Effect of environmental temperature on biosynthesis of liver phosphatidyl-choline in the trout (Salmo gairdnerii)

1. 1.The changes in fatty acid composition of trout liver phosphatidyl-choline, when the environmental temperature was increased, resulted in modifications in the amounts of the different molecular species.

2. 2.In vivo, incorporation of ³²P occurred more rapidly in the molecular species with high degree of unsaturation.Temperature acclimation did not modify the relative proportions of label shown in the five subfractions.

3. 3.In vitro incorporation of ¹⁴C-methyl-choline also occurred more rapidly in the most unsaturated molecular species. However, when the incubation temperature was raised, the proportion of label decreased in the unsaturated fractions.

Chromium-resistant bacteria and cyanobacteria: impact on Cr(VI) reduction potential and plant growth

Two chromium-resistant bacterial strains, Bacillus cereus S-6 and Ochrobactrum intermedium CrT-1, and two cyanobacterial strains, Oscillatoria sp. and Synechocystis sp., were used in this study. At initial chromate concentrations of 300 and 600 microg K2CrO4 mL(-1), and an inoculum size of 9.6 x 10(7) cells mL(-1), B. cereus S-6 completely reduced Cr(VI), while O. intermedium CrT-1 reduced Cr(VI) by 98% and 70%, respectively after 96 h. At 100 microg K2CrO4 mL(-1), Synechocystis sp. MK(S) and Oscillatoria sp. BJ2 reduced 62.1% and 39.9% of Cr(VI), respectively, at 30 degrees C and pH 8. Application of hexavalent chromate salts adversely affected wheat seedling growth and anatomical characters. However, bacterial inoculation alleviated the toxic effects, as reflected by significant improvements in growth as well as anatomical parameters. Cyanobacterial strains also led to some enhancement of various growth parameters in wheat seedlings.     

Mice carrying a R142C Notch 3 knock-in mutation do not develop a CADASIL-like phenotype

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy, MIM 125310) is a genetic vascular dementia disease that is linked to missense mutations, small in-frame deletions, and splice site mutations in the human Notch 3 gene. Here we describe the generation of a mouse knockin model for one of the most prevalent CADASIL mutations, an arginine to cysteine transition at position 141, R141C, which corresponds to mutation R142C in mouse NOTCH 3. CADASIL(R142C) mice show no apparent CADASIL-like phenotype after histological and MRI analysis. The NOTCH 3 (R142C) receptor is processed normally and does not appear to accumulate the ectodomain, which has been observed in CADASIL patients. We discuss possible reasons for the different outcomes of the same germline CADASIL mutation in mice and humans.     

Numerical study of the impact of non-Newtonian blood behavior on flow over a two-dimensional backward facing step

Endothelial cell (EC) responsiveness to shear stress is essential for vasoregulation and plays a role in atherogenesis. Although blood is a non-Newtonian fluid, EC flow studies in vitro are typically performed using Newtonian fluids. The goal of the present study was to determine the impact of non-Newtonian behavior on the flow field within a model flow chamber capable of producing flow disturbance and whose dimensions permit Reynolds and Womersley numbers comparable to those present in vivo. We performed two-dimensional computational fluid dynamic simulations of steady and pulsatile laminar flow of Newtonian and non-Newtonian fluids over a backward facing step. In the non-Newtonian simulations, the fluid was modeled as a shear-thinning Carreau fluid. Steady flow results demonstrate that for Re in the range 50-400, the flow recirculation zone downstream of the step is 22-63% larger for the Newtonian fluid than for the non-Newtonian fluid, while spatial gradients of shear stress are larger for the non-Newtonian fluid. In pulsatile flow, the temporal gradients of shear stress within the flow recirculation zone are significantly larger for the Newtonian fluid than for the non-Newtonian fluid. These findings raise the possibility that in regions of flow disturbance, EC mechanotransduction pathways stimulated by Newtonian and non-Newtonian fluids may be different.     

