Interleukin-1-β and Tumor Necrosis Factor-α Increase Peripheral-Type Benzodiazepine Binding Sites in Cultured Polygonal Astrocytes

Peripheral-type benzodiazepine binding sites (PTBBS) are markedly increased in the injured CNS. Astrocytes appear to be the primary cell type which express increased PTBBS. Because certain cytokines within the injured CNS are potent mitogens for astrocytes, we examined the effects of two such cytokines, interleukin (IL)-1 beta and tumor necrosis factor (TNF), on PTBBS in cultured astrocytes using [3H]Ro 5-4864 as the specific ligand. Purified cultures of either polygonal or process-bearing astrocytes were prepared from neonatal rat cerebral hemispheres. At a concentration of 1.8 nM, specific binding of the radioactive ligand to polygonal astrocytes reached equilibrium within 60 min and was half-maximal by 5-10 min. By contrast, specific binding to process-bearing astrocytes barely exceeded background levels. IL-1 and TNF increased PTBBS within polygonal astrocytes in both dose- and time-dependent manners. At 10-50 ng/ml, IL-1 beta and TNF-alpha elevated [3H]Ro 5-4864 binding in polygonal astrocyte cultures 65 and 87%, respectively, above the level in control cultures. However, no changes in PTBBS were seen within polygonal astrocytes after IL-2 treatment. Scatchard analysis of saturation binding experiments suggested that the increase in PTBBS promoted by TNF was due to an increased number of binding sites present in polygonal astrocytes and not due to an increase in receptor affinity. Binding data suggested that PTBBS within cultures of process-bearing astrocytes were virtually absent irrespective of the treatment. These in vitro data suggest that certain cytokines found in the injured brain may be involved in up-regulating PTBBS within a particular subtype of astrocyte.     

Improving the clinical efficiency of T2 mapping of ligament integrity

Current MR methods use T₂^? relaxation time as a surrogate measure of ligament strength. Currently, a multi-echo voxel-wise least squares fit is the gold standard to create T₂^? maps; however, the post-processing is time-intensive and serves as a stopgap for clinical use. The study objective was to determine if an alternative method could improve post-processing time without sacrificing fidelity of T₂^? values for eventual translational use in the clinic. Using a 6 echo FLASH sequence, three different methods were used to determine intact posterior cruciate ligament (PCL) median T₂^? Two of these methods utilized a voxel-wise method to establish T₂^? maps: (1) a current “gold standard” method using a voxel-wise 6 echo least-squares fit (6LS) and (2) a voxel-wise 2 echo point T₂^? determination (2MM). The third method used median ligament signal intensity and a single nonlinear least-squares fit (6LS_ROI) instead of a voxel-wise basis. The resulting median T₂^? values of the PCL and computational time were compared. The median T₂^? values were 42% higher using the 2MM compared to the 6LS method (p<0.0001). However, a strong correlation was found for the median T₂^? values between the 2MM and 6LS methods (R²=0.80). The median T₂^? values were not significantly different between the 6LS and 6LS_ROI methods (p=0.519). Using the 2MM (which provides a regional map) and the 6LS_ROI (which efficiently provides the median T₂^? value) methods in tandem would take only minutes of post-processing computational time compared to the 6LS method (~540 min), and hence would facilitate clinical application of T₂^? maps to predict ligament structural properties as a patient outcome measure.     

Synthesis and Analysis of Nucleosides Bearing Pyrrolepolyamide Binding to DNA

Abstract

An efficient synthesis of adenosine bearing pyrrolepolyamide 1 was achieved by coupling of 3 with 2. The CD spectra obtained at several [ligand ]/[duplex] ratios allowed verification of the formation complex of the DNA duplex [d(CGCAAATTGGC)/d(GCCAATTTGCG)] with 1.     

