Modulation of smooth muscle phenotype in vitro by homologous cell substrate

We have developed a novel cell culture system that supports the shortening of smooth muscle cells. Primary rat airway smooth muscle cells were plated on an ethanol-fixed, confluent monolayer of homologous smooth muscle cells (homologous cell substrate, HCS). Cells grown on HCS exhibited morphological and functional characteristics consistent with a differentiated phenotype. Cells on HCS were spindle shaped with a well-defined long axis, whereas cells grown on glass were larger and irregularly shaped. Smooth muscle-specific alpha-actin immunostained diffusely in cells on HCS, whereas it appeared as stress fibers in cells on glass. Agonists recruited a greater fraction of HCS cells to contract, resulting in greater changes in cell area or length on average, but the maximal capacity of shortening of individual cells was similar between the groups. Unlike cells on glass, cells on HCS shortened to methacholine. HCS was reversible and persisted over several passages. Agonists stimulated intracellular Ca(2+) oscillations in cells on HCS, whereas they elicited biphasic peak and plateau transients in cells on glass. HCS modulates smooth muscle cell phenotype in vitro.

Role of postsynaptic density protein-95 in the maintenance of peripheral nerve injury-induced neuropathic pain in rats

Our previous work has demonstrated that postsynaptic density protein-95, a molecular scaffolding protein that binds and clusters N-methyl-D-aspartate receptors at neuronal synapses, plays an important role in the development of peripheral nerve injury-induced neuropathic pain. The current study further investigated the possible involvement of postsynaptic density protein-95 in the maintenance of neuropathic pain. Mechanical and thermal hyperalgesia were induced within 3 days and maintained for 15 days or longer after unilateral injury to the fifth lumbar spinal nerve. The rats injected intrathecally with postsynaptic density protein-95 antisense oligodeoxynucleotide every 24 h for 4 days from day 7 to day 10 post-surgery exhibited not only a marked decrease in spinal cord postsynaptic density protein-95 protein expression but also a significant reduction in mechanical and thermal hyperalgesia on day 11 post-surgery. The rats injected with sense oligodeoxynucleotide did not display these changes. However, in the rats without nerve injury, postsynaptic density protein-95 antisense oligodeoxynucleotide given intrathecally every 24 h for 4 days did not affect responses to mechanical and thermal stimulation. In addition, postsynaptic density protein-95 antisense oligodeoxynucleotide did not change locomotor activity of experimental animals. Our results indicate that the deficiency of postsynaptic density protein-95 protein in the spinal cord significantly attenuates nerve injury-induced mechanical and thermal hyperalgesia during both the development and maintenance of chronic neuropathic pain. These results suggest that postsynaptic density protein-95 might be involved in the central mechanisms of chronic neuropathic pain and provide a novel target for development of new pain therapies.

Effect of greenbugs (Homoptera: Aphididae) on yield loss of winter wheat

The effect of greenbug, Schizaphis graminum (Rondani), feeding on the yield of four winter wheat cultivars commonly grown in Oklahoma was studied. Cultivars tested were 'Karl', a recent derivative 'Karl-92', and '2163', all greenbug-susceptible cultivars; and 'TAM-110', a cultivar with resistance to biotype E greenbugs. The objectives were to determine the effect of different greenbug densities during fall and spring on yield of winter wheat, and to develop mathematical models to quantify the effect of greenbugs on yield loss. The intensity of greenbug infestations achieved in plots by artificial infestation varied among years and growing seasons within a year, but was generally sufficient to cause a reduction in yield. Among yield components, the number of heads per square meter and the number of seeds per head were frequently negatively correlated with the accumulated number of greenbug-days per tiller. Seed weight was rarely affected by greenbug infestation. A regression model estimated yield loss for greenbug-susceptible cultivars at 0.51 kg/ha loss of yield per greenbug-day in years with near normal precipitation, and a loss of 1.17 kg/ha under severe drought conditions. The susceptible winter wheat cultivars exhibited similar yield loss in relation to the intensity of greenbug infestation, as indicated by a common slope parameter in the regression model. Results suggest that the model is robust for predicting yield loss for susceptible cultivars.

