Anisotropic stiffness and tensional homeostasis induce a natural anisotropy of volumetric growth and remodeling in soft biological tissues

Biomechanics and Modeling in Mechanobiology - Growth in soft biological tissues in general results in anisotropic changes of the tissue geometry. It remains a key challenge in biomechanics to...     

A stereological study of the effects of mercury inhalation on the cerebellum

Mercury in the environment that arises from organic and inorganic sources can cause irreversible damage to the nervous system. Toxicity may be direct or may arise from interactions with other metals in the environment. We evaluated the possible effects of mercury vapor on rat cerebellum. Twelve adult female rats were divided into control and experimental groups. The rats in the experimental group were exposed to mercury vapor for 9 h/day for 45 days. Cerebellar tissue samples were evaluated using stereology and for histopathology. The total number of Purkinje cells was estimated using a physical disector method. We found that in the experimental group, overall volume decreased and the number of Purkinje cells was reduced. We also found cellular damage including pycnotic nuclei, eosinophilic cytoplasm and vacuolization; these features were absent in the control group. We found that chronic exposure to inorganic mercury vapor is toxic to the cerebellum.     

Expression of ASC in renal tissues of familial mediterranean fever patients with amyloidosis: postulating a role for ASC in AA type amyloid deposition

Familial Mediterranean fever (FMF) is characterized by recurrent attacks of fever and serositis; in some cases, ensuing amyloidosis results in kidney damage. Treatment with colchicine reduces the frequency and severity of FMF attacks and prevents amyloidosis, although the mechanisms behind these effects are unknown. Pyrin, the protein product of the MEFV gene, interacts with ASC, a key molecule in apoptotic and inflammatory processes. ASC forms intracellular speck-like aggregates that presage cell death. Here we show that cell death after ASC speck formation is much slower in nonmyeloid cells than in myeloid cells. Additionally, we demonstrate that colchicine prevents speck formation and show that specks can survive in the extracellular space after cell death. Because we also found that ASC is expressed in renal glomeruli of patients with FMF but not in those of control patients, we posit that high local ASC expression may result in speck formation and that specks from dying cells may persist in the extracellular space where they have the potential (perhaps in association with pyrin) to nucleate amyloid. The fact that speck formation requires an intact microtubule network as shown here could potentially account for the ability of prophylactic colchicine to prevent or reverse amyloidosis in patients with FMF.     

Optimization of Bacillus subtilis natto growth parameters in glycerol-based medium for vitamin K (Menaquinone-7) production in biofilm reactors

Bioprocess and Biosystems Engineering - Menaquinone-7 (MK-7) is the key form of vitamin K used as a dietary supplement and its production revolves around Bacillus subtilis natto. Current...     

Application of next-generation sequencing methods for microbial monitoring of anaerobic digestion of lignocellulosic biomass

The anaerobic digestion of lignocellulosic wastes is considered an efficient method for managing the world’s energy shortages and resolving contemporary environmental problems. However, the recalcitrance of lignocellulosic biomass represents a barrier to maximizing biogas production. The purpose of this review is to examine the extent to which sequencing methods can be employed to monitor such biofuel conversion processes. From a microbial perspective, we present a detailed insight into anaerobic digesters that utilize lignocellulosic biomass and discuss some benefits and disadvantages associated with the microbial sequencing techniques that are typically applied. We further evaluate the extent to which a hybrid approach incorporating a variation of existing methods can be utilized to develop a more in-depth understanding of microbial communities. It is hoped that this deeper knowledge will enhance the reliability and extent of research findings with the end objective of improving the stability of anaerobic digesters that manage lignocellulosic biomass.     

Does the platelet-activating factor affect the antioxidant defense system?

The platelet-activating factor (PAF) is an inflammatory mediator and it may exert some of its effects by reactive oxygen species (ROS). We investigated the effects of PAF and hyperbaric oxygenation (HBO) on copper (Cu) and zinc (Zn) levels in plasma and the intracellular antioxidant enzyme activities of rats. PAF administration caused a decrease in erythrocyte catalase (CAT) and glutathione peroxidase (GPx) activities and in the plasma zinc level. Following PAF administration, exposure to HBO also caused a decrease in erythrocyte GPx activity. These results support the hypothesis that PAF may produce free oxygen radicals and HBO enhances this effect. The enzyme activities of the antioxidant defense system were found to be affected by these oxidative processes. This is likely to be the result of excessive production of ROS or overutilization and/or inhibition of the antioxidant enzymes.     

Protective Effects of Antioxidants Against Cadmium-induced Oxidative Damage in Rat Testes

The protective effects of melatonin, vitamin E, and selenium alone or in combination were tested against cadmium-induced oxidative damage in rat testes. A total of 60 male rats were equally divided into five study groups, one of which acted as control receiving subcutaneous injections of physiological saline. The remaining four groups were treated with subcutaneous injections of cadmium chloride at a dose of 1 mg/kg weight. The first study group received no treatment. The second group was treated with a combination of 60 mg/kg vitamin E and 1 mg/kg sodium selenite. Group 3 was treated with 10 mg/kg melatonin, and the fourth group received a combination of vitamin E, sodium selenite, and melatonin at the doses mentioned above. After 1 month, the animals were killed, and the testes were excised for histological inspection and determination of tissue malondialdehyde and the activity of superoxide dismutase. The animals receiving no treatment showed significantly higher malondialdehyde levels and reduced activity of the enzyme (p < 0.05). Treatment with antioxidants resulted in a significant reduction in malondialdehyde when compared to the nontreated animals (p < 0.05) and an increase in the superoxide dismutase activity that was almost the same as the controls. The combination of melatonin, vitamin E, and selenium appears to have the more profound effect against cadmium-induced testicular injury.