Influence of aeration implements, phosphorus fertilizers, and soil taxa on phosphorus losses from grasslands.

Attenuation of rainfall within the solum may help to move contaminants and nutrients into the soil to be better sequestered or utilized by crops. Surface application of phosphorus (P) amendments to grasslands may lead to elevated concentrations of P in surface runoff and eutrophication of surface waters. Aeration of grasslands has been proposed as a treatment to reduce losses of applied P. Here, results from two small-plot aeration studies and two field-scale, paired-watershed studies are supplemented with previously unpublished soil P data and synthesized. The overall objective of these studies was to determine the impact of aeration on soil P, runoff volume, and runoff P losses from mixed tall fescue [Lolium arundinaceum (Schreb.) Darbysh.]-bermudagrass (Cynodon dactylon L.) grasslands fertilized with P. Small-scale rainfall simulations were conducted on two soil taxa using three types of aeration implements: spikes, disks, and cores. The-field scale study was conducted on four soil taxa with slit and knife aeration. Small-plot studies showed that core aeration reduced loads of total P and dissolved reactive P (DRP) in runoff from plots fertilized with broiler litter and that aeration was effective in reducing P export when it increased soil P in the upper 5 cm. In the field-scale study, slit aeration reduced DRP losses by 35% in fields with well-drained soils but not in poorly drained soils. Flow-weighted concentrations of DRP in aerated fields were related to water-soluble P applied in amendments and soil test P in the upper 5 cm. These studies show that the overall effectiveness of mechanical soil aeration on runoff volume and P losses is controlled by the interaction of soil characteristics such as internal drainage and compaction, soil P, type of surface-applied manure, and type of aeration implement.

Seminal plasma HIV levels in men with asymptomatic sexually transmitted infections.

The effect of asymptomatic sexually transmitted urethral infections on human immunodeficiency virus (HIV) RNA viral load in semen is poorly defined. We studied five such patients. Those on antiretrovirals (n = 2) had lower seminal plasma viral loads (SPVL) (2.11 and 1.98 log(10) copies/mL) than those not on antiretrovirals (n = 3) (2.27-3.78 log(10) copies/mL). One patient who was not taking antiretrovirals had a 94% decline in SPVL after treatment of asymptomatic Chlamydia trachomatis urethritis, suggesting that asymptomatic infection may be a co-factor for HIV transmission.

Interstellar cloud material: contribution to planetary atmospheres.

A statistical analysis of the properties of dense interstellar clouds indicates that the solar system has encountered at least a dozen clouds of sufficient density to cause planets to accumulate nonnegligible amounts of some isotopes. The effect is most pronounced for neon. This mechanism could be responsible for much of the neon in Earth's atmosphere. For Mars, the predicted amount of neon added by cloud encounters greatly exceeds the present abundance.

Therapeutic antibodies elicited by immunization against TNF-alpha.

Tumor necrosis factor-alpha (TNF-alpha) is critically involved in the pathogenesis of several chronic inflammatory diseases. Monoclonal antibodies against TNF-alpha are currently used for the treatment of rheumatoid arthritis and Crohn's disease. This report describes a simple and effective method for active immunization against self TNF-alpha. This vaccination approach leads to a T-cell-dependent polyclonal and sustainable anti-TNF-alpha autoantibody response that declines upon discontinuation of booster injections. The autoantibodies are elicited by injecting modified recombinant TNF-alpha molecules containing foreign immunodominant T-helper epitopes. In mice immunized with such molecules, the symptoms of experimental cachexia and type II collagen-induced arthritis are ameliorated. These results suggest that vaccination against TNF-alpha may be a useful approach for the treatment of rheumatoid arthritis and other chronic inflammatory diseases.

Recombinant human interleukin-1 stimulates human articular cartilage to undergo resorption and human chondrocytes to produce both tissue- and urokinase-type plasminogen activator.