Knockdown of PSD-95/SAP90 delays the development of neuropathic pain in rats

Our previous work has shown that PSD-95/SAP90 is required for NMDA receptor-mediated thermal hyperalgesia. To address the role of PSD-95/SAP90 in chronic pain, the present study investigated the effect of the deficiency of PSD-95/SAP90 on nerve injury-induced neuropathic pain. Following unilateral L5 spinal nerve injury, mechanical and thermal hyperalgesia developed within 3 days and persisted for 9 days or longer on the injured side. The intrathecal administration of antisense oligodeoxynucleotide specifically against PSD-95/SAP90, but not sense or missense oligodeoxynucleotide, dose-dependently delayed the onset of tactile allodynia and thermal hyperalgesia. These results suggest that PSD-95/SAP90 might be involved in the central mechanisms of the development of chronic neuropathic pain.

Selective binding of the cyano group in acrylonitrile adsorption on Si(100)-2 x 1

The covalent binding of acrylonitrile (CH(2)=CH-C triple bond N) and the formation of a C=C-C=N structure on Si(100) have been investigated using high-resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and density functional theory (DFT) calculations. For chemisorbed acrylonitrile, the absence of nu(C triple bond N) at 2245 cm(-1) and the appearance of nu(C=N) at 1669 cm(-1) demonstrate that the cyano group directly participates in the interaction with Si(100), which is further supported by XPS and UPS observations. Our experimental results and DFT calculations unambiguously demonstrate a [2 + 2] cycloaddition mechanism for acrylonitrile chemisorption on Si(100) through the binding of C triple bond N to Si dimers. The resulting chemisorbed monolayer with a C=C-C=N skeleton can serve as a precursor for further chemical syntheses of multilayer organic thin films in a vacuum and surface functionalization for in situ device fabrication.

Role of excitatory amino acid transporter 1 in neonatal rat neuronal damage induced by hypoxia-ischemia

The role of excitatory amino acid transporter 1 in neonatal rat neuronal damage was studied following hypoxia-ischemia. To induce hypoxia-ischemia injury, rats on postnatal day 7 were exposed to 8 % oxygen for 2 h following unilateral common carotid artery ligation. According to brain damage scoring based on Cresyl Violet staining, the neuronal damage time-dependently changed in the ischemic regions following hypoxia-ischemia. Immunohistochemical studies showed that excitatory amino acid transporter 1 expression was mainly observed in the cerebral cortex ipsilateral to common carotid artery ligation and markedly increased at 24 h and 48 h following hypoxia-ischemia. Combined with confocal laser scanning microscopic analysis, double staining showed that excitatory amino acid transporter 1 positive staining appeared in neurons as well as astrocytes after hypoxia-ischemia. Most excitatory amino acid transporter 1 positive staining cells exhibited regular morphological characteristics and only a few were double-stained by terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick-end labeling. Down-regulation of excitatory amino acid transporter 1 expression by intraventricular administration of specific antisense oligonucleotide exacerbated neuronal damage in hypoxia-ischemia brain. These results suggest that the increase of excitatory amino acid transporter 1 expression may be involved in a pathophysiological process of hypoxia-ischemia brain damage and may reflect a self-compensative mechanism for protecting neurons from further injury.

Pressure cycling technology: a novel approach to virus inactivation in plasma

BACKGROUND

Hydrostatic-pressure virus inactivation is a novel approach to the inactivation of pathogens in plasma and blood-derived components, that retains the therapeutic properties of these products.

STUDY DESIGN AND METHODS

A custom-built apparatus was used to pressurize human plasma samples spiked with lambda phage. Phage titer and plasma protein activities were monitored after pressure treatment.

RESULTS

Pressure-mediated inactivation of lambda phage was found to be an effective means for virus inactivation, particularly when performed at near-zero (0 degrees C) temperatures, rather than at temperatures above 20 degrees C and below -40 degrees C. The efficiency of inactivation was improved by an increase in applied pressure and repeated cycling from atmospheric to high pressure. In contrast, activities of plasma proteins alkaline phosphatase and total amylase did not vary with temperature and remained within 29 percent and 6 percent, respectively, of starting values after the same pressure treatments. By combining cycling, near-zero temperatures, and high pressure, phage titers in serum were reduced approximately 6 log after 10 to 20 minutes of treatment. Activities of plasma proteins IgG, IgM, and factor X were at 104 percent, 89 percent, and 80 percent, respectively, of starting values after 20 minutes of the same temperature and pressure treatment.

