Effect of complement depletion on lung fluid balance after thrombin

We examined the effect of complement depletion on lung fluid and protein exchange after thrombin-induced pulmonary thromboembolization. Sheep were prepared with lung lymph fistulas to assess pulmonary transvascular fluid and protein dynamics. Studies were made in three groups: in group I (n = 5) pulmonary thromboembolization (PT) was induced by an iv infusion of thrombin (55.0 +/- 12.9 NIH U/kg); in group II (n = 6) cobra venom factor (CVF) was given ip (94.5 +/- 18.8 U/kg/day) for 2 days to deplete complement, and then thrombin (66.4 +/- 37.0 NIH U/kg) was infused to raise pulmonary vascular resistance to the same level as in group I; in group III (n = 10) left atrial pressure (Pla) was increased by 10-15 Torr in normal animals by inflation of a Foley balloon catheter. In group I, thrombin infusion caused an increase in pulmonary lymph flow (Qlym) with a gradual increase in the lymph-to-plasma protein concentration ratio (L/P). In complement-depleted sheep, thrombin caused a transient increase in Qlym, which was associated with a decrease in L/P. In group I an increase in Pla further increased Qlym but without a change in L/P, indicating an increase in lung vascular permeability to proteins; whereas in the decomplemented-thrombin sheep raising Pla increased Qlym but decreased L/P. Results in the latter group were similar to those obtained in normal animals after left atrial hypertension (group III). Therefore the complement system participates in the increase in lung vascular permeability following thrombin-induced microembolization.     

Testicular function of rats following exposure to microwave radiation

Male Sprague-Dawley rats were exposed for 6 h per day for nine days to pulse-modulated microwave radiation (1.3 GHz, at 1-microseconds pulse width, 600 pulses per second). Exposures were carried out in cylindrical waveguide sections at a mean dose rate of 6.3 mW/g; sham controls were treated similarly and received no irradiation. At time periods corresponding to 0.5, 1.0, 2.0, and 4.0 cycles of the seminiferous epithelium, groups of four sham-irradiated and four irradiated rats were killed and the testes removed for analysis. Net mass of the testes, epididymides, and seminal vesicles; daily sperm production (DSP) per testis and per gram of testis; sperm morphology; and the number of epididymal sperm were determined. There were no statistically significant differences between the sham-irradiated and irradiated groups with respect to any measured variable. In a group of seven surrogate animals of similar body mass, the dose rate of 6.3 mW/g caused a net change in body temperature (via rectal probe) of 1.5 degrees C.     

Effects of Rapeseed and Vetch as Green Manure Crops and Fallow on Nematodes and Soil-borne Pathogens

In a rapeseed-squash cropping system, Meloidogyne incognita race 1 and M. javanica did not enter, feed, or reproduce in roots of seven rapeseed cultivars. Both nematode species reproduced at low levels on roots of the third crop of rapeseed. Reproduction of M. incognita and M. javanica was high on squash following rapeseed, hairy vetch, and fallow. The application of fenamiphos suppressed (P = 0.05) root-gall indices on squash following rapeseed, hairy vetch, and fallow; and on Dwarf Essex and Cascade rapeseed, but not Bridger and Humus rapeseed in 1987. The incorporation of 30-61 mt/ha green biomass of rapeseed into the soil 6 months after planting did not affect the population densities of Criconemella ornata, M. incognita, M. javanica, Pythium spp., Rhizoctonia solani AG-4; nor did it consistently increase yield of squash. Hairy vetch supported larger numbers of M. incognita and M. javanica than rapeseed cultivars or fallow. Meloidogyne incognita and M. javanica survived in fallow plots in the absence of a host from October to May each year at a level sufficient to warrant the use of a nematicide to manage nematodes on the following susceptible crop.     

A murine CD4-, CD8- T cell receptor-gamma delta T lymphocyte clone specific for herpes simplex virus glycoprotein I.