Antioxidant, radical-scavenging, anti-inflammatory, cytotoxic and antibacterial activities of methanolic extracts of some Hedyotis species

The antioxidant, radical-scavenging, anti-inflammatory, cytotoxic and antibacterial activities of methanolic extracts of seven Hedyotisspecies were investigated. The antioxidant activity was evaluated by the ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods while the radical scavenging activity was measured by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The anti-inflammatory activity related to NO inhibition of the plant extracts was measured by the Griess assay while cytotoxicity were measured by the MTT assay against CEM-SS cell line. The antibacterial bioassay (against 4 bacteria, i.e. Bacillus subtilis B28 (mutant), Bacillus subtilis B29 (wild-type), Pseudomonas aeruginosa UI 60690 and methicillin resistant Staphylococcus aureus, (MRSA) was also carried out using the disc-diffusion method. All tested extracts exhibited very strong antioxidant properties when compared to Vitamin E (alpha-tocopherol) with percent inhibition of 89-98% in the FTC and 60-95% in the TBA assays. In the DPPH method, H. herbacea exhibited the strongest radical scavenging activity with an IC50 value of 32 microg/ml. The results from the Griess assay showed that the tested extracts are weak inhibitors of NO synthase. However, all tested extracts exhibited moderate cytotoxic properties against CEM-SS cell line giving CD50 values in the range of 21-41 microg/ml. In the antibacterial bioassay, the stems and the roots of H. capitellata showed moderate activity against the 4 tested bacteria while the leaves showed moderate activity towards B. subtilis B28, MRSA and P. aeruginosa only. The roots of H. dichotoma showed strong antibacterial activity against all 4 bacteria. All other extracts did not exhibit any antibacterial activity.     

Breast myeloma: a report of 3 cases with fine needle aspiration cytologic findings

BACKGROUND: Multiple myeloma of the breast is very rare, and the fine needle aspiration (FNA) findings have not been reported before. CASES: Two cases of multiple myeloma presented with bilateral breast nodules during treatment with chemotherapy. One case of multiple myeloma presented initially with a left breast mass. FNA smears of all 3 cases revealed numerous plasma cells, plasmablasts and multinucleated giant plasma cells. The smears were diagnosed as plasma cell tumors. Serum immunoelectrophoresis revealed IgG myeloma in 2 cases and IgA myeloma in 1. Marrow aspirates revealed > 30% plasma cells. Two patients died, and 1 was alive at this writing. CONCLUSION: The aspiration cytology findings of myeloma can be confuse, with primary and secondary tumors of the breast. The previous clinical history and ancillary studies, such as bone marrow study and serum immunoelectrophoresis, are essential to the correct diagnosis.     

Withanolides, a new class of natural cholinesterase inhibitors with calcium antagonistic properties

The withanolides 1-3 and 4-5 isolated from Ajuga bracteosa and Withania somnifera, respectively, inhibited acetylcholinesterase (AChE, EC 3.1.1.7) and butyrylcholinesterase (BChE, EC 3.1.1.8) enzymes in a concentration-dependent fashion with IC50 values ranging between 20.5 and 49,2 microm and 29.0 and 85.2 microm for AChE and BChE, respectively. Lineweaver-Burk as well as Dixon plots and their secondary replots indicated that compounds 1, 3, and 5 are the linear mixed-type inhibitors of AChE, while 2 and 4 are non-competitive inhibitors of AChE with K(i) values ranging between 20.0 and 45.0 microm. All compounds were found to be non-competitive inhibitors of BChE with K(i) values ranging between 27.7 and 90.6 microm. Molecular docking study revealed that all the ligands are completely buried inside the aromatic gorge of AChE, while compounds 1, 3, and 5 extend up to the catalytic triad. A comparison of the docking results showed that all ligands generally adopt the same binding mode and lie parallel to the surface of the gorge. The superposition of the docked structures demonstrated that the non-flexible skeleton of the ligands always penetrates the aromatic gorge through the six-membered ring A, allowing their simultaneous interaction with more than one subsite of the active center. The affinity of ligands with AChE was found to be the cumulative effects of number of hydrophobic contacts and hydrogen bonding. Furthermore, all compounds also displayed dose-dependent (0.005-1.0 mg/mL) spasmolytic and Ca2+ antagonistic potentials in isolated rabbit jejunum preparations, compound 4 being the most active with an ED50 value of 0.09 +/- 0.001 mg/mL and 0.22 +/- 0.01 microg/mL on spontaneous and K+ -induced contractions, respectively. The cholinesterase inhibitory potential along with calcium antagonistic ability and safe profile in human neutrophil viability assay could make compounds 1-5 possible drug candidates for further study to treat Alzheimer's disease and associated problems.     