Cytokines capable of stimulating cartilage resorption have frequently been identified as 'interleukin-1 (IL-1)-like' peptides. In this study for the first time we have employed homogeneous recombinant IL-1 alpha and IL-1 beta in an all-human culture system to define the effects of IL-1 on articular cartilage and chondrocytes in culture. Recombinant IL-1 (10-100 U/ml) could stimulate cartilage resorption, although the maximum degree of tissue breakdown rarely reached the levels obtained when cartilage was treated with crude mononuclear-cell conditioned medium or all-trans retinoic acid (1 microM) over a similar time course. Levels of plasminogen activator (PA) activity, a neutral proteinase which may contribute to cartilage destruction in arthritis, increased markedly in the cartilage/chondrocyte culture supernatants and in the chondrocyte cell layers in response to the stimulation of cultures with recombinant IL-1 (1-100 U/ml). Elevated levels of PA activity were detectable after 4-8 h stimulation of the chondrocytes with IL-1 while characterization of the PA activities indicated that both types of PA activity were expressed, viz. urokinase-type PA (u-PA) and tissue-type PA (t-PA). Both IL-1 alpha and IL-1 beta could elicit these responses and their effects were comparable for a given dose. These studies show definitively that pure IL-1, free from contaminating cytokines, is capable of inducing human cartilage resorption and stimulating the expression of two types of PA activity by chondrocytes. In contrast to IL-1, retinoic acid increased the detectable levels of only u-PA in the chondrocyte cell layers. Chondrocyte u-PA may have an important role in cartilage degradative processes since it is one of the few neutral proteinases now known to be increased in activity in retinoid-stimulated cartilage.

The importance of disc hemorrhage in the prognosis of chronic open angle glaucoma.

The progression of field damage of 48 eyes with chronic simple glaucoma and a splinter hemorrhage on the disc was compared with that of 48 chronic simple glaucoma eyes without hemorrhage. The incidence of visual field progression was substantially higher among those with a hemorrhage. Similar visual field progression was substantially higher in 29 eyes with elevated introcular pressure and a disc hemorrhage when compared with 29 ocular hypertensive patients with no hemorrhage. The prognostic importance of a disc hemorrhage is discussed.

Modulation of proinflammatory cytokine release in rheumatoid synovial membrane cell cultures. Comparison of monoclonal anti TNF-alpha antibody with the interleukin-1 receptor antagonist.

While there is an extensive literature on cytokine regulation in vivo using human cell lines or peripheral blood monocytes, very little is known about cytokine regulation within the multicellular environment of inflammatory sites in vivo. We have previously shown that in rheumatoid synovial membrane cultures, a complex, but pathophysiologically relevant mixture of cells, the addition of a neutralizing anti TNF-alpha antibody inhibits the production of IL-1 and GM-CSF, indicating the presence of a cytokine 'cascade' in this inflammatory tissue. In this paper we demonstrate that the interactivities between cytokines in rheumatoid arthritis also extends to other cytokines, such as IL-6 and IL-8, and that within the IL-1 family it is IL-1 beta in particular which is downregulated by neutralizing TNF-alpha activity. The cytokine interactions are unidirectional, in that neutralization of TNF-alpha reduced IL-1 beta, IL-6 and IL-8 production, whereas treatment of the rheumatoid synovial membrane cells with a neutralizing concentration of the IL-1 receptor antagonist (IL-1ra) reduced IL-6 and IL-8 production but not TNF-alpha production. These results suggest a rationale for the profound anti-inflammatory effects and consequent clinical benefit noted in RA patients treated recently in clinical trials with a chimeric anti-TNF-alpha antibody in vivo.

p55 and p75 tumor necrosis factor receptors are expressed and mediate common functions in synovial fibroblasts and other fibroblasts.