CONCLUSION

High-pressure procedures may be useful for the inactivation of viruses in blood and other protein-containing components.

A bioseparation apparatus with high-pressure fluid injection and fluid sampling

A novel apparatus in which fluids may be injected and sampled at high pressure is described. Bioseparation applications of the apparatus were demonstrated in three model systems: (1) lambdaDNA was eluted under pressure from an anion exchange column into a low-salt (0.25 M) buffer, thereby eliminating conventional time-consuming desalting procedures required for downstream analysis of the DNA; (2) RNA was separated under pressure from a RNA/DNA mixture, thereby enabling rapid differential preparation of nucleic acids; and (3) an antibody was purified from a protein mixture by affinity capture at one pressure and dissociation from the antigen binding partner at a second pressure, thereby enabling the immunoreactivities of both antibody and antigen to be preserved during the separation process.

Hypoxia-ischemia altered expression of glutamate transporter EAAT1 in neonatal rat brain

AIM

To observe altered expression of glutamate transporter EAAT1 after hypoxia-ischemia (H-I) in newborn rat brain.

METHODS

Expression levels of EAAT1 were detected with immunohistochemistry method.

RESULTS

EAAT1 was a little expressed in cerebral cortex at sham-operated group [(36 +/- 10) cells/slice]. Its expression in cerebral cortex increased at 24 h and 48 h following H-I [(314 +/- 162) cells/slice and (431 +/- 149) cells/slice, respectively], and recovered to control level at 72 h following H-I [(52 +/- 8) cells/slice]. The expression of EAAT1 in the ipsilateral cortex to common carotid artery (CCA) ligation was higher than that in the contralateral cortex.

CONCLUSION

After H-I, the expression of EAAT1 had a temporal change in cerebral cortex of newborn rat, and was mainly located in the ipsilateral cortex to CCA ligation.

A CCHC metal-binding domain in Nanos is essential for translational regulation

The Drosophila Nanos protein is a localized repressor of hunchback mRNA translation in the early embryo, and is required for the establishment of the anterior-posterior body axis. Analysis of nanos mutants reveals that a small, evolutionarily conserved, C-terminal region is essential for Nanos function in vivo, while no other single portion of the Nanos protein is absolutely required. Within the C-terminal region are two unusual Cys-Cys-His-Cys (CCHC) motifs that are potential zinc-binding sites. Using absorption spectroscopy and NMR we demonstrate that the CCHC motifs each bind one equivalent of zinc with high affinity. nanos mutations disrupting metal binding at either of these two sites in vitro abolish Nanos translational repression activity in vivo. We show that full-length and C-terminal Nanos proteins bind to RNA in vitro with high affinity, but with little sequence specificity. Mutations affecting the hunchback mRNA target sites for Nanos-dependent translational repression were found to disrupt translational repression in vivo, but had little effect on Nanos RNA binding in vitro. Thus, the Nanos zinc domain does not specifically recognize target hunchback RNA sequences, but might interact with RNA in the context of a larger ribonucleoprotein complex.

Radiation effects on late cytopathological parameters in the murine lens relative to particle fluence

Lenses of mice irradiated with 250 MeV protons, 670 MeV/amu 20Ne, 600 MeV/amu 56Fe, 600 MeV/amu 93Nb and 593 MeV/amu 139La ions were evaluated by analyzing cytopathological indicators which have been implicated in the cataractogenic process. The LETs ranged from 0.40 keV/micrometer to 953 keV/micrometer and fluences from 1.31 10(3)/mm2 to 4.99 x 10(7)/mm2. 60Co gamma-rays were used as the reference radiation. The doses ranged from 10 to 40 cGy. The lenses were assessed 64 weeks post irradiation in order to observe the late effects of LET and dose on the target cell population of the lens epithelium. Our study shows that growth dependent pathological changes occur at the cellular level as a function of dose and LET. The shapes of the RBE-LET and RBE-dose curves are consistent with previous work on eye and other biological systems done in both our laboratory and others. The RBEmax's were estimated, for the most radiation cataract related cytological changes, MN frequency and MR disorganization, by calculating the ratio of the initial slopes of dose effect curve for various heavy ions to that of 60Co gamma-ray. For each ion studied, the RBEmax derived from micronucleus (MN) frequency is similar to that derived from meridional row (MR) disorganization, suggesting that heavy ions are equally efficient at producing each type of damage. Furthermore, on a per particle basis (particle/cell nucleus), both MN frequency and MR disorganization are LET dependent indicating that these classic precataractogenic indicators are multi-gene effects. Poisson probability analysis of the particle number traversing cell nuclei (average area = 24 micrometers2) suggested that single nuclear traversals determine these changes. By virtue of their precataractogenic nature the data on these endpoints intimate that radiation cataract may also be the consequence of single hits. In any case, these observations are consistent with the current theory of the mechanism of radiation cataractogenesis, which proposes that genomic damage to the epithelial cells surviving the exposure is responsible for opacification.

