal effect: 13.8%). Morphologic characteristics of apoptosis were more commonly found under treatment with mitomycin C. Conclusions: Of the vitamin E forms tested, only α-tocotrienol significantly inhibited growth at non-toxic concentrations. In this in vitro study, antiproliferative effects of mitomycin C were stronger than those of α-tocotrieno