There is increasing evidence that TNF-alpha is a cytokine of major importance in the pathogenesis of rheumatoid arthritis. Since TNF-alpha mediates its effects via high affinity receptors, we were interested in investigating their expression and function in cells from rheumatoid tissue. Synovial fibroblasts derived from rheumatoid synovial tissue are stimulated by TNF-alpha to proliferate and release cytokines, prostaglandins, proteases and protease inhibitors. We have evaluated through which receptor stimulation of DNA synthesis and the release of the proinflammatory agents, IL-6, IL-8 and PGE2 are induced. It was found that rheumatoid synovial fibroblasts express both the p55 and p75 TNF receptor, in a ratio of 4:1. TNF-alpha-stimulated synovial fibroblast DNA synthesis and the release of IL-6, IL-8 and PGE2 was inhibited by antagonist monoclonal antibodies against either the p55 or the p75 TNF receptor, although the blockade of the p55 TNF receptor had a more potent effect than inhibition of the p75 TNF receptor alone. Similarly, specific monoclonal antibodies, agonistic for either the p55 or p75 TNF receptor stimulated synovial fibroblast DNA synthesis, as well as IL-6, IL-8 and PGE2 release. Both p55 and p75 TNF receptors on dermal and gingival fibroblasts were also involved in TNF-alpha-mediated DNA synthesis and IL-6, IL-8 and PGE2 release, although differences in the levels of DNA synthesis and release of inflammatory cytokines and PGE2 were observed between the three fibroblast types.

Combination therapy with DMARDs and biological agents in collagen-induced arthritis.

There is increasing interest in the use of combination therapy for rheumatoid arthritis and in the possibility of combining the conventional drug approach with newer biological therapies. Animal models of arthritis provide important tools for evaluating novel forms of therapy and for eludicating mechanisms of drug action. In this paper, we review the results of our own research into combination therapy in collagen-induced arthritis using biological therapies such as anti-tumor necrosis factor alpha, anti-CD4, and anti-interleukin 12 monoclonal antibodies, and small molecular weight compounds such as cyclosporin and the phosphodiesterase IV (PDE IV) inhibitor rolipram.

Factors influencing the penetration of wires into the neural canal during segmental wiring.

We evaluated the influence of the penetration of wires into the neural canal during segmental wiring in a three-part study. First we examined the anatomy of the thoracic spine, specifically the laminar and interlaminar dimensions, as well as the epidural space. In the second part, we evaluated the depth of penetration of wires into the spinal canal at the time of their passage during spinal segmental instrumentation, using direct laboratory measurements for three configurations of the wire: first with a straight wire, and then with two wires of varying curvature. The measurements were repeated after removal of a portion of the lamina. In the third and final part of the study, we assessed the relationship between the observed penetration of the wires and the depth of penetration as calculated using mathematical models for the three wire configurations. When a wire with the largest possible diameter of curvature was passed under the lamina, there was significantly less penetration using the curved-wire configuration. This was seen in calculated models, as well as in normal specimens of the thoracic spine that were obtained from cadavera. Little epidural space was found to be available for passage of the wire. In most instances, passage of the wire must result in contact with and displacement of the dural sac and its contents. To minimize the depth of penetration at any given spinal level, it is recommended that the wire be curved to the maximum degree that will allow it to pass under the lamina.(ABSTRACT TRUNCATED AT 250 WORDS)

On the antigenic relationship between the alpha A and alpha B subunits of alpha-crystallin in bovine lens.

The immunochemical reactivities of the alpha A and alpha B subunits from bovine alpha-crystallin have been compared using 5 monoclonal antibodies and 2 polyvalent antisera. Each subunit bound the same maximum amount of antibody, regardless of its source, and each subunit was able to completely displace alpha-crystallin from its antibodies. One monoclonal antibody (463-12.2) and mouse anti-alpha B polyclonal antiserum bound equally well to the two subunits; with the other monoclonal antibodies and an anti alpha-crystallin antiserum, the affinities for the alpha A chains were about 10(3) fold higher than those for the alpha beta chains. These observations indicate that the alpha A and alpha B subunits of bovine alpha-crystallin share several similar, but not necessarily identical, cross-reacting antigenic determinants. The reasons for the differences between these observations and those of other investigators are discussed.

Hearing loss in experimental cytomegalovirus infection of the guinea pig inner ear: prevention by systemic immunity.