Tyrphostins are inhibitors of guanylyl and adenylyl cyclases

Guanylyl cyclase C (GC-C), the receptor for guanylin, uroguanylin, and the heat-stable enterotoxin, regulates fluid balance in the intestine and extraintestinal tissues. The receptor has an extracellular domain, a single transmembrane spanning domain, and an intracellular domain that harbors a region homologous to protein kinases, followed by the C-terminal guanylyl cyclase domain. Adenine nucleotides can regulate the guanylyl cyclase activity of GC-C by binding to the intracellular kinase homology domain (KHD). In this study, we have tested the effect of several protein kinase inhibitors on GC-C activity and find that the tyrphostins, known to be tyrosine kinase inhibitors, could inhibit GC-C activity in vitro. Tyrphostin A25 (AG82) was the most potent inhibitor with an IC(50) of approximately 15 microM. The mechanism of inhibition was found to be noncompetitive with respect to both the substrate MnGTP and the metal cofactor. Interestingly, the activity of the catalytic domain of GC-C (lacking the KHD) expressed in insect cells was also inhibited by tyrphostin A25 with an IC(50) of approximately 5 microM. As with the full-length receptor, inhibition was found to be noncompetitive with respect to MnGTP. Inhibition was reversible, ruling out a covalent modification of the receptor. Structurally similar proteins such as the soluble guanylyl cyclase and the adenylyl cyclases were also inhibited by tyrphostin A25. Evaluation of a number of tyrphostins allowed us to identify the requirement of two vicinal hydroxyl groups in the tyrphostin for effective inhibition of cyclase activity. Therefore, our studies are the first to report that nucleotide cyclases are inhibited by tyrphostins and suggest that novel inhibitors based on the tyrphostin scaffold can be developed, which could aid in a greater understanding of nucleotide cyclase structure and function.     

Design and chemical synthesis of a magnetic resonance contrast agent with enhanced in vitro binding, high blood-brain barrier permeability, and in vivo targeting to Alzheimer's disease amyloid plaques

Molecular imaging is an important new direction in medical diagnosis; however, its success is dependent upon molecular probes that demonstrate selective tissue targeting. We report the design and chemical synthesis of a derivative of human amyloid-beta (Abeta) peptide that is capable of selectively targeting individual amyloid plaques in the brain of Alzheimer's disease transgenic mice after being intravenously injected. This derivative is based on the sequence of the first 30 amino acid residues of Abeta with asparagyl/glutamyl-4-aminobutane residues (N-4ab/Q-4ab) substituted at unique Asp and Glu positions and with Gd-DTPA-aminohexanoic acid covalently attached at the N-terminal Asp. The Gd[N-4ab/Q-4ab]Abeta30 peptide was homogeneous as shown by high-resolution analytical techniques with a mass of +/-4385 Da determined by electrospray ionization mass spectrometry. This diamine- and gadolinium-substituted derivative of Abeta is shown to have enhanced in vitro binding to Alzheimer's disease (AD) amyloid plaques and increased in vivo permeability at the blood-brain barrier because of the unique Asp/Glu substitutions. In addition, specific in vivo targeting to AD amyloid plaques is demonstrated throughout the brain of an APP, PS1 transgenic mouse after intravenous injection. Because of the magnetic resonance (MR) imaging contrast enhancement provided by gadolinium, this derivative should enable the in vivo MR imaging of individual amyloid plaques in the brains of AD animals or patients to allow for early diagnosis and also provide a direct measure of the efficacy of anti-amyloid therapies currently being developed.