Homogenized constrained mixture models for anisotropic volumetric growth and remodeling

Constrained mixture models for soft tissue growth and remodeling have attracted increasing attention over the last decade. They can capture the effects of the simultaneous presence of multiple constituents that are continuously deposited and degraded at in general different rates, which is important to understand essential features of living soft tissues that cannot be captured by simple kinematic growth models. Recently the novel concept of homogenized constrained mixture models was introduced. It was shown that these models produce results which are very similar (and in certain limit cases even identical) to the ones of constrained mixture models based on multi-network theory. At the same time, the computational cost and complexity of homogenized constrained mixture models are much lower. This paper discusses the theory and implementation of homogenized constrained mixture models for anisotropic volumetric growth and remodeling in three dimensions. Previous constrained mixture models of volumetric growth in three dimensions were limited to the special case of isotropic growth. By numerical examples, comparison with experimental data and a theoretical discussion, we demonstrate that there is some evidence raising doubts whether isotropic growth models are appropriate to represent growth and remodeling of soft tissue in the vasculature. Anisotropic constrained mixture models, as introduced in this paper for the first time, may be required to avoid unphysiological results in simulations of vascular growth and remodeling.     

Effect of retinyl acetate on transglutaminase 2 activity in carcinogen treated rat liver

Transglutaminase 2 (TG2) has been implicated in wound healing, cellular differentiation, apoptosis and cell survival. TG2 activity increases following acute and chronic liver injury; however, the role of TG2 in tumors, is controversial. TG2 is a retinoid-inducible enzyme. We investigated the effects of retinyl acetate (RA) on the activity and levels of TG2 during the initiation and promotion stages of liver cancer. p-Dimethylaminoazobenzene (p-DAB) was used as initiator and 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) was used as promoter in our model of carcinogenesis. Rats were divided into four groups of 24: control, corn oil control, p-DAB + TCDD, and p-DAB + TCDD + RA. Six rats from each group were sacrificed at days 30, 60, 90 and 120. TG2 activity decreased in the p-DAB + TCDD treated group, but TG2 immunostaining scores did not change by days 90 and 120. Neither TG2 enzyme activity nor the immunostaining score of TG2 protein changed in the tissues of the p-DAB + TCDD + RA group by days 90 and 120. TG2 activity was not be ameliorated by RA during the initiation or promotion stages of carcinogen induced liver cancer.     

Prolific shoot regeneration from immature embryo explants of sainfoin (Onobrychis viciifolia Scop.)

Summary Immature cotyledons and embryo axes of sainfoin were cultured on Murashige and Skoog (MS) media supplemented with various concentrations of 6-benzylaminopurine (BAP) and a-naphthaleneacetic acid (NAA) to induce adventitious shoot regeneration. The highest frequency of shoot regeneration occurred following an initial callus growth on a MS medium containing 0.5 mg/l BAP and 2 mg/l NAA. Immature embryo axes showed higher regeneration capacity than immature cotyledons, however, shoot elongation was best achieved on immature cotyledons. Regenerated shoots were excised and rooted in half strength MS medium with 1 mg/l indole-butyric acid (IBA) or 1 mg/l NAA. The rooted plantlets were finally transferred to compost.     

Plasma selenium levels in rheumatoid arthritis

The plasma selenium (Se) levels were determined in patients with rheumatoid arthritis (RA) and healthy controls. Plasma Se levels in 60 patients were found to be significantly lower than those in 60 normal, healthy controls (p<0.001). Similar significant differences were determined in sex-matched comparisons between patients and controls (p<0.001) but there was no significant difference in plasma Se levels in sex-matched comparisons in both groups (p>0.05). Our results suggest that Se is an important factor in RA.     

Evaluation of cytotoxic,antifungal, and larvicidal activities of different bis-sulfonamide Schiff base compounds

Schiff bases (imines or azomethines) are versatile ligands synthesized from the condensation of amino compounds with active carbonyl groups and used for many pharmaceutical and medicinal applications. In our study, we aimed to determine the cytotoxic, antifungal and larvicidal activities of biologically potent bis-sulfonamide Schiff base derivatives that were re-synthesized by us. For this aim, 16 compounds were re-synthesized and tested for their cytotoxic, antifungal and larvicidal properties. Among this series, compounds A1B2 , A1B4 , A4B2 , A4B3 , and A4B4 were shown to have cytotoxic activity against tested cancer lung cell line (A549). The most potent antifungal activity was observed in compounds A2B1 and A2B2 against all fungi. A1B1 showed the strongest larvicidal effect at all concentrations at the 72nd h (100% mortality). These obtained results demonstrate that these type of bis-substituted compounds might be used as biologically potent pharmacophores against different types of diseases.     