The role of TCR-gamma delta T lymphocytes in immune responses is currently not well understood. TCR-gamma delta cells have a limited repertoire suggesting that TCR-gamma delta T a limited number of evolutionarily conserved Ag such as nonpolymorphic MHC and heat shock proteins. TCR-gamma delta T lymphocytes appear in enhanced numbers in skin lesions produced by Mycobacterium leprae and in the synovial fluid of joints affected by rheumatoid arthritis, raising the possibility that this subset of T lymphocytes may play a role in control of infectious processes and in autoimmune diseases. We report the identification of a TCR-gamma delta T cell clone isolated from a HSV-infected mouse that recognizes glycoprotein I of HSV type 1. Clone recognition of glycoprotein I does not appear to require the expression of MHC class I or class II gene products. These data suggest that TCR-gamma delta lymphocytes may play an important role in the immune response to viral infections.     

Integrated Delivery of Antiretroviral Treatment and Pre-exposure Prophylaxis to HIV-1–Serodiscordant Couples: A Prospective Implementation Study in Kenya and Uganda

BackgroundAntiretroviral-based interventions for HIV-1 prevention, including antiretroviral therapy (ART) to reduce the infectiousness of HIV-1 infected persons and pre-exposure prophylaxis (PrEP) to reduce the susceptibility of HIV-1 uninfected persons, showed high efficacy for HIV-1 protection in randomized clinical trials. We conducted a prospective implementation study to understand the feasibility and effectiveness of these interventions in delivery settings.ConclusionsIntegrated delivery of time-limited PrEP until sustained ART use in African HIV-1-serodiscordant couples was feasible, demonstrated high uptake and adherence, and resulted in near elimination of HIV-1 transmission, with an observed HIV incidence of <0.5% per year compared to an expected incidence of >5% per year.     

Inspiratory flow rate and dead space in dogs

It is generally accepted that a stationary concentration front is established in the tracheobronchial tree during the inspiratory phase of single- and multiple-breath washouts. The anatomic position of this front, which is determined by the balance between diffusive flux toward the airway opening and convective flux toward the periphery, is frequently used to predict the effects of molecular diffusivity and inspiratory flow rate on dead space. Although there is substantial experimental evidence supporting the predictive effect of molecular diffusivity, there is little evidence regarding the effect of convective flow. This study confirmed the predictions for the effects of molecular diffusivity but contradicted those for the effects of inspiratory flow. We measured dead space by multiple- and single-breath inert gas washout techniques and also measured physiological dead space in dogs for inspiratory flow rates of 10-71 ml.kg-1.s-1. None of the three measures of dead space increased over the entire range of flow rate, as predicted by contemporary gas transport models. A possible explanation for these findings is that axial dispersion coefficients in the anatomic region where stationary fronts are believed to develop (respiratory bronchioles and alveolar ducts) significantly increase with convective flow rate rather than remain equal to molecular diffusivity.     

Regulation of expression of a wound-inducible tomato inhibitor I gene in transgenic nightshade plants

A wound-inducible proteinase Inhibitor I gene from tomato containing 725 bp of the 5 region and 2.5 kbp of the 3 region was stably incorporated into the genome of black nightshade plants (Solanum nigrum) using an Agrobacterium Ti plasmid-derived vector. Transgenic nightshade plants were selected that expressed the tomato Inhibitor I protein in leaf tissue. The leaves of the plants contained constitutive levels of the inhibitor protein of up to 60 g/g tissue. These levels increased by a factor of about two in response to severe wounding. Only leaves and petioles exhibited the presence of the inhibitor, indicating that the gene exhibited the same tissue specificity of expression found in situ in wounded tomato leaves. Inhibitor I was extracted from leaves of wounded transformed nightshade plants and was partially purified by affinity chromatography on a chymotrypsin-Sepharose column. The affinity-purified protein was identical to the native tomato Inhibitor I in its immunological reactivity and in its inhibitory activity against chymotrypsin. The protein exhibited the same M _r of 8 kDa as the native tomato Inhibitor I and its N-terminal amino acid sequence was identical to that of the native tomato inhibitor I, indicating that the protein was properly processed in nightshade plants. These expriments are the first report of the expression of a member of the wound-inducible tomato Inhibitor I gene family in transgenic plants. The results demonstrate that the gene contains elements that can be regulated in a wound-inducible, tissuespecific manner in nightshade plants.     