Guinea pig cytomegalovirus (GPCMV) has been used to establish a reproducible model of viral labyrinthitis and hearing loss. Cochlear function was assessed by electrophysiological recordings of cochlear microphonic (CM) and eighth nerve N1 compound action potential (AP) thresholds prior to and up to eight days following inoculation of the scala tympani. Inner ear inoculation of seronegative subjects with live GPCMV produced profound elevations in CM and AP thresholds: 70% of these subjects had their thresholds raised to the limits of the sound system throughout the tested frequency range of 0.10 to 32 kHz. Histopathologic effects associated with CM and AP threshold shifts were primarily limited to the perilabyrinthine compartment, and were greatest in the most basal cochlear turns. Systemic infection with GPCMV produced an immune response, but did not affect CM or AP thresholds. Subsequent inoculation of the inner ear of these seropositive animals with live GPCMV did not result in either CM or AP threshold shifts, or cochlear histopathology. Inoculations of inactivated virus into the inner ears of seronegative and seropositive animals produced only moderate CM and AP threshold effects. Primary GPCMV labyrinthitis thus results in significant cochlear dysfunction and histopathologic changes which are prevented by prior systemic infection with GPCMV.

Stimulation of human synovial fibroblast DNA synthesis by platelet-derived growth factor and fibroblast growth factor. Differences to the activation by IL-1.

The pronounced synovial hyperplasia often found in the joints of patients with rheumatoid arthritis could be explained partially by the action of monocyte-macrophage polypeptides (monokines). This report demonstrates that two cytokines which may be derived from monocyte-macrophage populations, namely platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF), stimulate the DNA synthesis and proliferation of human synovial fibroblast-like cells cultured in low (i.e., 1%) fetal bovine serum. Epidermal growth factor, insulin-like growth factor-I, insulin-like growth factor-II (multiplication stimulating activity) and substance P were inactive. Unlike IL-1, PDGF and FGF do not also stimulate PGE2, plasminogen activator, and hyaluronic acid levels. Thus PDGF and FGF, arising from stimulated monocyte-macrophages, may play a role in the stimulation of mesenchymal cell proliferation that often accompanies chronic inflammatory arthritic disease. The synovial cells respond to a variety of cytokines in different ways suggesting multiple-signaling pathways.

Cytokine interactions promoting DNA synthesis in human synovial fibroblasts.

OBJECTIVE: To evaluate in vitro cytokine combinations that may contribute to the pronounced hyperplasia often found in the joints of patients with rheumatoid arthritis. METHODS: DNA synthesis, in the presence of various combinations of cytokines, was measured in vitro using low serum cultures of passaged synovial fibroblasts derived from nonrheumatoid tissue. RESULTS: Coculture of synovial fibroblasts with platelet derived growth factor (PDGF) and fibroblast growth factor (FGF), at their respective optimal concentrations for DNA synthesis, led to a further increase. In combination with the described synovial fibroblast mitogen, interleukin 1 (IL-1), which can also generate a growth inhibitory cyclooxygenase product, the proliferative responses to PDGF, FGF, transforming growth factor alpha, and epidermal growth factor were enhanced; in some, but not in all of these fibroblast cultures containing IL-1, the achievement of maximal DNA synthesis required that the cyclooxygenase inhibitor, indomethacin, be included. Similar results were obtained when PDGF and FGF were cultured with tumor necrosis factor alpha (TNF alpha), and when IL-1 and TNF alpha were combined. The neuropeptide, substance P (10(-11)-10(-7)M), was inactive by itself and in the presence of IL-1. CONCLUSION: While cytokines individually may be activators of various signalling pathways in the synovial fibroblasts, it is when they are combined that they show their full potential as growth promoters, with possible ramifications for inflammatory joint disease.

Potassium current development and its linkage to membrane expansion during growth of cultured embryonic mouse hippocampal neurons: sensitivity to inhibitors of phosphatidylinositol 3-kinase and other protein kinases.