[Analysis of the acetylcholine action on the electrical activities of pancreatic islet B-cells in mice]

Intracellular potential recording and extracellular microiontophoretic techniques were used to study the acetylcholine (ACh) action on the electrical activities of pancreatic islet B-cells in mice. The B cell membrane potential was decreased (5-10 mV) and the spikes were increased (11-17/30 s) by the ACh microinotophoresis. These effects were dependent on glucose and completely blocked by atropine. However, pirenzepine could attenuate the electrical activity by approximately 70%. The ACh-induced membrane depolarization was Ca(2+)-independent and blocked by TTX. But the effect of ACh on spikes was Ca(2+)-dependent and not blocked by verapamil. The results showed that ACh action in the enhancement of glucose-dependent electrical activities of B-cell were mediated by muscarinic receptor, mainly by subtype M1. Then TTX-sensitive Na channel and verapamil-insensitive Ca channel were activated by M1 receptors. Na+ influx resulted in membrane depolarization and Ca2+ influx enhanced spike discharges.

The influence of dose, dose-rate and particle fragmentation on cataract induction by energetic iron ions

Because activities in space necessarily involve chronic exposure to a heterogeneous charged particle radiation field it is important to assess the influence of dose-rate and the possible modulating role of heavy particle fragmentation on biological systems. Using the well-studied cataract model, mice were exposed to plateau 600 MeV/amu 56Fe ions either as acute or fractionated exposures at total doses of 5 - 504 cGy. Additional groups of mice received 20, 360 and 504 cGy behind 50 mm of polyethylene, which simulates body shielding. The reference radiation consisted of 60Co gamma radiation. The animals were examined by slit lamp biomicroscopy over their three year life spans. In accordance with our previous observations with heavy particles, the cataractogenic potential of the 600 MeV/amu 56Fe ions was greater than for low-LET radiation and increased with decreasing dose relative to gamma-rays. Fractionation of a given dose of 56Fe ions did not reduce the cataractogenicity of the radiation compared to the acute regimen. Fragmentation of the beam in the polyethylene did not alter the cataractotoxicity of the ions, either when administered singly or in fractions.

[Transportation trends after rat renal intracapsular injection of Salvia miltiorrhizae]

The concentration of Salvia miltiorrhizae (SM) was detected at different time after renal intracapsular injection in S.D rats. It showed that SM concentration was higher in kidney than in plasma (P < 0.05). SM concentration in kidney increased gradually, it reached the peak at 24 hour and still remained in higher level at 48 hour. The SM injected in renal capsule could be passively transported to renal tissue and maintained at a high level. This result demonstrated that renal intracapsular injection could be applied as an important therapeutical method for different renal disease.

Accelerated heavy ions and the lens. IX. Late effects of LET and dose on cellular parameters in the murine lens

Lenses of mice irradiated with 250 MeV protons, 670 MeV/amu 20Ne, 600 MeV/amu 56Fe, 350 MeV/amu 56Fe, 600 MeV/amu 93Nb or 593 MeV/amu 139La ions were evaluated by analysing cytopathological indicators which have been implicated in the cataractogenic process. The LETs ranged from 0.39 to 953 keV/microns and the fluences from 1.31 x 10(3)/mm2 to 5.12 x 10(7)/mm2. The lenses were assessed 64 weeks post-irradiation in order to observe the late effects of LET and dose on the target cell population of the lens' epithelium. Our studies showed that growth-dependent pathological changes occurred at the cellular level as a function of dose and LET. For a given particle dose, as the LET rose, the number of abnormal mitotic figures, micronuclei frequency, and the disorganization of meridional rows increased to a maximum and then reached a plateau or decreased. For particles of the same LET, the severity of meridional rows disorganization and micronuclei frequency increased with increasing dose. The numbers of cells surviving at late times post-irradiation were comparable with those of controls. In addition, the cellular density was similarly unaffected. These observations are consistent with the current theory of the mechanism of radiation cataractogenesis which posits that genomic damage to the epithelial cells surviving the exposure is responsible for opacification.