A note on the brine shrimp Artemia in Tuz Lake (Turkey)

Population density, fecundity andreproduction period of Artemia sp. in TuzLake, Turkey, beside environmental factors, such as oxygen,temperature, salinity, pH and electrical conductivity werestudied during 1993 and 1994.Artemia sp. occurred at two stations at the coast.Overwintering cysts hatched in early May, when the population was composed of 90% metanauplii (93%at Y4 and 99% at Y5) and few adult females. Peak abundanceoccurred in late May, at 106to 114 ind.m^–3.     

Effects of different Rhododendron control methods in eastern beech (Fagus orientalis Lipsky) ecosystems in the western Black Sea region of Turkey

Intensive weed control and plot preparation practices have become a critical and integral part of productive beech forest management in Turkey’s coastal Black Sea region (BSR). This study was conducted in an eastern beech forest of 100+ year old in the BSR to evaluate ecosystem effects of three different experimental Rhododendron ponticum understory control methods with a randomised block design, including manual grubbing, foliar and cut stump spraying with imazapyr (Arsenal) and foliar and cut stump spraying with triclopyr (Garlon). Untreated vegetation plots served as controls. Evaluation of these treatments included their effects on understory and forest floor biomass and nutrients (C, N, P, S, K, Ca and Mg) and effects on soils, including bulk density, pH, soil nutrients (C, N, P and S), exchangeable cations (K, Ca and Mg) and soil cation exchange capacity (CEC). Grubbing and imazapyr treatments had greatly reduced the amount of understory biomass 5 years after application (P = 0.002). Triclopyr treatment also had a major effect on understory vegetation control, but by 5 years later, about 10% of the rhododendron originally present on these plots had gradually re‐sprouted and partially covered the plots. Five years after woody vegetation control treatments, at the 0‐ to 20‐cm depth, treatments did not appear to affect soil bulk density, pH and CEC. For the upper 20‐cm soil depth, the exchangeable soil K concentration at the 10‐ to 20‐cm depth on triclopyr‐treated plots was 33% higher than on grubbing plots, and it was twice that of imazapyr application plots. Imazapyr plots had almost 11 times more dead organic matter on the forest floor than there was on grubbing plots. Forest floor C concentrations on imazapyr plots were 26 and 14% greater than those on grubbing and triclopyr plots, respectively. Total ecosystem (forest floor + understory + soil exchangeable) Ca content was 50% higher on imazapyr plots than that on triclopyr plots, while the ecosystem K pool on imazapyr treatment plots was 27% lower than that on triclopyr plots. Herbicides can be used as an alternative for achieving some forest management objectives when other vegetation control methods are not feasible or economical. It is recommended that vegetation control not be used on steep slopes because of greater risk of soil erosion. There may be benefits in encouraging slash disposal by fire after imazapyr treatments, thus removing recalcitrant understory residues left on the forest floor and releasing the essential nutrients within them.     

Profiling of molecular interactions in real time using acoustic detection

Acoustic sensors that exploit resonating quartz crystals to directly detect the binding of an analyte to a receptor are finding increasing utility in the quantification of clinically relevant analytes. We have developed a novel acoustic detection technology, which we term resonant acoustic profiling (RAP). This technology builds on the fundamental basics of the "quartz crystal microbalance" or "QCM" with several key additional features including two- or four-channel automated sample delivery, in-line referencing and microfluidic sensor 'cassettes' that are pre-coated with easy-to-use surface chemistries. Example applications are described for the quantification of myoglobin concentration and its interaction kinetics, and for the ranking of enzyme-cofactor specificities.     

Cisplatin cytotoxicity is enhanced with zoledronic acid in A549 lung cancer cell line: preliminary results of an in vitro study

We tested whether zoledronic acid, a biphosphonate with proposed apoptotic activity, augmented the cytotoxicity of cisplatin and/or gemcitabine in A549 lung cancer cell line. This cell line was subjected to different concentrations of the above chemotherapeutic agents and zoledronic acid. Cytotoxicity was assessed by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide) assay. Particularly, zoledronic acid in 100 micromolar (microM) concentration augmented the cytotoxicity by cisplatin 1microg/ml from 25% to 70% (Z=3.22, P=0.0072). A significant portion of cells underwent apoptosis with or without zoledronic acid, but more so with the combination treatment as assessed by an Annexin V-FITC apoptosis detection kit. However, 100microM zoledronic acid showed 50% cytotoxicity on its own, but failed to improve cytotoxicity by Gemcitabine. Thus, we show for the first time in a lung cancer cell line that zoledronic acid bears cytotoxic potential on its own and in conjunction with cisplatin. The clinical potential of this finding should be further studied.