Hippocampal pyramidal neurons express three major voltage-dependent potassium currents, IA, ID, and IK. During hippocampal development, IA, the rapidly activating and inactivating transient potassium current, is detected soon after pyramidal neurons can be morphologically identified. Appearance of IA in developing pyramidal neurons is dependent on contact with cocultured astroglial cells; cultured pyramidal neurons not in contact with astroglial cells have reduced membrane area and IA (Wu and Barish, 1994). We have examined intracellular signaling pathways that could contribute to the regulation of IA development by probing developing pyramidal neurons with kinase inhibitors. We observed that exposure to LY294002 or wortmannin, inhibitors of phosphatidylinositol (PI) 3-kinase, reduced somatic cross-sectional area, neurite outgrowth, whole-cell capacitance, IA amplitude and density (amplitude normalized to membrane area), and immunoreactivity for Kv4.2 and/or Kv4.3 (potassium channel subunits likely to be present in the channels carrying IA). In contrast, exposure to ML-9 or KN-62, inhibitors of myosin light chain kinase or Ca2+-calmodulin-dependent protein kinase II (CaMKII), reduced membrane area and IA amplitude but did not affect IA density or Kv4. 2/3 immunoreactivity to the same extent as inhibitors of PI 3-kinase. Unexpectedly, exposure to bisindolymaleimide I or calphostin C, inhibitors of protein kinase C (PKC), did not affect membrane area or potassium current development. Our data suggest that PI 3-kinases regulate both A-type potassium channel synthesis and plasmalemmal insertion of vesicles bearing these potassium channels. CaMKII appears to regulate fusion of channel-bearing vesicles with the plasmalemma and myosin light chain kinase to regulate centripetal transport of channel-bearing vesicles from the Golgi. We further suggest that astroglial cells exert their influence on pyramidal neuron development through activation of PI 3-kinases.

Mouse brain potassium channel beta1 subunit mRNA: cloning and distribution during development.

The pore-forming alpha subunits of voltage-gated potassium channels in neurons and other excitable cells are expressed in association with accessory beta subunits. These subunits both promote insertion of channel complexes into surface membranes and influence their electrophysiological properties. As part of an effort to understand the regulation of voltage-gated potassium channels during development, we cloned the mouse homolog of the rat Kvbeta1 potassium channel subunit. Kvbeta1 subunits are known to associate preferentially with Shaker (Kv1)-related alpha subunits. We then used a digoxigenin-tagged cRNA probe and in situ hybridization techniques to visualize the appearance of Kvbeta1 mRNA transcripts during late embryonic and early neonatal development of the mouse brain. We detected Kvbeta1-specific labeling of cells in hippocampus, cerebral cortex, caudate putamen, colliculus, and cerebellum. In hippocampus, we observed Kvbeta1 mRNA in CA3 pyramidal neurons at the earliest time examined, embryonic day 16 (E16). Between E16 and postnatal day 7 (P7), cell labeling increased uniformly across the pyramidal neurons of Ammon's horn (CA1, CA2, and CA3). Subsequently, between P7 and P22, regional differences characteristic of mature hippocampus appeared-intense labeling of neurons in CA3 and CA1, and less in CA2. In cortex, labeling of cells in the subplate and cortical plate layers was observed at E16. During development, the intensity of this labeling increased, and labeled cells persisted into the adult stage in the deep cortical layer (VIb) formed from subplate neurons. Additional labeling of scattered solitary cells in cortical layers II-VIa emerged between P3 and P7 and was prominent in mature cortex. In caudate putamen, Kvbeta1-labeled cells were observed at P1 and were restricted to the lateral and rostral half of the caudate. During development, labeling expanded caudally and medially and eventually filled the mature caudate putamen. In colliculus, a small population of inferior colliculus cells showed labeling at P7, and additional labeling of scattered cells appeared during development. In superior colliculus, labeling was observed only in the adult deep gray layer. In cerebellum, intense labeling was observed in Purkinje cells at all stages between P1 and adult. Labeling was also seen in granule neurons in the external granule layer at early postnatal stages and in the inner granule layer beginning at P7.

Stimulation of human synovial fibroblast DNA synthesis by recombinant human cytokines.

The pronounced synovial hyperplasia often found in rheumatoid joints can be explained at least partially, by the interaction of monocyte-macrophage polypeptides (monokines) and lymphocyte polypeptides (lymphokines) with synovial fibroblast-like cells. We now report that purified recombinant human cytokines, interleukin-1 alpha, interleukin-1 beta, tumor necrosis factor alpha, tumor necrosis factor beta (or lymphotoxin) and, to a variable extent, interferon-gamma, stimulate the DNA synthesis of human synovial fibroblast-like cells cultured in low (i.e., 1%) fetal bovine serum. With the exception of interferon-gamma, the effects of the cytokines were generally elevated by indomethacin, suggesting inhibition of the DNA synthesis by an endogenously produced cyclooxygenase product(s). Consistent with this suggestion, exogenous prostaglandin E2 suppressed cytokine induced DNA synthesis. All of the cytokines studied might play a role in the synovial hyperplasia present in rheumatoid disease.