Irreversible inactivation of adenylyl cyclase by the "P"-site agonist 2',5'-dideoxy-,3'-p-fluorosulfonylbenzoyl adenosine

2',5'-Dideoxy,3'-p-fluorosulfonylbenzoyl Adenosine (2',5'-dd3'-FSBA) was synthesized and found to be an agonist and affinity label for the "P"-site of adenylyl cyclase. This compound irreversibly inactivated both a crude detergent-dispersed adenylyl cyclase from rat brain and the partially purified enzyme from bovine brain. The irreversible inactivation by 100 to 200 microM 2',5'-dd3'-FSBA was blocked in a concentration-dependent manner by several established P-site inhibitors of adenylyl cyclase, 2',5'-dideoxyadenosine, 2'-d3'-AMP, adenosine, and 2'-deoxyadenosine, but not by inosine, N6-(phenylisopropyl)adenosine, adenine, 2'-d3':5'-cAMP, or 5'-AMP, agents known not to act at the P-site. Moreover, irreversible inactivation by 2',5'-dd3'-FSBA occurred in the presence of ATP at concentrations up to 3 mM, making it unlikely that inactivation was due to an effect on the enzyme's catalytic site. Adenylyl cyclase was also irreversibly inactivated by 5'-FSBA, although modestly (less than 20%) and apparently nonspecifically. Dithiothreitol protected the enzyme from irreversible inactivation by 2',5'-dd3'-FSBA, but reversible inhibition of the enzyme was still observed, although with reduced potency. When 2 mM dithiothreitol was added after a 30-min preincubation with 2',5'-dd3'-FSBA, the rat brain enzyme was partially (approximately 80%) reactivated. The data suggest that 2',5'-dd3'-FSBA may irreversibly inactivate adenylyl cyclase by reacting with a cysteinyl moiety in proximity to the P-site domain of the enzyme. These data together with results of studies of P-site inhibition kinetics published elsewhere (Johnson, R. A., and Shoshani, I. (1990) J. Biol. Chem. 265, 11595-11600) strongly suggest that the P-site and catalytic site are distinct domains on the enzyme. 2',5'-dd3'-FSBA, and especially its radiolabeled analog, should prove to be a useful probe for structural studies of adenylyl cyclase, particularly with regard to the P-site.     

The magnetic and electronic properties of Methanobacterium thermoautotrophicum (strain delta H) methyl coenzyme M reductase and its nickel tetrapyrrole cofactor F430. A low temperature magnetic circular dichroism study

Variable temperature magnetic circular dichroism (MCD) spectroscopy has been used to characterize the magnetic and electronic properties of the Ni(II) tetrapyrrole, F430, which is the cofactor of the S-methyl coenzyme M methylreductase enzyme from Methanobacterium thermoautotrophicum (strain delta H). 4-Coordinate forms are found to be diamagnetic (S = 0 ground state), whereas 6-coordinate forms are paramagnetic (S = 1 ground state). MCD studies, together with parallel low temperature UV-visible absorption and resonance Raman investigations, show that the equilibrium distribution of 4-coordinate square-planar and 6-coordinate bis-aquo forms of the native isomer of F430 in aqueous solution is affected by both temperature and the presence of glycerol. In the presence of 50% glycerol, the 12,13-diepimer of F430 is shown to be partially 6-coordinate in frozen solution at low temperature. Low temperature MCD magnetization data allow the determination of the axial zero-field splitting (D) of the S = 1 ground state of bis-ligand complexes of F430. The value of D is sensitive to the nature of the Ni(II) axial ligands: bis-aquo F430, D = +9 +/- 1 cm-1; bis-imidazole F430, D = -8 +/- 2 cm-1. Measurement of D = +10 +/- 1 cm-1 for F430 in the methylreductase holoenzyme argues strongly against histidine imidazole coordination to Ni(II) in the enzyme. The possible existence of alcoholic or phenolic oxygen-containing ligands (serine, threonine, tyrosine, water) to Ni(II) in the enzyme-bound cofactor is discussed.