Localization of vanadium-containing particles in the lungs of uranium/vanadium miners

Several geological formations of the Utah-Colorado mining region mined for uranium ore during and after World War II had been mined earlier for vanadium. Therefore, most miners and millers from that region were exposed to those metals’ ores or tailings at one time or another. Preliminary investigation to determine uranium and vanadium retained in the lungs of a former uranium miner and miller from this region, who died of lung cancer (mesothelioma), showed a high nonuniform distribution of vanadium. This observation led to the hypothesis that the vanadium content in the lungs could be associated with inhaled particles. Further examination of spectra of characteristic X-rays obtained by scanning particle-induced X-ray emission (microPIXE) of an autopsy sample of this lung indicated that vanadium was indeed present in localized sites within the 20-μm spatial resolution of the proton beam. This work points out that the microPIXE-RBS (Rutherford backscattering) test for vanadium can be used for site localization of inhaled particles retained in the lungs. Further studies are in progress to: (i) locate uranium-bearing particles in lung tissues of former uranium miners and millers; and (ii) evaluate the local doses of alpha radiation received from these particles.     

Enzymatic Protein Carboxyl Methylation in Rat Posterior Pituitary: Neurophysins in Rapid-Turnover Pool Determine Methyl Accepting Capacity

In vitro stimulation of intact rat posterior pituitary by either veratridine or K+ depolarization results in the concomitant release of neurophysins and in a decrease (70-80%) in their carboxyl methylation as measured either with L-[methyl-3H]methionine in the intact lobes after stimulation or in their homogenates with [methyl-3H]S-adenosyl-L-methionine and purified protein carboxyl methyltransferase. A similar reduction in neurophysin methylation (60%) was observed when the arrival of newly synthesized neurophysins at the posterior pituitary was blocked by colchicine. Experimental data indicate that the reduction in neurophysin content of the lobes after 12 h of colchicine treatment (less than 7%) or after in vitro stimulation (about 10%) cannot account for the marked reduction in neurophysin methylation. The results suggest that the granule pool characterized by rapid turnover of neurophysins probably represents the major source of methyl acceptor proteins in the lobe. In spite of the marked reduction in neurophysin methyl accepting capacity observed after stimulation, there was no parallel increase in methyl accepting capacity of the released neurophysins. We propose that a neurophysin subfraction that might be associated with the membrane of releasable granules participates in the methylation reaction in situ.     

Biofilm reactors in anaerobic wastewater treatment

Attached biofilm reactors provide the means for implementing energy-efficient anaerobic wastewater treatment at full scale. Progress has been made in the development of fixed, expanded and fluidized bed anaerobic processes by addressing fundamental reactor design issues. Several new biofilm reactor concepts have evolved from recent studies.     

Fixed bed porous glass sphere (porosphere) bioreactors for animal cells

Process intensity of fixed bed glass sphere culture systems is increased considerably by replacing solid glass spheres with open pore glass spheres. This technique demonstrates the possibility of having a system capable of both volumetric and cell density scale up and being suitable for substrate attached and suspension cells. The yields achieved for a number of attached cell lines (approximately 10⁷/ml) demonstrate an increase approaching one order of magnitude over solid glass spheres (approximately 10⁶/ml). Also suspension cells were successfully entrapped in the open pore structure with similar yields.     

A periodicity result for a nonlinear functional integral equation

In this paper, we study the effect of introducing a delay in a model of cell proliferation considered originally by O. Arino and M. Kimmel (J. Math. Biol. 27, 341–354 (1989)). We prove that slow oscillations take place and periodic oscillations appear for appropriate values of a parameter.     

The membrane dialysis bioreactor with integrated radial-flow fixed bed —a new approach for continuous cultivation of animal cells

A hybridoma cell was cultivated continuously in a membrane dialysis bioreactor with an integrated radial-flow fixed bed consisting of porous Siran^® carriers over a period of 6 weeks. Antibodies accumulated to an average of 100 mg l^?1, approx. 10 times more than in fixed bed cultures without dialysis membrane. Serum costs could be reduced about 85% due to an appropriate feeding strategy. Siran^® carriers with 3–5 mm diameter showed an advantage compared to those with 1–2 mm diameter. For the 3–5 mm carrier the specific glucose uptake rate and the MAb production rate were constant, if the velocity was between 0.09 mm s^?1 and 0.75 mm s^?1. At higher velocities cells are washed out of the bed. Furthermore antibody consistency and cell stability were verified in long-term cultivations over a period of 96 days. From an estimation of the antibody concentration reachable with the reactor concept under optimal conditions a concentration 45 times higher compared to axial-flow fixed bed reactors and 11 times higher compared to stirred tank reactors can be expected.