An anti-inflammatory role for interleukin-11 in established murine collagen-induced arthritis.

Interleukin-11 (IL-11) is a cytokine belonging to the IL-6 family which has both pro- and anti-inflammatory potential. Like IL-6 it can diminish tumour necrosis factor-alpha and IL-1 production, and augment immunoglobulin synthesis. We have explored the immunomodulatory effects of IL-11 treatment in mice in a model of inflammatory autoimmune joint disease, collagen-induced arthritis (CIA). Recombinant human IL-11 was administered at various doses to DBA/1 mice after the onset of CIA. IL-11 treatment caused a significant reduction in the clinical severity of established CIA, which was associated with protection from joint damage, as assessed by histology. Although there was a suggestion at high doses of IL-11 that the anticollagen type II (CII) response may have been augmented, there was no statistically significant effect of IL-11 treatment on anti-CII antibody levels. Similarly, the acute-phase reactant serum amyloid P was only elevated in mice receiving very high doses (50-100 microgram/day) of IL-11. Endogenous IL-11 was abundantly produced in synovial membrane cultures derived from CII-immunized mice with active disease, suggesting that, as in rheumatoid arthritis, this cytokine is spontaneously produced in the inflammatory response in CIA. The results presented here demonstrate an anti-arthritic immunoregulatory role for IL-11 in murine CIA, and suggest that IL-11 is a candidate therapeutic molecule for human inflammatory arthritic diseases.

Validation of the interleukin-10 knockout mouse model of colitis: antitumour necrosis factor-antibodies suppress the progression of colitis.

Advances in understanding pathogenesis and developing new therapies are hastened by the use of effective animal models of disease. In inflammatory bowel disease, such as Crohn's disease, a variety of models have been used, including the IL-10 knockout mouse. However, in order to be truly valuable, the models need to respond to existing therapy in a way which resembles the human disease. In the light of recent developments, in which refractory Crohn's disease responds well to anti-TNF antibody therapy, we set out to validate the IL-10 knockout model of Crohn's disease by examining its response to anti-TNF therapy. We developed a new scoring system for IL-10 knockout mice, similar to the Crohn's Disease Activity Index in humans, analysed stool samples for cytokines and compared the findings with histology. We found that anti-TNF antibody therapy starting at 4 weeks markedly ameliorated the disease, as judged by the clinical score or by histological analysis of the gut. Furthermore, analysis of stool samples for cytokines revealed a marked diminution of inflammatory cytokines, adding a further accurate measure of the improvement. This model may thus be useful for evaluating other therapeutic modalities of relevance to Crohn's disease.

Stimulation of the hyaluronic acid levels of human synovial fibroblasts by recombinant human tumor necrosis factor alpha, tumor necrosis factor beta (lymphotoxin), interleukin-1 alpha, and interleukin-1 beta.

Monocyte/macrophage polypeptides (monokines) alter the properties of synovial cells. This interaction could explain some of the properties of the inflamed synovium in rheumatic disease. Only recently has it been possible to test the action of purified monokines on the target synovial cells. We report here that recombinant human tumor necrosis factor alpha, tumor necrosis factor beta (lymphotoxin), interleukin-1 alpha, and interleukin-1 beta stimulate the hyaluronic acid (HA) levels of human synovial fibroblast-like cells. The effect of monokines was generally inhibited by indomethacin, suggesting the involvement of an endogenous cyclooxygenase product in the stimulation, and by the glucocorticoid, dexamethasone. In contrast, all-trans-retinoic acid stimulated synovial cell plasminogen activator activity but did not increase the HA levels. These findings could help to explain the raised HA levels found in the joint fluids and in the circulation of patients with rheumatic disease.