Crevice-forming mutants of bovine pancreatic trypsin inhibitor: stability changes and new hydrophobic surface

Four mutants of bovine pancreatic trypsin inhibitor (BPTI) with replacements in the rigid core result in the creation of deep crevices on the surface of the protein. Other than crevices at the site of the mutation, few other differences are observed in the crystal structures of wild-type BPTI and the mutants F22A, Y23A, N43G, and F45A. These mutants are highly destabilized relative to wild type (WT). The differences between WT and mutants in the free energy change associated with cooperative folding/unfolding, delta delta G0 (WT-->mut), have been measured by calorimetry, and they are in good agreement with delta delta G0(WT-->mut) values from hydrogen exchange rates. For F22A the change in free energy difference is about 1.7 kcal/mol at 25 degrees C; for the other three mutants it is in the range of 5-7 kcal/mol at 25 degrees C. The experimental delta delta G0(WT-->mut) values of F22A, Y23A, and F45A are reasonably well accounted for as the sum of two terms: the difference in transfer free energy change, and a contribution from exposure to solvent of new surface (Eriksson, A.E., et al., 1992, Science 255, 178-183), if the recently corrected transfer free energies and surface hydrophobicities (De Young, L. & Dill, K., 1990, J. Phys. Chem. 94, 801-809; Sharp, K.A., et al., 1991a, Science 252, 106-109) are used and only nonpolar surface is taken into account. In N43G, three protein-protein hydrogen bonds are replaced by protein-water hydrogen bonds.(ABSTRACT TRUNCATED AT 250 WORDS)

Crevice-forming mutants in the rigid core of bovine pancreatic trypsin inhibitor: crystal structures of F22A, Y23A, N43G, and F45A

Crystal structures of four mutants of bovine pancreatic trypsin inhibitor (F22A, Y23A, N43G, and F45A), engineered to alter their stability properties, have been determined. The mutated residues, which are highly conserved among Kunitz-type inhibitors, are located in the rigid core of the molecule. Replacement of the partially buried bulky residues of the wild-type protein with smaller residues resulted in crevices open to the exterior of the molecule. The overall three-dimensional structure of these mutants is very similar to that of the wild-type protein and only small rearrangements are observed among the atoms lining the crevices.

Comparison of hydrogen exchange rates for bovine pancreatic trypsin inhibitor in crystals and in solution

Hydrogen exchange rate constants for the 17 slowest exchanging amide NH groups in bovine pancreatic trypsin inhibitor (BPTI) were measured in solution and in form II and form III crystals. All 17 amide hydrogens are buried and intramolecularly hydrogen bonded in the crystal structure, except Lys 41 which is buried and hydrogen bonded to a buried water. Large-scale crystallization procedures were developed for these experiments, and rate constants for both crystal and solution exchange were measured by 1H NMR spectroscopy of exchange-quenched samples in solution. Two conditions of pH and temperature, pH 9.8 and 35 degrees C, and pH 9.4 and 25 degrees C, bring two groups of hydrogens into the experimental time window (minutes to weeks). One consists of the 10 slowest exchanging hydrogens, all of which are associated with the central beta-sheet of BPTI. The second group consists of seven more rapidly exchanging hydrogens, which are distributed throughout the molecule, primarily in a loop or turn. In both groups, most hydrogens exchange more slowly in crystals, but there is considerable variation in the degree to which the exchange is depressed in crystals. Many differences observed for the more rapidly exchanging hydrogens can be attributed to local surface effects arising from intermolecular contacts in the crystal lattice. Within the slower group, however, a very large effect on exchange of Ile 18 and Tyr 35 appears to be selectively transmitted through the matrix of the molecule.(ABSTRACT TRUNCATED AT 250 WORDS)