Coxites zubairensis Smout, 1956: a new record from Late Cenomanian of the Southern Galala Plateau,Egypt

Coxites zubairensis Smout 1956 is documented from the upper Cenomanian Galala Formation, Umm Khayshar stratigraphic section, Southern Galala Plateau, Eastern Desert, Egypt, and treated systematically.     

The effects of isoniazid on hippocampal NMDA receptors: Protective role of Erdosteine

Isoniazid (INH) has neurotoxic effects such as seizure, poor concentration, subtle reduction in memory, anxiety, depression and psychosis. INH-induced toxic effects are thought to be through increased oxidative stress, and these effects have been shown to be prevented by antioxidant therapies in various organs. Increased oxidative stress may be playing a role in these neurotoxic effects. N-methyl D-aspartat receptors (NMDA) are a member of the ionotropic group of glutamate receptors. These receptors are involved in a wide variety of processes in the central nervous system including synaptogenesis, synaptic plasticity, memory and learning. Erdosteine is a potent antioxidant and mucolytic agent. We aimed to investigate adverse effects of INH on rat hippocampal NMDAR receptors, and to elucidate whether erdosteine prevents possible adverse effects of INH. In the present study, compared to control group, NMDAR2A (NR2A) receptors were significantly decreased and malondialdehyde (MDA), end product of lipid peroxidation, production was significantly increased in INH-treated group. On the other hand, administration of erdosteine to INH-treated group significantly increased NR2A receptors and decreased MDA production. In conclusion, decreasing NR2A receptors in hippocampus and increasing lipid peroxidation correlates with the degree of oxidative effects of INH and erdosteine protects above effect of INH on NR2A receptors and membrane damage due to lipid peroxidation by its antioxidant properties.     

Advantages of intramedullar fixation in treatment of congenital tibial pseudoarthrosis--a case report

This report describes a case of a 29-year old patient with congenital pseudoarthrosis of the distal tibia previously treated unsuccessfully by a conventional surgical method. Tibial congenital pseudoarthrosis is a rare disease characterized by segmental osseous weakness resulting in deformation of the bone and spontaneous fractures which progresses to a tibial nonunion. In our case we used intramedullary stabilization with bone grafting and six month after operation congenital pseudarthrosis of the tibia healed.     

Trace Elements in Obese Turkish Children

The quality of the diet of obese children is poor. Eating habits may alter micronutrient status in obese patients. In this study, we determined the serum levels of selenium, zinc, vanadium, molybdenum, iron, copper, beryllium, boron, chromium, manganese, cobalt, silver, barium, aluminum, nickel, cadmium, mercury, and lead in obese Turkish children. Thirty-four obese and 33 healthy control subjects were enrolled in the study. Serum vanadium and cobalt levels of obese children were significantly lower than those of the control group (0.244 ± 0.0179 vs. 0.261 ± 0.012 μg/l, p < 0.001, and 0.14 ± 0.13 vs. 0.24 ± 0.15 μg/l, p = 0.011, respectively). There was no significant difference between groups regarding the other serum trace element levels. In conclusion, there may be alterations in the serum levels of trace elements in obese children and these alterations may have a role in the pathogenesis of obesity.     

Electrostatic attraction by surface charge does not contribute to the catalytic efficiency of acetylcholinesterase.

Acetylcholinesterases (AChEs) are characterized by a high net negative charge and by an uneven surface charge distribution, giving rise to a negative electrostatic potential extending over most of the molecular surface. To evaluate the contribution of these electrostatic properties to the catalytic efficiency, 20 single- and multiple-site mutants of human AChE were generated by replacing up to seven acidic residues, vicinal to the rim of the active-center gorge (Glu84, Glu285, Glu292, Asp349, Glu358, Glu389 and Asp390), by neutral amino acids. Progressive simulated replacement of these charged residues results in a gradual decrease of the negative electrostatic potential which is essentially eliminated by neutralizing six or seven charges. In marked contrast to the shrinking of the electrostatic potential, the corresponding mutations had no significant effect on the apparent bimolecular rate constants of hydrolysis for charged and non-charged substrates, or on the Ki value for a charged active center inhibitor. Moreover, the kcat values for all 20 mutants are essentially identical to that of the wild type enzyme, and the apparent bimolecular rate constants show a moderate dependence on the ionic strength, which is invariant for all the enzymes examined. These findings suggest that the surface electrostatic properties of AChE do not contribute to the catalytic rate, that this rate is probably not diffusion-controlled and that long-range electrostatic interactions play no role in stabilization of the transition states of the catalytic process.     

Deletion of pancreatic β‐cell adenosine kinase improves glucose homeostasis in young mice and ameliorates streptozotocin‐induced hyperglycaemia

Severe reduction in the β‐cell number (collectively known as the β‐cell mass) contributes to the development of both type 1 and type 2 diabetes. Recent pharmacological studies have suggested that increased pancreatic β‐cell proliferation could be due to specific inhibition of adenosine kinase (ADK). However, genetic evidence for the function of pancreatic β‐cell ADK under physiological conditions or in a pathological context is still lacking. In this study, we crossed mice carrying LoxP‐flanked Adk gene with Ins2‐Cre mice to acquire pancreatic β ‐cell ADK deficiency (Ins2‐Cre^±Adk^fl/fl) mice. Our results revealed that Ins2‐Cre^+/‐Adk^fl/fl mice showed improved glucose metabolism and β‐cell mass in younger mice, but showed normal activity in adult mice. Moreover, Ins2‐Cre^±Adk^fl/fl mice were more resistant to streptozotocin (STZ) induced hyperglycaemia and pancreatic β‐cell damage in adult mice. In conclusion, we found that ADK negatively regulates β‐cell replication in young mice as well as under pathological conditions, such as STZ induced pancreatic β‐cell damage. Our study provided genetic evidence that specific inhibition of pancreatic β‐cell ADK has potential for anti‐diabetic therapy.     

20-Hydroxyecdysone mediated activation of larval haemolymph protein uptake by fat body cells of Corcyra cephalonica (Insecta)

Evidence is presented here to show that 20-hydroxyecdysone is essential for the activation of the larval fat body for differential uptake of larval haemolymph proteins (LHPs). By using radiolabelled LHPs it is shown that the fat body cells of Corcyra cephalonica selectively incorporate LHPs during late-larval and prepupal development. Fluorographic analysis of the labelled fat body proteins from prepupal stage separated on sodium dodecyl-sulphate polyacrylamide gels suggests that the LHPs are sequestered without any degradation. Although, during the last larval instar the uptake of all the three LHPs (LHP 1, LHP 2 and LHP 3) by the fat body cells is very low, 20-hydroxyecdysone treatment of early, mid or late-last instars causes a significant increase in uptake of all the three LHPs. However, the response to hormone treatment was more pronounced in late-last instar when compared to early and mid-last instar.